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ORGANIC SPECTROSCOPY

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DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with AFRICURE PHARMA, ROW2TECH, NIPER-G, Department of Pharmaceuticals, Ministry of Chemicals and Fertilizers, Govt. of India as ADVISOR, earlier assignment was with GLENMARK LIFE SCIENCES LTD, as CONSUlTANT, Retired from GLENMARK in Jan2022 Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 32 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri, etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him Open superstar worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 32 PLUS year tenure till date Feb 2023, Around 35 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 100 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 100 Lakh plus views on dozen plus blogs, 227 countries, 7 continents, He makes himself available to all, contact him on +91 9323115463, email amcrasto@gmail.com, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 38 lakh plus views on New Drug Approvals Blog in 227 countries......https://newdrugapprovals.wordpress.com/ , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc He has total of 32 International and Indian awards

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Secutrelvir


Secutrelvir

CAS 2996148-73-1

MF C23H16Cl2F3N5O2 MW522.3 g/mol

2-[5-(3-chloro-4-fluorophenyl)-3-(5-chloro-3-pyridinyl)-6-(6,6-difluoro-2-azaspiro[3.3]heptan-2-yl)-2,4-dioxopyrimidin-1-yl]acetonitrile

2-(5-(3-chloro-4-fluorophenyl)-3-(5-chloropyridin-3-yl)-6-(6,6-difluoro-2-azaspiro[3.3]heptan-2-yl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)acetonitrile

[5-(3-chloro-4-fluorophenyl)-3-(5-chloropyridin-3-yl)-6-(6,6-difluoro-2-azaspiro[3.3]heptan-2-yl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl]acetonitrile

[5-(3-chloro-4-fluorophenyl)-3-(5-chloropyridin-3-yl)-6-(6,6-difluoro-2-azaspiro[3.3]heptan-2-yl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl]acetonitrile
protease inhibitor, antiviral, S-892216, S 892216, FMV68MJ8XK

Secutrelvir (also known by its developmental code S-892216) is an advanced, next-generation oral antiviral drug developed by the pharmaceutical company Shionogi. It functions as a potent SARS-CoV-2 3C-like protease (3CLpro / \(M^{\text{pro}}\)) inhibitor designed primarily for the treatment of COVID-19.

As of August 2026, the drug has entered late-stage development, with Shionogi moving into Phase 3 clinical trials to assess its efficacy and safety in patients.

Key Properties & Advantages

Unlike first-generation COVID-19 antivirals, secutrelvir was structurally optimized to address the limitations of existing treatments like Paxlovid (nirmatrelvir/ritonavir) and Shionogi’s own Xocova (ensitrelvir).

  • No CYP Booster Required: Secutrelvir offers 100% oral bioavailability without needing a pharmacokinetic booster like ritonavir. This dramatically reduces the risk of severe drug-drug interactions that complicate Paxlovid prescriptions.
  • Overcoming Viral Resistance: In laboratory assays, the compound demonstrates zero cross-resistance to viral mutants that have grown resistant to nirmatrelvir or ensitrelvir (such as those carrying E166V or M49L mutations).
  • High Off-Target Selectivity: It features high selectivity (>15,000-fold) over human proteases, ensuring it specifically targets viral replication without disrupting normal human cellular functions.
  • Broad Spectrum (Pan- β-CoV): The compound maintains high potency against a wide range of SARS-CoV-2 variants—including newer strains like Omicron JN.1—as well as other coronaviruses like SARS-CoV and MERS-CoV.

Mechanism of Action

Secutrelvir relies on a structure-based design incorporating a nitrile warhead. It enters the catalytic active site of the virus’s main protease (\(M^{\text{pro}}\)) and forms a reversible covalent bond with the catalytic amino acid residue cysteine C145. By binding to this pocket, it halts the protease from cutting viral polyproteins, effectively stopping viral replication in its tracks.

[Secutrelvir (Nitrile Warhead)]
▼ (Reversible Covalent Binding)
[Cysteine C145 of 3CLpro] ──► Blocked Protease Activity ──► Viral Replication Stopped

Clinical Evaluation Status

  • Pharmacokinetics: Clinical pharmacology data released by Shionogi Medical demonstrated excellent safety, high tolerability, and no clinically relevant food effects, meaning the drug can be taken with or without food.
  • Phase 3 Trials (NCT07743580 / NCT07746544): Late-stage double-blind, placebo-controlled interventional studies are assessing the drug in symptomatic, non-hospitalized COVID-19 patients who are at risk of progressing to severe illness. To qualify for the trials, patients must receive the drug within 72 hours of symptom onset
  • A Study of Secutrelvir in Participants With Coronavirus Disease 2019 (COVID-19) Who Are at High Risk for Progression to Severe DiseaseCTID:NCT07743580Phase:Phase 3Status:RecruitingDate:2026-08-25
  • Study of Secutrelvir in Participants With COVID-19CTID:NCT07746544Phase:Phase 3Status:Not yet recruitingDate:2026-08-05
  • A Study of S-892216 in Participants With COVID-19CTID:NCT06928051Phase:Phase 2Status:CompletedDate:2025-09-30
  • A Drug-drug Interaction Study of S-892216 Coadministered With Carbamazepime to Healthy Adult ParticipantsCTID:NCT06751017Phase:Phase 1Status:CompletedDate:2025-03-11

Syn

US20250092056,

https://patentscope.wipo.int/search/en/detail.jsf?docId=US451712998&_cid=P20-MTTHQ4-21870-1

Example 6

Synthesis of Compound (I-077)

Step 1 Synthesis of Compound (I-077)

      Compound (I-055) (25.0 mg, 0.059 mmol), 6,6-difluoro-2-azaspiro[3.3]heptane trifluoroacetic acid salt (17.4 mg, 0.070 mmol), N, N-diisopropylethylamine (20.5 μL, 0.117 mmol), and DMF (0.5 mL) were mixed, and the solution was stirred at 60° C. for 2 hours. Water (2 mL) was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with water, dried over sodium sulfate, and filtered. The filtrate was concentrated, and ethyl acetate (0.05 mL), hexane (0.125 mL), and diisopropyl ether (0.125 mL) were added. The obtained precipitate was collected by filtration and washed with diisopropyl ether. The obtained solid was dried under reduced pressure to obtain Compound (I-077) (22.0 mg, 0.042 mmol, yield 72%).
       1H-NMR (CDCl 3) δ: 2.75 (4H, t, J=12.0 Hz), 4.02 (4H, s), 4.74 (2H, s), 7.16-7.18 (2H, m), 7.32-7.35 (1H, m), 7.65 (1H, t, J=2.1 Hz), 8.43 (1H, d, J=2.3 Hz), 8.61 (1H, d, J=2.3 Hz).
      LC/MS (ESI): m/z=522, RT=2.27 min, LC/MS measurement condition A

PAT

[WO2023195530A1]

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References

Uracil derivatives having virus replication inhibitory activity and pharmaceutical composition comprising the samePublication Number:

US-2025092056-A1Priority Date:2022-04-08

////secutrelvir, anax labs, protease inhibitor, antiviral, S-892216, S 892216, FMV68MJ8XK

#secutrelvir, #anax labs, #protease inhibitor, #antiviral, #S-892216, #S 892216, #FMV68MJ8XK

Ratutrelvir


Ratutrelvir

CAS 2929236-94-0

MF C27H32F3N5O4 MW547.6 g/mol

(1R,2S,5S)-N-[(1S)-1-cyano-2-(2-oxo-1,3-dihydroindol-3-yl)ethyl]-3-[(2S)-3,3-dimethyl-2-[(2,2,2-trifluoroacetyl)amino]butanoyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2-carboxamide

3-Azabicyclo[3.1.0]hexane-2-carboxamide, N-[(1S)-1-cyano-2-(2,3-dihydro-2-oxo-1H-indol-3-yl)ethyl]-3-[(2S)-3,3-dimethyl-1-oxo-2-[(2,2,2-trifluoroacetyl)amino]butyl]-6,6-dimethyl-, (1R,2S,5S)-

(1R,2S,5S)-N-{(1S)-1-cyano-2-[(3RS)-2-oxo-2,3-dihydro-1H-indol-3-yl]ethyl}-3-[(2S)-3,3-dimethyl-2-(2,2,2-trifluoroacetamido)butanoyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2-carboxamide
protease inhibitor, antiviral, TRX01, 83-0060, TRX 01, VR2S5588W2,

Ratutrelvir is an investigational new drug that is being evaluated by Traws Pharma[1] for the treatment of COVID-19 infections.[2][3] It is a 3C-like protease inhibitor.[3][4]

Clinical trials

Ratutrelvir is currently in a phase 2 clinical trial to test the effectiveness and safety of the drug in patients with COVID-19[5] and a preliminary analysis of the results has been released.[6]

Ratutrelvir (also known as TRX01 or 83-0060) is an investigational, oral antiviral medication being developed by Traws Pharma for the treatment of mild-to-moderate COVID-19.

Key Characteristics

  • Mechanism: It functions as a covalent inhibitor of the SARS-CoV-2 main protease (\(M^{pro}\) / 3CL protease), preventing the virus from replicating.
  • Ritonavir-Free: Unlike Paxlovid, ratutrelvir does not require a metabolic booster like ritonavir. This prevents severe drug-drug interactions and broadens its usability.
  • Dosing: It is designed as a once-daily oral regimen taken over 10 days.

Clinical Development & Trial Results

According to Phase 2 data released by Traws Pharma in early 2026:

  • Efficacy: Shows a comparable or faster time to sustained symptom resolution compared to Paxlovid.
  • No Viral Rebound: Patients treated with ratutrelvir experienced no viral rebound events.
  • Paxlovid-Ineligible Benefit: The drug successfully treated patients who could not take Paxlovid due to medical contraindications.
  • Fewer Side Effects: It reported fewer treatment-related adverse events (10% vs 23.3% for Paxlovid) and avoids taste disturbances (dysgeusia).

PAT

[WO2023093834A1]

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2023093834&_cid=P11-MSWMDL-65476-1

Example 1: Preparation of (1R,2S,5S)-N-((2S)-1-amino-1-carbonyl-3-(2-carbonyldihydroindole-3-yl)propane-2-yl)-3-((S)-3,3-dimethyl-2-(2,2,2-trifluoroacetamido)butyryl)-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2-carboxamide (compound 1) 

[0138]The synthesis route is as follows:

The structural characterization data of compound 1-P2 are as follows: 

[0153]m/z(ESI):548[M+H] 。 

[0154]

1H NMR:(400MHz,DMSO-d6)δ10.58-10.41(m,1H),9.42-9.00(m,2H),7.39-7.26(m,1H),7.21-7.13(m,1H),7.03-6.78(m,2H),5.30-5.16(m,1H),4.44-4.30(m,1H),4.22(s,1H),4.00-3.86(m,1H),3.75-3.64(m,1H),3.58-3.47(m,1H),2.19-2.05(m,1H),1.63-1.54(m,1H),1.35(d,J=7.7Hz,1H),1.04(s,3H),1.01-0.96(m,2H),0.94(s,2H),0.90-0.79(m,9H)。

PAT

https://patentscope.wipo.int/search/en/detail.jsf;jsessionid=4879FE25FD0F775B266E953E785747E1.wapp1nB?docId=WO2026122604&_cid=P11-MSWM6K-58737-1

Synthesis of compound (I)

31.

ASB

Synthesis of compound (I)

31.

ASB

PAT

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References

References

  1.  WO 2023245162, Rogovoy B, Kysil V, Berishvili V, Pauza CD, Zapata JC, Moreno SM, Li H, Orry A, Lam PC, Abagyan R, Savchuk N, “Compounds for treatment a coronavirus infection”, published 2023-12-21, assigned to Trawsfynydd Therapeutics Inc.
  2.  “International Nonproprietary Names for Pharmaceutical Substances (INN) Recommended INN: List 94” (PDF). WHO Drug Information39 (3). World Health Organization: 809–1060 (976). 2025.
  3.  “Travatrelvir – Traws Pharma”AdisInsight. Springer Nature Switzerland AG. Retrieved 5 July 2026.
  4.  “Ratutrelvir | Ligand page”IUPHAR/BPS Guide to PHARMACOLOGY.
  5.  “Early-stage Trial to Determine a Safe and Effective Dose for Ratutrelvir in Patients With Mild to Moderate COVID-19”ClinicalTrials.gov. U.S. National Library of Medicine. 17 January 2026. Clinical trial record for NCT07157007. Retrieved 5 July 2026.
  6.  Contagion Editorial Team (8 July 2026). “Traws Pharma Reports Differentiated COVID-19 and Influenza Antiviral Progress”Contagion Live.
Clinical data
Other names83-0060, TRX01
Identifiers
IUPAC name
CAS Number2929236-94-0
PubChem CID169861725
IUPHAR/BPS13737
UNIIVR2S5588W2
Chemical and physical data
FormulaC27H32F3N5O4
Molar mass547.579 g·mol−1
3D model (JSmol)Interactive image
SMILES
InChI

///////////ratutrelvir, anax labs, protease inhibitor, antiviral, TRX01, 83-0060, TRX 01, VR2S5588W2,

#ratutrelvir, #anax labs, #protease inhibitor, #antiviral, #TRX01, #83-0060, #TRX 01, #VR2S5588W2,

Netanasvir


Netanasvir

CAS 2007900-70-9

MF C51H58N8O7 MW895.1 g/mol

methyl N-[(1R)-2-[(2S,4S)-2-[5-[7-[2-[(2S,5S)-1-[(2S)-2-(methoxycarbonylamino)-3-methylbutanoyl]-5-methylpyrrolidin-2-yl]-3H-benzo[e]benzimidazol-7-yl]-2,3-dihydro-1H-inden-4-yl]-1H-imidazol-2-yl]-4-(methoxymethyl)pyrrolidin-1-yl]-2-oxo-1-phenylethyl]carbamate

antiviral, Dongweizhuo, HCV, Antaitavir Hasophate, HEC 74647 PA, 4Y7YD32BYY

Netanasvir (commonly prescribed as netanasvir phosphate) is a direct-acting antiviral medication primarily used to treat chronic hepatitis C virus (HCV) infection. It was approved by the China National Medical Products Administration (NMPA) under the trade name Dongweizhuo.

Key Clinical Information

  • Mechanism of Action: It acts as a potent and selective NS5A inhibitor. By targeting the HCV NS5A protein, it successfully blocks viral RNA replication, virion assembly, and viral clearance mechanisms.
  • Combination Therapy: It is exclusively indicated for use in combination with encofosbuvir (an NS5B polymerase inhibitor).
  • Target Genotypes: The combination regimen effectively treats adult patients with chronic HCV genotypes 1, 2, 3, or 6.
  • Patient Profiles: It is suitable for patients who are either treatment-naïve or have been previously treated with interferon, with or without compensated liver cirrhosis.
  • Administration & Elimination: Taken orally, the drug demonstrates high metabolic stability, with feces serving as its primary elimination pathway
  • OriginatorSunshine Lake Pharma
  • ClassAntivirals
  • Mechanism of ActionHepatitis C virus NS 5 protein inhibitors
  • RegisteredHepatitis C
  • 08 Feb 2025Registered for Hepatitis C (Combination therapy, Treatment-experienced) in China (PO)
  • 08 Feb 2025Registered for Hepatitis C (Combination therapy, Treatment-naive) in China (PO)
  • 31 Dec 2023NMPA, China accepts NDA for netanasvir for Hepatitis C for review

Netanasvir is an antiviral drug used to treat hepatitis C virus (HCV).[1] In China, netansavir is approved for use in combination with encofosbuvir for the treatment of adult patients with chronic HCV genotypes 1, 2, 3, or 6, who are either treatment-naive or have been previously treated with interferon.[2]

PAT

Compounds as hepatitis c virus inhibitors and pharmaceutical uses thereof

Publication Number: WO-2016141890-A1

Priority Date: 2015-03-12

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2016141890&_cid=P22-MRH62L-18160-1

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References

  1.  “Netanasvir phosphate – Sunshine Lake Pharma”Adis Insight. Springer Nature Switzerland AG.
  2.  “Netanasvir Phosphate Capsules Approved for Marketing by China NMPA”National Medical Products Administration. 2025-06-11.
Clinical data
Trade names东卫卓; Dongweizhuo
Legal status
Legal statusRx in China
Identifiers
IUPAC name
CAS Number2007900-70-9
PubChem CID122535557
UNII4Y7YD32BYY
Chemical and physical data
FormulaC51H58N8O7
Molar mass895.074 g·mol−1
3D model (JSmol)Interactive image
SMILES
InChI

//////////netanasvir, anax labs,  APPROVALS 2025, CHINA 2025, antiviral, Dongweizhuo, HCV, Antaitavir Hasophate, HEC 74647 PA, 4Y7YD32BYY

#netanasvir, #anax labs,  #APPROVALS 2025, #CHINA 2025, #antiviral, #Dongweizhuo, #HCV, #Antaitavir Hasophate, #HEC 74647 PA, #4Y7YD32BYY

Bulevirtide-gmod


Bulevirtide-gmod

CAS 2012558-47-1.

MF C248H355N65O72 MW 5399 g/mol

FDA 2026, APPROVALS 2026, 5/22/2026, Hepcludex, WKM56H3TLB

To treat chronic hepatitis delta virus infection in adults without cirrhosis or with compensated cirrhosis


N-myristoyl-glycyl-L-threonyl-L-asparagyl-L-leucyl-L-seryl-L-valyl-L-prolyl-L-asparagyl-L-prolyl-L-leucyl-glycyl-L-phenylalanyl-L-phenylalanyl-L-prolyl-L-alpha-aspartyl-L-histidyl-L-glutaminyl-L-leucyl-L-alpha-aspartyl-L-prolyl-L-alanyl-L-phenylalanyl-glycyl-L-alanyl-L-asparagyl-L-seryl-L-asparagyl-L-asparagyl-L-prolyl-L-alpha-aspartyl-L-tryptophyl-L-alpha-aspartyl-L-phenylalanyl-L-asparagyl-L-prolyl-L-asparagyl-L-lysyl-L-alpha-aspartyl-L-histidyl-L-tryptophyl-L-prolyl-L-alpha-glutamyl-L-alanyl-L-asparagyl-L-lysyl-L-valyl-glycinamide

(4S)-4-[[(2S)-1-[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-4-amino-2-[[(2S)-1-[(2S)-4-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-1-[(2S)-4-amino-2-[[(2S)-4-amino-2-[[(2S)-2-[[(2S)-4-amino-2-[[(2S)-2-[[2-[[(2S)-2-[[(2S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-[[2-[[(2S)-2-[[(2S)-1-[(2S)-4-amino-2-[[(2S)-1-[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-4-amino-2-[[(2S,3R)-3-hydroxy-2-[[2-(tetradecanoylamino)acetyl]amino]butanoyl]amino]-4-oxobutanoyl]amino]-4-methylpentanoyl]amino]-3-hydroxypropanoyl]amino]-3-methylbutanoyl]pyrrolidine-2-carbonyl]amino]-4-oxobutanoyl]pyrrolidine-2-carbonyl]amino]-4-methylpentanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-3-phenylpropanoyl]pyrrolidine-2-carbonyl]amino]-3-carboxypropanoyl]amino]-3-(1H-imidazol-4-yl)propanoyl]amino]-5-oxopentanoyl]amino]-4-methylpentanoyl]amino]-3-carboxypropanoyl]pyrrolidine-2-carbonyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]acetyl]amino]propanoyl]amino]-4-oxobutanoyl]amino]-3-hydroxypropanoyl]amino]-4-oxobutanoyl]amino]-4-oxobutanoyl]pyrrolidine-2-carbonyl]amino]-3-carboxypropanoyl]amino]-3-(1H-indol-3-yl)propanoyl]amino]-3-carboxypropanoyl]amino]-3-phenylpropanoyl]amino]-4-oxobutanoyl]pyrrolidine-2-carbonyl]amino]-4-oxobutanoyl]amino]hexanoyl]amino]-3-carboxypropanoyl]amino]-3-(1H-imidazol-4-yl)propanoyl]amino]-3-(1H-indol-3-yl)propanoyl]pyrrolidine-2-carbonyl]amino]-5-[[(2S)-1-[[(2S)-4-amino-1-[[(2S)-6-amino-1-[[(2S)-1-[(2-amino-2-oxoethyl)amino]-3-methyl-1-oxobutan-2-yl]amino]-1-oxohexan-2-yl]amino]-1,4-dioxobutan-2-yl]amino]-1-oxopropan-2-yl]amino]-5-oxopentanoic acid

Bulevirtide-gmod, sold under the brand name Hepcludex, is the first and only FDA-approved medication for treating chronic hepatitis delta virus (HDV) infection in adults. Developed by Gilead Sciences, it received accelerated approval from the U.S. Food and Drug Administration (FDA) on May 22, 2026, filling a critical gap for patients with this severe viral liver disease.

Indication and Clinical Use

  • Target Patient Profile: Approved for adults with chronic HDV who have compensated cirrhosis or no cirrhosis.
  • The Clinical Need: HDV only occurs as a co-infection in individuals who already have Hepatitis B (HBV). It is considered the most aggressive form of viral hepatitis, often accelerating liver scarring (fibrosis), liver failure, and liver cancer.
  • Basis of Approval: The FDA granted accelerated approval based on Phase 3 MYR301 study data, which demonstrated a significant reduction in viral HDV RNA and the normalization of alanine aminotransferase (ALT) liver enzymes.

Mechanism of Action

Bulevirtide-gmod is a first-in-class entry inhibitor. It works by binding to and blocking the sodium taurocholate co-transporting polypeptide (NTCP) receptor on liver cells. Because HDV and HBV rely on this specific receptor to enter hepatocytes, the drug successfully disrupts the viral life cycle and prevents the virus from spreading to healthy liver cells.

Dosage and Administration

  • Form: Supplied as a lyophilized powder for injection.
  • Dose: The recommended dose is 8.5 mg once daily.
  • Administration: Delivered via subcutaneous injection (under the skin).

Safety and Side Effects

  • Boxed Warning: The drug carries a prominent warning regarding the risk of severe acute exacerbations of hepatitis D and B if treatment is discontinued. Stopping the medication can cause severe, life-threatening viral flares, requiring close medical monitoring for at least 6 months post-treatment.
  • Common Side Effects: The most frequent adverse reactions of patients) include:
    • Injection site reactions
    • Headache
    • Abdominal pain
    • Fatigue
    • Pruritus (itching)

Bulevirtide, sold under the brand name Hepcludex, is an antiviral medication used for the treatment of chronic hepatitis D (in the presence of hepatitis B).[8]

The most common side effects include raised levels of bile salts in the blood and reactions at the site of injection.[8]

Bulevirtide works by attaching to and blocking a receptor (target) through which the hepatitis delta and hepatitis B viruses enter liver cells.[8] By blocking the entry of the virus into the cells, it limits the ability of HDV to replicate and its effects in the body, reducing symptoms of the disease.[8]

Bulevirtide was approved for medical use in the European Union in July 2020,[8] and in Canada in August 2025.[5]

Medical uses

Bulevirtide is indicated for the treatment of chronic hepatitis delta virus (HDV) infection in plasma (or serum) HDV-RNA positive adult patients with compensated liver disease.[8][10]

Pharmacology

Mechanism of action

Bulevirtide binds and inactivates the sodium/bile acid cotransporter, blocking both hepatitis B and hepatitis D viruses from entering hepatocytes.[11]

The hepatitis B virus uses its surface lipopeptide pre-S1 for docking to mature liver cells via their sodium/bile acid cotransporter (NTCP) and subsequently entering the cells. Myrcludex B is a synthetic N-acylated pre-S1[12][13] that can also dock to NTCP, blocking the virus’s entry mechanism.[14]

Bulevirtide is also effective against hepatitis D because the hepatitis D virus uses the same entry receptor as the hepatitis B virus and is only effective in the presence of a hepatitis B virus infection.[14]

Pre-clinical data in mice suggests that pharmacological inhibition of NTCP-mediated bile salt uptake may also be effective to lower hepatic bile salt accumulation in cholestatic conditions. This reduces hepatocellular damage.[15] An increased ratio of phospholipid to bile salts seen in bile upon NTCP inhibition may further contribute to the protective effect as bile salts are less toxic in presence of phospholipids.[16]

Structural formula

Bulevirtide is a 47-amino acid peptide with the following sequence:[17]

CH3(CH2)12COGlyThrAsnLeuSerValPro-Asn-Pro-Leu-Gly-Phe-Phe-Pro-AspHisGln-Leu-Asp-Pro-Ala-Phe-Gly-Ala-Asn-Ser-Asn-Asn-Pro-Asp-Trp-Asp-Phe-Asn-Pro-Asn-Lys-Asp-His-Trp-Pro-Glu-Ala-Asn-Lys-Val-Gly-NH2 (C13H27CO-GTNLSVPNPLGFFPDHQLDPAFGANSNNPDWDFNPNKDHWPEANKVG-NH2)

SYN

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2024073572&_cid=P11-MPNG4J-82875-1

PATENTS

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References

References

  1.  Deterding K, Wedemeyer H (2019). “Beyond Pegylated Interferon-Alpha: New Treatments for Hepatitis Delta”. AIDS Reviews21 (3): 126–134. doi:10.24875/AIDSRev.19000080PMID 31532397S2CID 202674681.
  2.  “Hepcludex (bulevirtide acetate)”Therapeutic Goods Administration (TGA). 12 August 2024. Retrieved 12 October 2024.
  3.  “Therapeutic Goods (Poisons Standard—June 2024) Instrument 2024”Federal Register of Legislation. 30 May 2024. Retrieved 10 June 2024.
  4.  “Hepcludex (Gilead Sciences Pty Ltd)”Therapeutic Goods Administration (TGA). 13 September 2024. Retrieved 15 September 2024.
  5.  “Hepcludex Product information”Health Canada. 8 August 2025. Retrieved 20 August 2025.
  6.  “Summary Basis of Decision for Hepcludex”Drug and Health Products Portal. 29 September 2025. Retrieved 12 October 2025.
  7.  “Hepcludex 2 mg powder for solution for injection – Summary of Product Characteristics (SmPC)”(emc). 30 March 2022. Retrieved 1 July 2022.
  8.  “Hepcludex EPAR”European Medicines Agency (EMA). 26 May 2020. Retrieved 12 August 2020. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged.
  9.  “Hepcludex Product information”Union Register of medicinal products. Retrieved 3 March 2023.
  10.  “Summary of opinion: Hepcludex” (PDF). European Medicines Agency (EMA). 28 May 2020.
  11.  Francisco EM (29 May 2020). “Hepcludex”European Medicines Agency (EMA)Archived from the original on 15 June 2020. Retrieved 6 August 2020.
  12.  Volz T, Allweiss L, Ben MBarek M, Warlich M, Lohse AW, Pollok JM, et al. (May 2013). “The entry inhibitor Myrcludex-B efficiently blocks intrahepatic virus spreading in humanized mice previously infected with hepatitis B virus”. Journal of Hepatology58 (5): 861–867. doi:10.1016/j.jhep.2012.12.008PMID 23246506.
  13.  Abbas Z, Abbas M (August 2015). “Management of hepatitis delta: Need for novel therapeutic options”World Journal of Gastroenterology21 (32): 9461–9465. doi:10.3748/wjg.v21.i32.9461PMC 4548107PMID 26327754.
  14.  Spreitzer H (14 September 2015). “Neue Wirkstoffe – Myrcludex B”. Österreichische Apothekerzeitung (in German) (19/2015): 12.
  15.  Na+ -taurocholate cotransporting polypeptide inhibition has hepatoprotective effects in cholestasis in mice. Slijepcevic D, Roscam Abbing RLP, Fuchs CD, Haazen LCM, Beuers U, Trauner M, Oude Elferink RPJ, van de Graaf SFJ. Hepatology. 2018 Sep;68(3):1057-1069. doi: 10.1002/hep.29888
  16.  Roscam Abbing RL, Slijepcevic D, Donkers JM, Havinga R, Duijst S, Paulusma CC, et al. (January 2020). “Blocking Sodium-Taurocholate Cotransporting Polypeptide Stimulates Biliary Cholesterol and Phospholipid Secretion in Mice”Hepatology71 (1): 247–258. doi:10.1002/hep.30792PMC 7003915PMID 31136002.
  17.  Sauter M, Blank A, Stoll F, Lutz N, Haefeli WE, Burhenne J (September 2021). “Intact plasma quantification of the large therapeutic lipopeptide bulevirtide”Analytical and Bioanalytical Chemistry413 (22): 5645–5654. doi:10.1007/s00216-021-03384-7PMC 8410713PMID 34018034.
Clinical data
Pronunciation/bjuːˈlɛvɪrtaɪd/
byoo-LEH-vir-tyde
Trade namesHepcludex
Other namesMyrB, Myrcludex-B[1]
License dataUS DailyMedBulevirtide
Pregnancy
category
AU: B1[2]
Routes of
administration
Subcutaneous
ATC codeJ05AX28 (WHO)
Legal status
Legal statusAU: S4 (Prescription only)[3][4][2]CA℞-only[5][6]UK: POM (Prescription only)[7]EU: Rx-only[8][9]
Identifiers
CAS Number2012558-47-1
DrugBankDB15248
ChemSpider129157549
UNIIWKM56H3TLB
KEGGD11877as salt: D11878
ChEMBLChEMBL4297711
Chemical and physical data
FormulaC248H355N65O72
Molar mass5398.951 g·mol−1
3D model (JSmol)Interactive image
SMILES
InChI

/////////Bulevirtide-gmod, ANAX LABS, FDA 2026, APPROVALS 2026, Hepcludex, WKM56H3TLB, ANTIVIRALS

#Bulevirtide-gmod, #ANAX LABS, #FDA 2026, #APPROVALS 2026, #Hepcludex, #WKM56H3TLB, #ANTIVIRALS

Encofosbuvir


Encofosbuvir, Yiqibuvir

CAS 2232134-77-7

MF C30H42FN4O13PS MW 748.7 g/mol

  • L-Alanine, O3-[N-(methoxycarbonyl)-L-methionyl]-[P(S),2’R]-2′-deoxy-2′-fluoro-3-(hydroxymethyl)-2′-methyl-P-phenyl-5′-uridylyl-, 1-methylethyl ester
  • O3-[N-(Methoxycarbonyl)-L-methionyl]-[P(S),2’R]-2′-deoxy-2′-fluoro-3-(hydroxymethyl)-2′-methyl-P-phenyl-5′-uridylyl-L-alanine 1-methylethyl ester

[3-[(2R,3R,4R,5R)-3-fluoro-4-hydroxy-3-methyl-5-[[[[(2S)-1-oxo-1-propan-2-yloxypropan-2-yl]amino]-phenoxyphosphoryl]oxymethyl]oxolan-2-yl]-2,6-dioxopyrimidin-1-yl]methyl (2S)-2-(methoxycarbonylamino)-4-methylsulfanylbutanoate

antiviral, HEC 110114; Yiqibuvir, CHINA 2025, APPROVALS 2025, 82E4Q8WQV7

Encofosbuvir is a novel, oral small-molecule direct-acting antiviral (DAA) drug used to treat the hepatitis C virus (HCV). Approved by China’s National Medical Products Administration (NMPA) in March 2025, it serves as a core component of a domestic, pan-genotypic treatment regimen.

🔬 Mechanism of Action

Encofosbuvir works by targeting the machinery the virus needs to replicate itself:

  • Target Enzyme: It functions as an HCV NS5B RNA-dependent RNA polymerase inhibitor.
  • Viral Suppression: By selectively binding to this polymerase, it blocks the synthesis of viral RNA, effectively halting the replication and spread of the hepatitis C virus in mammals

Clinical Indications and Usage

According to the official regulatory updates from the China NMPA, encofosbuvir is prescribed under specific clinical parameters:

  • Combination Therapy: It must be used in combination with netanasvir (specifically netanasvir phosphate capsules).
  • Target Genotypes: The regimen is highly effective across multiple viral strains, covering HCV genotypes 1, 2, 3, and 6.
  • Patient Profile: It is indicated for adult patients who are treatment-naïve (never treated before) or who have been previously treated with interferon. It is safe for use in patients with or without compensated liver cirrhosis.

The drug is classified as a Class 1 innovative drug, representing a milestone in self-developed, domestic intellectual property:

  • Developers: It was jointly developed and brought to market by Sunshine Lake Pharma (a subsidiary of HEC Pharm) and YiChang HEC ChangJiang Pharmaceutical Co., Ltd.
  • Dosage Form: It is distributed commercially as 0.3g tablets.
  • Therapeutic Context: This medication expands the developer’s innovative hepatitis C pipeline, building upon their previously approved portfolio like emitasvir phosphate
  • OriginatorHEC Pharm; Sunshine Lake Pharma
  • DeveloperSunshine Lake Pharma
  • ClassAntivirals
  • Mechanism of ActionHepatitis C virus NS 5 protein inhibitors
  • RegisteredHepatitis C
  • 27 Mar 2025Registered for Hepatitis C (Combination therapy, Treatment-naive) in China (PO)
  • 08 Feb 2025Preregistered for Hepatitis C (Combination therapy, Treatment-experienced) in China (PO)
  • 08 Feb 2025Registered for Hepatitis C (Combination therapy, Treatment-experienced) in China (PO)

Encofosbuvir is an antiviral drug used to treat hepatitis C virus (HCV). In China, encofosbuvir is approved for use in combination with netanasvir for the treatment of adult patients with chronic HCV genotypes 1, 2, 3, or 6, who are either treatment-naive or have been previously treated with interferon.[1]

SYN

[0514]Example 3 

[0515](S)-(3-((2R,3R,4R,5R)-3-fluoro-4-hydroxy-5-((((S)-(((S)-1-isopropoxy-1-oxopropyl-2-yl)amino)(phenoxy)phosphoryl)oxy)methyl)-3-methyltetrahydrofuran-2-yl)-2,6-dioxo-2,3-dihydropyrimidin-1(6H)-yl)methyl-2-((methoxycarbonyl)amino)-4-(methylthio)butyrate

[0531]4) Synthesis of compound 3

Compound 3-6 (3.63 g, 4.2 mmol, 1 eq) was dissolved in acetone (12 mL), and water (9 mL), trifluoroacetic acid (3 mL), and glacial acetic acid (12 mL) were added sequentially at room temperature, followed by a reaction time of 2 hours. After the reaction was monitored by TLC until complete, 30 mL of dichloromethane was added to the reaction solution, stirred thoroughly, and allowed to stand for phase separation. The organic phase was washed sequentially with water (10 mL × 3), saturated sodium chloride (10 mL), dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. The solution was purified by column chromatography using DCM:MeOH = 50:1 as the eluent, yielding 2.8 g of a white foamy solid. 

[0534]MS-ESI: m/z 748.8[M+1] +; 

[0535]

1H NMR(400MHz,CDCl 3)δ7.49(d,J=8.2Hz,1H),7.34(d,J=7.6Hz,2H),7.24–7.16(m,3H),6.19(d,J=17.3Hz,1H),6.07–5.94(m,2H),5.75(d,J=8.3Hz,1H),5.41(d,J=7.4Hz,1H),5.07–4.95(m,1H),4.58–4.39(m,3H),4.12(d,J=8.6Hz,1H),4.02–3.80(m,4H),3.67(s,3H),2.52(t,J=7.5Hz,2H),2.14–1.90(m,5H),1.37(dd,J=18.4,14.3Hz,6H),1.24(d,J=6.3Hz,6H)。

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References

 “Netanasvir Phosphate Capsules Approved for Marketing by China NMPA”National Medical Products Administration. 2025-06-11.

Clinical data
Trade names英强布韦
Legal status
Legal statusRx in China
Identifiers
IUPAC name
CAS Number2232134-77-7
PubChem CID141522644
UNII82E4Q8WQV7
Chemical and physical data
FormulaC30H42FN4O13PS
Molar mass748.71 g·mol−1
3D model (JSmol)Interactive image
SMILES
InChI

//////////encofosbuvir, anax labs, antiviral, HEC 110114, Yiqibuvir, CHINA 2025, APPROVALS 2025, 82E4Q8WQV7

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Suricapavir


Suricapavir

CAS 2417270-21-2

MF C41H29ClF9N9O4S MF950.2 g/mol

N-[(1S)-1-[3-[4-chloro-3-(methanesulfonamido)-1-methylindazol-7-yl]-4-oxo-7-[6-(trifluoromethyl)-2-pyridinyl]quinazolin-2-yl]-2-(3,5-difluorophenyl)ethyl]-2-[(2S,4R)-9-(difluoromethyl)-5,5-difluoro-7,8-diazatricyclo[4.3.0.02,4]nona-1(6),8-dien-7-yl]acetamide

N-[(1S)-1-[3-[4-chloro-3-(methanesulfonamido)-1-methyl-indazol-7-yl]-4-oxo-7-[6-(trifluoromethyl)-2-pyridyl]quinazolin-2-yl]-2-(3,5-difluorophenyl)ethyl]-2-[(2S,4R)-9-(difluoromethyl)-5,5-difluoro-7,8-diazatricyclo[4.3.0.02,4]nona-1(6),8-dien-7-yl]acetamide

N-[(1S)-1-{(3P)-3-[4-chloro-3-(methanesulfonamido)-1-methyl-1Hindazol-7-yl]-4-oxo-7-[6-(trifluoromethyl)pyridin-2-yl]-3,4-
dihydroquinazolin-2-yl}-2-(3,5-difluorophenyl)ethyl]-2-[(3bS,4aR)-3-
(difluoromethyl)-5,5-difluoro-3b,4,4a,5-tetrahydro-1Hcyclopropa[3,4]cyclopenta[1,2-c]pyrazol-1-yl]acetamide
inhibitor of viral replication, antiviral, ZZ799EX5KN

tructurally resembles:

  • Lenacapavir-type macroheterocyclic capsid inhibitors (Gilead class)

PAT

Preparation of Example 59: N-((S)-1-((3P)-3-(4-chloro-1-methyl-3-(methylsulfonamido)-1H-indazol-7-yl)-4-oxo-7-(6-(trifluoromethyl)pyridin-2-yl)-3,4-dihydroquinazolin-2-yl)-2- (3,5-difluorophenyl)ethyl)-2-((3bS,4aR)-3-(difluoromethyl)-5,5-difluoro-3b,4,4a,5- tetrahydro-1H-cyclopropa[3,4]cyclopenta[1,2-c]pyrazol-1-yl)acetamide.

The title compound was prepared according to General Procedure D using 2-chloro-6-(trifluoromethyl)pyridine as the coupling partner. The experiment afforded the title compound, N-((S)-1-((3P)-3-(4-chloro-1-methyl-3-(methylsulfonamido)-1H-indazol-7-yl)-4-oxo-7-(6-(trifluoromethyl)pyridin-2-yl)-3,4-dihydroquinazolin-2-yl)-2-(3,5-difluorophenyl)ethyl)-2-((3bS,4aR)-3-(difluoromethyl)-5,5-difluoro-3b,4,4a,5-tetrahydro-1H-cyclopropa[3,4]cyclopenta[1,2-c]pyrazol-1-yl)acetamide. The sample was analyzed using LCMS Method F: retention time = 1.51 min.; observed ion = 948.4 (M-H).1H NMR (METHANOL-d4, 500 MHz) Shift 8.66 (s, 1H), 8.4-8.4 (m, 3H), 8.22 (t, 1H, J=7.9 Hz), 7.88 (d, 1H, J=7.7 Hz), 7.28 (br d, 1H, J=8.0 Hz), 7.20 (d, 1H, J=7.7 Hz), 6.7-6.8 (m, 1H), 6.61 (dd, 2H, J=2.2, 8.2 Hz), 6.67 (br t, 2H, J=54.7 Hz), 4.5-4.6 (m, 2H), 3.61 (s, 3H), 3.4-3.5 (m, 1H), 3.2-3.2 (m, 3H), 3.1-3.2 (m, 1H), 2.41 (br dd, 2H, J=3.7, 7.3 Hz), 1.34 (br d, 1H, J=5.4 Hz), 0.99 (br dd, 1H, J=1.9, 3.7 Hz)

PAT

WO 2020/084492 and WO 2020/254985 disclose certain Capsid Inhibitor compounds including the two compounds shown below which will be referred to in this application as the compounds of Formula la and Formula lb.

PAT

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///////////////suricapavir, ANAX, inhibitor of viral replication, antiviral, ZZ799EX5KN

Pixavir marboxil


Pixavir marboxil

CAS 2365473-17-0

MF C27H22F2N2O6S MW540.535

(1-((11S)-7,8-DIFLUORO-6,11-DIHYDROBENZO(C)(1)BENZOTHIEPIN-11-YL)-4,6-DIOXOSPIRO(2H-PYRIDO(1,2-B)PYRIDAZINE-3,1′-CYCLOPROPANE)-5-YL)OXYMETHYL METHYL CARBONATE

({1′-[(11S)-7,8-difluoro-6,11-dihydrodibenzo[b,e]thiepin-11-yl]-4′,6′-dioxo1′,2′,4′,6′-tetrahydrospiro[cyclopropane-1,3′-pyrido[1,2-b]pyridazin]-5′-yl}oxy)methyl methyl carbonate
antiviral, TG 1000, Yi Li Kang, SV42843XSX, Cap-dependent endonuclease-IN-1, Influenza virus infections, TaiGen Biotechnology

  • OriginatorTaiGen Biotechnology
  • Class3-ring heterocyclic compounds; Antivirals; Benzene derivatives; Carbonates; Cyclopropanes; Dibenzothiepins; Esters; Ethers; Fluorobenzenes; Organic sulfur compounds; Pyridazines; Pyridones; Small molecules; Spiro compounds
  • Mechanism of ActionEndonuclease inhibitors; Virus replication inhibitors
  • MarketedInfluenza virus infections
  • 27 Feb 2026Launched for Influenza virus infections (In adults, In adolescents) in China (PO), prior to February 2026 (TaiGen Biotechnology pipeline, February 2026)
  • 26 Jan 2026Pixavir marboxil licensed to Boryung Biopharma for commercialization in South Korea
  • 16 Dec 2025Chemical structure information added.

Pixavir marboxil (also known as TG-1000) is an investigational antiviral drug designed to treat and inhibit influenza virus infections. It belongs to a class of compounds known as cap-dependent endonuclease (CEN) inhibitors, which target a key viral enzyme necessary for influenza virus replication.


Mechanism of Action

  • Blocks viral replication: Pixavir marboxil works by inhibiting the influenza virus’s cap-dependent endonuclease, a part of the viral RNA polymerase complex the virus needs to “snatch” capped RNA fragments from host cell mRNA. Without this process, the virus cannot efficiently produce its own viral proteins or replicate.

What Viruses It Targets

Pixavir marboxil has shown activity against:

  • Influenza A viruses
  • Influenza B viruses
  • Certain drug-resistant influenza strains

This broad spectrum makes it useful for seasonal flu and potentially strains less responsive to older antiviral drugs

Clinical Development & Approval Status

Phase Trials & Results

  • Completed Phase III: Clinical trials in adults and adolescents (age ≥12) showed that a single dose shortened time to symptom relief compared to placebo (e.g., median ~60.9 h vs ~87.9 h).
  • Symptom relief benefits: The data indicated statistically significant improvement in flu symptoms and faster viral inactivation in treated patients versus placebo.
  • Pediatric Formulation: China’s health authority approved pediatric Phase III studies for Pixavir (children <12), indicating further development for younger patients.

Regulatory Filings

  • NDA (New Drug Application): Pixavir marboxil has been submitted for approval to the National Medical Products Administration (NMPA) in mainland China based on Phase III results.
  • Generic Name Approved: The drug has been officially recognized with the generic name “Pixavir marboxil,” moving it closer to commercialization.


Pixavir marboxil is a small molecule drug. The usage of the INN stem ‘-xavir’ in the name indicates that Pixavir marboxil is a influenza CAP-dependent endonuclease inhibitor. Pixavir marboxil has a monoisotopic molecular weight of 540.12 Da.

SYN

PAT

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Dezecapavir


Dezecapavir

CAS 2570323-59-8

MF C37H29ClF9N9O5S MW918.19

1H-Cyclopropa[3,4]cyclopenta[1,2-c]pyrazole-1-acetamide, N-[(1S)-1-[(3S)-3-[4-chloro-1-methyl-3-[(methylsulfonyl)amino]-1H-indazol-7-yl]-3,4-dihydro-4-oxo-7-(3,3,3-trifluoropropoxy)pyrido[2,3-d]pyrimidin-2-yl]-2-(3,5-difluorophenyl)ethyl]-3-(difluoromethyl)-5,5-difluoro-3b,4,4a,5-tetrahydro-, (3bS,4aR)-

N-[(1S)-1-[(3P)-3-[4-chloro-3-(methanesulfonamido)-1-methyl-1H-indazol-7-yl]-4-oxo-7-(3,3,3-
trifluoropropoxy)-3,4-dihydropyrido[2,3-d]pyrimidin-2-yl]-2-(3,5-difluorophenyl)ethyl]-2-[(3bS,4aR)-3-
(difluoromethyl)-5,5-difluoro-3b,4,4a,5-tetrahydro-1Hcyclopropa[3,4]cyclopenta[1,2-c]pyrazol-1-
yl]acetamide
inhibitor of viral replication, antiviral, SEK9LN2LSM, VH 4011499, VH4011499, VH-4011499, VH 499, GSK2838232, GSK 2838232

Dezecapavir is a potent experimental antiviral compound, specifically a novel HIV-1 capsid inhibitor, developed to block HIV replication by targeting the virus’s capsid protein, showing high effectiveness in lab settings (low nM range EC50) and representing a new class of drugs for HIV treatment, potentially for long-acting injectable therapies. It’s a complex molecule with a unique structure designed to disrupt the HIV capsid assembly, halting the virus’s life cycle early on. 

Key Characteristics:

  • Mechanism: Inhibits HIV-1 capsid assembly, a crucial step in the viral lifecycle.
  • Potency: Very effective in cell cultures, with a low nanomolar EC50 (effective concentration).
  • Class: Belongs to a new class of antivirals, distinct from integrase or reverse transcriptase inhibitors, offering a novel approach to HIV treatment.
  • Development: Under investigation, often mentioned as a potential candidate for long-acting injectable (LAI) treatments due to its potency. 

What it does:
Dezecapavir binds to the HIV capsid, preventing the virus from uncoating and maturing, thereby stopping new infections from forming. 

Significance:
It represents a promising new option for HIV treatment, especially in the context of growing resistance to existing drugs, and could be part of future long-acting regimens. 

SYN

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2020254985&_cid=P20-MKHOOT-76990-1

Preparation of Example 1: N-((S)-l-((3P)-3-(4-chloro-l-methyl-3-(methylsulfonamido)-lH- indazol-7-yl)-4-oxo-7-(3,3,3-trifluoropropoxy)-3,4-dihydropyrido[2,3-d]pyrimidin-2-yl)-2-(3,5- difluorophenyl)ethyl)-2-((3bSr4aR)-3-(difluoromethyl)-5r5-difluoro-3br4r4ar5-tetrahydro-lH- cyciopropa[3, 4]cydopenta[ l,2-c]pyrazoi-l-yi)acetamide

A solution of diisopropyl (E)-diazene-l,2-dicarboxylate (“DIAD”, 0.125 ml, 0.637 mmol) in THF (0.2 mL) was added dropwise to a mixture of N-(l-((3P)-3-(4-chloro-3-(N-(4-methoxybenzyl)methylsulfonamido)-l-methyl-lH-indazol-7-yl)-7-hydroxy-4-oxo-3,4-dihydropyrido[2,3-d]pyrimidin-2-yl)-2-(3,5-difluorophenyl)ethyl)-2-((3bS,4aR)-3-(difluoromethyl)-5,5-difluoro-3b,4,4a,5-tetrahydro-lH-cyclopropa[3,4]cyclopenta[l,2-c]pyrazol-l-yl)acetamide (0.2 g, 0.212 mmol)), 3,3,3-trifluoropropan-l-ol (0.073 g, 0.637 mmol) and triphenylphosphine (0.178 g, 0.679 mmol) in Tetrahydrofuran (2.1 mL) at rt. The reaction mixture was stirred for 18 h at rt and then was concentrated in vacuo. The residue was purified on silica gel (24 g RediSep Gold column) using a gradient of 0-60 % ethyl acetate in hexanes over 15 CV, and then holding at 60 % ethyl acetate in hexanes for 5 CV. Fractions containing the pure product were pooled and then concentrated to give a yellow solid. This solid was taken up in DCM (1 mL):TFA (0.5 mL); the solution was cooled to 0 °C; and to the solution was added triflic acid (0.057 mL, 0.637 mmol). The mixture was stirred for 1 h and then concentrated in vacuo. The residue was taken up in ethyl acetate; washed with 1 N

NaOH; washed with 0.5M citric acid; dried over Na2SC>4; filtered; and then was concentrated in vacuo. The residue was subjected to silica gel chromatography (24 g RediSep Gold column) using 0-60 % ethyl acetate in hexanes over 20 CV, then at 60 % ethyl acetate for 10 CV. Fractions containing the pure product were pooled and then concentrated in vacuoto give N-(l-((6P)-3-(4-chloro-l-methyl-3-(methylsulfonamido)-lH-indazol-7-yl)-4-oxo-7-(3,3,3-trifluoropropoxy)-3,4-dihydropyrido[2,3-d]pyrimidin-2-yl)-2-(3,5-difluorophenyl)ethyl)-2-((3bS,4aR)-3-(difluoromethyl)-5,5-difluoro-3b,4,4a,5-tetrahydro-lH-cyclopropa[3,4]cyclopenta[l,2-c]pyrazol-l-yl)acetamide (0.078 g, 0.081 mmol, 38.0 % yield) as a brown solid. *H NMR (500 MHz, METHANOL-d^ d ppm 8.46 – 8.53 (m, 1 H) 7.28 – 7.34 (m, 1 H) 7.19 – 7.24 (m, 1 H) 7.03 – 7.09 (m, 1 H) 6.53 – 6.81 (m, 4 H) 4.80 (dd, J=5.96, 2.98Hz, 3 H) 4.49 – 4.62 (m, 2 H) 3.58 – 3.62 (m, 3 H) 3.40 – 3.49 (m, 1 H) 3.22 – 3.24 (m, 3 H) 3.06 – 3.14 (m, 1 H) 2.80 – 2.89 (m, 2 H) 2.37 – 2.44 (m, 2 H) 1.32 – 1.37 (m, 1 H) 0.96 – 1.01 (m, 1 H). LCMS Analysis Method: Column = Acquity UPLC BEH C18, 2.1 x 100 mm, 1.7 pm particles; Injection Volume = 5.00 pL; Flowrate = 0.80 mL/min; Solvent A = 95:5

WatenMeCN w/ 0.1% v/v formic acid; Solvent B = 5:95 WatenMeCN w/ 0.1% v/v formic acid;

Elution profile = Start %B: 0, End %B: 100, Gradient Time: 3.5 min. then hold at 100% B for 1 min.; Detection wavelength 1 = 220 nm, wavelength 2 = 254 nm. LCMS retention time = 3.097 min; m/z = 918.05 [M+l]+.

PAT

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//////////dezecapavir, inhibitor of viral replication, antiviral, SEK9LN2LSM, VH 4011499, VH4011499, VH-4011499, VH 499, GSK2838232, GSK 2838232

Limnetrelvir


Limnetrelvir

CAS 2923500-04-1

MF C27H23F4N5O4 MW 557.50

N-[(3R)-1-[4-cyano-2-(morpholine-4-carbonyl)-6-(trifluoromethyl)phenyl]pyrrolidin-3-yl]-8-fluoro-2-oxo-1H-quinoline-4-carboxamide

N-{(3R)-1-[4-cyano-2-(morpholine-4-carbonyl)-6-
(trifluoromethyl)phenyl]pyrrolidin-3-yl}-8-fluoro-2-oxo1,2-dihydroquinoline-4-carboxamide
antiviral, ABBV-903, ABBV 903, 4TPS988XGG

Limnetrelvir (ABBV-903) is a MPro inhibitor. Limnetrelvir could be used in antiviral research.

SYN

https://patentscope.wipo.int/search/en/detail.jsf;jsessionid=4D458E543A941751578F87216FA39801.wapp1nA?docId=WO2024081351&_cid=P10-MJQJMM-46773-1#detailMainForm:MyTabViewId:PCTDESCRIPTION

Example 1 – Synthesis of Compound (2) (R)-N-(1-(4-cyano-2-(morpholine-4-carbonyl)-6-(trifluoromethyl)phenyl)pyrrolidin-3-yl)-8-fluoro-2-oxo-1,2-dihydroquinoline-4-carboxamide

Compound 2F – Synthesis of 8-fluoro-2-oxo-1,2-dihydroquinoline-4-carboxylic acid

[00035] A suspension of 7-fluoroindoline-2,3-dione (55 g, 333 mmol), malonic acid (41.6 g, 400 mmol) and sodium acetate (68.3 g, 833 mmol) in acetic acid (500 mL) was heated at 112 °C overnight. The reaction mixture was cooled to room temperature and poured into cold 0.4 M aqueous HCl (2200 mL). The precipitate was collected by filtration and rinsed thoroughly with ice-cold water (~250 mL) followed by methyl tert-butyl ether (~100 mL) and then concentrated twice from acetonitrile with high vacuum. The materials were largely dissolved into 1 M aqueous NaOH (370 mL) and filtered through diatomaceous earth with a 0.1 M aqueous NaOH (50 mL) rinse. Then the filtrate was washed thrice with dichloromethane (3 x 200 mL) which removed the color. After this aqueous layer was filtered again through diatomaceous earth, it was acidified by the dropwise addition of concentrated aqueous HCl (33 mL, ~0.4 moles). The material was collected by filtration. After prolonged drying under heat and vacuum, the material was treated with water (1 L) and the mixture was made acidic by the addition of a small amount of 1 M aqueous HCl. The suspension was heated to 80 °C and then allowed to slowly cool to room temperature. The resulting material was collected by filtration, washed with 0.01 M aqueous HCl (150 mL) and dried under vacuum at 80 °C to provide the title compound (2F).1H NMR (500 MHz, DMSO-d6) δ ppm 14.00 (bs, 1H), 12.07 (bs, 1H), 8.00 (dd, J = 8.2, 1.2 Hz, 1H), 7.49 (ddd, J = 11.0, 8.1, 1.2 Hz, 1H), 7.23 (ddd, J = 8.2, 8.1, 5.2 Hz, 1H), 6.95 (s, 1H); 13C NMR (101 MHz, DMSO-d6, 90 °C) δ ppm 165.75 – 165.73 (m), 160.30, 148.75 (d, J = 246.0 Hz), 140.85 – 140.80 (m), 128.11 (d, J = 13.7 Hz), 123.85, 121.60 – 121.53 (m), 121.53 – 121.43 (m), 117.70 – 117.65 (m), 115.33 (d, J = 17.2 Hz); 19F NMR (376 MHz, DMSO-d6, 90 °C) δ ppm -130.47 (dd, J = 10.9, 5.3 Hz); MS (APCI, M+H+) m/z 208.

Compound 2G – Synthesis of (R)-N-(1-(4-cyano-2-(morpholine-4-carbonyl)-6-(trifluoromethyl)phenyl)pyrrolidin-3-yl)-8-fluoro-2-oxo-1,2-dihydroquinoline-4-carboxamide (2)

00036] To a mixture of Compound 2F (29.84 g, 144 mmol) in anhydrous N,N-dimethylformamide (360 mL) was added DMTMM (4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-

methylmorpholinium chloride) (43.17 g, 156 mmol) over twelve minutes at room temperature. After the suspension had been stirred forty minutes, it was added over eight minutes to a suspension of Compound 2E (≤120 mmol) and N-methylmorpholine (16 mL, 146 mmol) in N,N-dimethylformamide (120 mL) with a N,N-dimethylformamide (20 mL) rinse. After forty minutes, the reaction mixture was added to rapidly stirred 0.1 M aqueous K2HPO4 (2.5 L) and extracted four times with 4:1 isopropyl acetate / heptanes then once with isopropyl acetate alone. The product, which had begun to precipitate out from the combined extracts, was separated by decantation and filtration, then washed with dichloromethane. The remaining aqueous phase was extracted twice more with isopropyl acetate and all the organic extracts were combined, then washed with additional 0.1 M aqueous K2HPO4 followed by water, dried (Na2SO4), and filtered. The filtrate was concentrated with the dichloromethane wash of the material collected above. The residue was concentrated, dissolved in acetonitrile / CH2Cl2, filtered, and purified by chromatography on silica (20 to 100% acetonitrile / CH2Cl2). The collected fractions were concentrated to a small volume, and stirred in ethyl acetate overnight.

[00037] The suspension was heated at 70 °C for twenty minutes, then allowed to slowly cool to room temperature. Methyl tert-butyl ether was stirred in, the suspension was cooled to 0 °C, and the purified product was collected by filtration with rinses of 1:1 ethyl acetate / methyl tert-butyl ether followed by methyl tert-butyl ether before being dried under vacuum with heat. The material obtained previously from the early extracts were also stirred in ethyl acetate, heated at 70 °C, then allowed to slowly cool to room temperature. Methyl tert-butyl ether was stirred in, the suspension was cooled to 0 °C, and the purified product was collected by filtration with rinses of 1:1 ethyl acetate / methyl tert-butyl ether rinse followed by methyl tert-butyl ether. The material was dried overnight under vacuum to provide the title compound (2).1H NMR (500 MHz, DMSO-d6) δ ppm 11.96 (s, 1H), 9.03 – 8.84 (m, 1H), 8.21 – 8.18 (m, 1H), 7.98 – 7.93 (m, 1H), 7.56 – 7.50 (m, 1H), 7.49 – 7.43 (m, 1H), 7.21 – 7.15 (m, 1H), 6.66 – 6.59 (m, 1H), 4.51 – 4.40 (m, 1H), 3.73 – 3.55 (m, 6H), 3.54 – 3.22 (m, 6H), 2.29 – 2.18 (m, 1H), 2.07 – 1.95 (m, 1H); 1H NMR (400 MHz, DMSO-d6, 90 °C) δ ppm 11.47 (bs, 1H), 8.77 – 8.47 (m, 1H), 8.09 (d, J = 2.1 Hz, 1H), 7.88 (d, J = 2.1 Hz, 1H), 7.54 (dd, J = 8.1, 1.2 Hz, 1H), 7.39 (ddd, J = 11.0, 8.1, 1.2 Hz, 1H), 7.15 (ddd, J = 8.1, 8.1, 5.1 Hz, 1H), 6.60 (s, 1H), 4.54 – 4.43 (m, 1H), 3.74 – 3.20 (m, 12H), 2.31 – 2.21 (m, 1H), 2.06 – 1.96 (m, 1H); 13C NMR (101 MHz, DMSO-d6, 90 °C) δ

ppm 166.61, 165.97, 161.31, 149.59 (d, J = 246.3 Hz), 148.95, 146.10 – 146.03 (m), 136.00, 135.65, 133.13 (q, J = 6.1 Hz), 128.84 – 128.63 (m), 123.76 (q, J = 273.7 Hz), 122.19, 122.16, 122.12, 121.60, 118.99 – 118.91 (m), 117.75, 116.17 (d, J = 17.3 Hz), 105.57, 66.04, 57.95, 51.06, 50.35, 47.74, 42.35, 31.54; 19F NMR (376 MHz, DMSO-d6) δ ppm -57.54 – -58.10 (m), -130.02 – -130.15 (m); 19F NMR (376 MHz, DMSO-d6, 90 °C) δ ppm -58.37 – -58.97 (m), -130.96 (dd, J = 11.0, 5.1 Hz). MS (APCI, M+H+) m/z 558.

PAT

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Iscartrelvir


Iscartrelvir

CAS 2921711-74-0

MF 2921711-74-0, 526.4 g/mol

N-{(1S,2R)-2-[4-bromo-2-(methylcarbamoyl)-6-nitroanilino]cyclohexyl}isoquinoline-4-carboxamide
antiviral, WU-04, WU 04, W2LTV65R5E

Iscartrelvir is an investigational new drug developed by the Westlake University for the treatment of COVID-19. It targets the SARS-CoV-2 3CL protease, which is crucial for the replication of the virus responsible for COVID-19.[1][2]

Iscartrelvir is a small molecule drug. The usage of the INN stem ‘-trelvir’ in the name indicates that Iscartrelvir is a antiviral 3CL protease inhibitor. Iscartrelvir has a monoisotopic molecular weight of 525.1 Da.

PAT

WO2022150962A1

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2022150962&_cid=P11-MJKTXT-76321-1

SYN

https://patentscope.wipo.int/search/en/detail.jsf?docId=CN331401594&_cid=P11-MJKTO7-65334-1

PAT

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2024243841&_cid=P11-MJKTO7-65334-1

N-((1S,2R)-2-((4-bromo-2-(methylcarbamoyl)-6-nitrophenyl)amino)cyclohexyl)isoquinoline-4-carboxamide, and its structure is as follows:

Example 1: Preparation of Compound 1 

[0189]A free, amorphous compound 1, a yellow solid, was prepared according to the method disclosed in paragraphs [00121]-[00128] of WO2022150962A1, and was used in the following examples. The specific synthetic steps are shown in steps a to d:

The reagents and conditions for steps a to d are further described below: (a) 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU), N,N-diisopropylethylamine (DIPEA), CH₂Cl₂ 

or 

dichloromethane (DCM), 0°C, 2 h; (b) DIPEA, dimethylformamide (DMF), 80°C, 16 h; (c) 3M ethyl hydrochloride (HCl·EA), CH₂Cl₂ , 

h ; (d ) HATU, DIPEA, DMF, room temperature, 12 h. 

[0191]Step a: Synthesis of N-methyl-5-bromo-2-fluoro-3-nitrobenzamide (I-1) 

[0192]A solution of 5-bromo-2-fluoro-3-nitrobenzoic acid (0.8 g, 3.80 mmol) in dichloromethane (20 mL) was stirred at 0 °C. Then, HATU (2.0 g, 5.25 mmol), DIPEA (1.88 mL, 11.4 mmol), and methylamine hydrochloride (0.31 g, 4.5 mmol) were added to the reaction mixture. The mixture was stirred at 0 °C for 2 hours until it became clear. The mixture was extracted three times with dichloromethane, and the combined organic layers were washed with a saturated brine solution. The organic phase was then dried over anhydrous Na₂SO₄ and concentrated 

under vacuum. Finally, the mixture was purified by chromatography to give compound I-1 (0.8 g, 76% yield) as a yellow solid.

[0193]Step b: Synthesis of tert-butyl 2-((4-bromo-2-(methylcarbamoyl)-6-nitrophenyl)amino)cyclohexyl)carbamate (I-2) 

[0194]A solution of compound I-1 (0.8 g, 2.9 mmol) in 15 mL of DMF was stirred at room temperature. Then, tert-butyl ((1S,2R)-2-aminocyclohexyl)carbamate (0.75 g, 3.5 mmol) (the corresponding stereoisomer of this reagent can be used to synthesize the stereoisomer of compound I-2) and DIPEA (1.44 mL, 8.7 mmol) were added to the reaction mixture. The mixture was heated to 80 °C and stirred for 16 hours. The mixture was extracted three times with ethyl acetate, and the combined organic layers were washed with saturated salt solution. The organic phase was then dried over anhydrous Na₂SO₄ and concentrated under vacuum to give compound 

I -2 as a yellow solid, requiring no further purification.

Step c: Synthesis of 2-(2-aminocyclohexyl)amino)-5-bromo-N-methyl-3-nitrobenzamide hydrochloride (I-3) 

[0196]A solution of compound I-2 (90 mg, 0.19 mmol) (or the corresponding stereoisomer) in anhydrous dichloromethane (6 mL) was stirred at room temperature. Then, HCl (4 mL, 3 M in ethyl acetate) was added. The mixture was stirred at room temperature for 2 hours. The mixture was concentrated under vacuum to give compound I-3 as a yellow solid, requiring no further purification. 

[0197]Step d: Synthesis of N-((1S,2R)-2-((4-bromo-2-(methylcarbamoyl)-6-nitrophenyl)amino)cyclohexyl)isoquinoline-4-carboxamide 

[0198]At room temperature, a solution of the corresponding isoquinoline-4-carboxylic acid (1 equivalent) and HATU (1.5 equivalent) in anhydrous DMF (6 mL) was stirred. Then, compound I-3 and DIPEA (5.0 equivalent) were added. The mixture was stirred overnight at room temperature. The mixture was extracted three times with ethyl acetate, and the combined organic layers were washed with saturated brine. The organic phase was then dried over anhydrous Na₂SO₄ and 

concentrated under vacuum. Finally, the mixture was purified by chromatography to give compound 1 as a free amorphous solid in yellow form.

PAT

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Clinical data
Other namesWPV01; WU-04
Identifiers
IUPAC name
CAS Number2921711-74-0
PubChem CID156774920
ChemSpider129307041
UNIIW2LTV65R5E
PDB ligandJ7R (PDBeRCSB PDB)
Chemical and physical data
FormulaC24H24BrN5O4
Molar mass526.391 g·mol−1
3D model (JSmol)Interactive image
SMILES
InChI

References

  1.  Yang L, Wang Z (September 2023). “Bench-to-bedside: Innovation of small molecule anti-SARS-CoV-2 drugs in China”European Journal of Medicinal Chemistry257 115503. doi:10.1016/j.ejmech.2023.115503PMC 10193775PMID 37229831.
  2.  Hou N, Shuai L, Zhang L, Xie X, Tang K, Zhu Y, et al. (February 2023). “Development of Highly Potent Noncovalent Inhibitors of SARS-CoV-2 3CLpro”ACS Central Science9 (2): 217–227. doi:10.1021/acscentsci.2c01359PMC 9885526PMID 36844503.
  3. Resistance mechanisms of SARS-CoV-2 3CLpro to the non-covalent inhibitor WU-04Publication Name: Cell DiscoveryPublication Date: 2024-04-09PMCID: PMC11003996PMID: 38594245DOI: 10.1038/s41421-024-00673-0
  4. Identification of Ebselen derivatives as novel SARS-CoV-2 main protease inhibitors: Design, synthesis, biological evaluation, and structure-activity relationships explorationPublication Name: Bioorganic & Medicinal ChemistryPublication Date: 2023-12-15PMID: 37972434DOI: 10.1016/j.bmc.2023.117531
  5. The molecular mechanism of non-covalent inhibitor WU-04 targeting SARS-CoV-2 3CLpro and computational evaluation of its effectiveness against mainstream coronavirusesPublication Name: Physical chemistry chemical physics : PCCPPublication Date: 2023-09-13PMID: 37655706DOI: 10.1039/d3cp03828a
  6. Bench-to-bedside: Innovation of small molecule anti-SARS-CoV-2 drugs in ChinaPublication Name: European Journal of Medicinal ChemistryPublication Date: 2023-09-05PMCID: PMC10193775PMID: 37229831DOI: 10.1016/j.ejmech.2023.115503
  7. Development of Highly Potent Noncovalent Inhibitors of SARS-CoV-2 3CLproPublication Name: ACS Central SciencePublication Date: 2023-01-25PMCID: PMC9885526PMID: 36844503DOI: 10.1021/acscentsci.2c01359

////////iscartrelvir, antiviral, WU-04, WU 04, W2LTV65R5E