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({(12’aR)-12′-[(11S)-7,8-difluoro-6,11-dihydrodibenzo[b,e]thiepin-11-yl]-6′,8′-dioxo-6′,8′,12′,12’a-tetrahydro-1’H,4’H-spiro[cyclopropane-1,3′-[1,4]oxazino[3,4-c]pyrido[2,1-f][1,2,4]triazin]-7′-yl}oxy)methyl methylcarbonate antiviral, GP 681, Jiangxi Qingfeng Pharmaceutical, influenza A, INFLUENZA B, Cap-dependent endonuclease-IN-3, A72V8WPZ9F
Suraxavir marboxil (GP681) is an oral antiviral prodrug developed by Jiangxi Qingfeng Pharmaceutical for treating acute, uncomplicated influenza A and B virus infections.
Key Details
Mechanism of Action: It converts into its active metabolite, GP1707D07, which acts as a cap-dependent endonuclease (CEN) inhibitor by targeting the polymerase acidic (PA) protein subunit of the influenza virus RNA polymerase. This stops viral gene transcription and replication.
Administration: Designed as a single-dose oral therapy (typically evaluated at 40 mg).
Efficacy: In phase 3 clinical trials, a single dose administered within 48 hours of symptom onset reduced the median time to symptom alleviation to 42.0 hours (compared to 63.0 hours for placebo) and rapidly lowered viral load.
Safety Profile: Adverse events are mostly mild to moderate and comparable to placebo, with low rates of acquired resistance (such as I38T PA variants).
Mechanism of ActionRNA-dependent RNA polymerase inhibitors
RegisteredInfluenza virus infections
28 Nov 2025Capital Medical University initiates enrolment in a phase III trial for Influenza virus infections (In children, In adults, In the elderly) in China (PO) (NCT07236814)
01 Aug 2025Jiangxi Kerui Pharmaceutical plans a phase III trial for Influenza virus infections (In Children) in August 2025 (PO, suspension) (NCT07113392)
Preparation of Compound of formula (10): Compound of formula (11) (388 mg, 1 mmol) was dissolved in 3 mL dichloromethane and added with 1 mL trifluoroacetic acid, and the mixture was stirred at room temperature for 3 hours. TLC showed the reaction was complete, and the mixture was added with 3N sodium hydroxide solution to adjust pH=9-10. The mixture was extracted with dichloromethane, and organic phases were merged, washed with saturated salt solution, dried, and concentrated to give 270 mg solid, which was directly used in the next step.
Preparation of Compound of formula (8): Compound of formula (9) (1.0 g, 7.8 mmol) was dissolved in 10 mL anhydrous tetrahydrofuran, and dropwise added with 2.5M n-butyllithium solution (3.1 mL, 7.8 mmol) slowly at −78° C. and under nitrogen protection. After addition, the mixture was stirred and reacted at the temperature for 2 hours. Then allyl formate (0.94 g, 7.8 mmol) was dropwise added. After addition, the mixture was stirred and reacted for 2 hours, and TLC showed the raw materials were substantially completely reacted, and then the reaction mixture was poured into saturated ammonium chloride solution to quench, and then extracted with ethyl acetate (15 mL×3). The organic phases were merged, dried over anhydrous sodium sulfate, and concentrated to dry to give 1.65 g oily product.
Preparation of Compound of formula (7): Compound of formula (8) (1.65 g, 7.8 mmol) was dissolved in 15 mL anhydrous tetrahydrofuran, and dropwise added with 1M diisobutylaluminum hydride solution (11.7 mL, 11.7 mmol) slowly at −78° C. and under nitrogen protection. After addition, the mixture was stirred and reacted at the temperature for 2 hours. TLC showed the raw materials were substantially completely reacted, and then the reaction mixture was poured into saturated potassium sodium tartrate solution to quench, and then extracted with ethyl acetate (20 mL×3). The organic phases were merged, dried over anhydrous sodium sulfate, and concentrated to dry to give 1.57 g oily product.
Preparation of Compound of formula (6): Compound of formula (7) (1.57 g, 7.4 mmol) was dissolved in 15 mL methanol, and p-toluenesulfonic acid monohydrate (140 mg, 0.74 mmol) was added, and the mixture was stirred at room temperature overnight. TLC showed the raw materials were substantially completely reacted, and then the mixture was added with saturated sodium bicarbonate solution to adjust to be neutral, and concentrated. The residue was separated by column chromatography to give 0.86 g yellow oily product.
Preparation of Compound of formula (5): Compound of formula (10) (270 mg, 0.94 mmol) and Compound of formula (6) (255 mg, 1.13 mmol) were dissolved in 5 mL acetonitrile. 1M solution of tin tetrachloride in dichloromethane (1.4 mL, 1.41 mmol) was added dropwise under nitrogen protection and at −20° C. After addition, the mixture was stirred and reacted at the temperature for 3 hours. The mixture was added with saturated sodium bicarbonate solution, stirred for 30 min, and stood to layer, and the aqueous phase was extracted with dichloromethane. The organic phases were merged, washed with saturated salt solution, dried, and concentrated to give 428 mg crude product.
Preparation of Compound of formula (4): Compound of formula (5) (428 mg, 0.89 mmol) was dissolved in 5 mL tetrahydrofuran, and tetrakis(triphenylphosphine)palladium (104 mg, 0.09 mmol) and morpholine (774 mg, 8.9 mmol) were added and reacted at room temperature for 2 hours. The reaction was shown complete through TLC spot plate analysis. The mixture was concentrated, and the residue was separated by column chromatography to give 216 mg product.
Preparation of Compound of formula (3): Compound of formula (4) (216 mg, 0.61 mmol) and Compound of formula (12) (242 mg, 0.92 mmol) were reacted at 100° C. for 3 hours in 3 mL solution of T 3P in ethyl acetate under airtight condition. The mixture was cooled, diluted with saturated NaHCO3, and then extracted with ethyl acetate. The organic phases were merged, dried and concentrated, and separated by column chromatography to give 200 mg crude product, which was separated by chiral column to give 40 mg product.
Preparation of Compound of formula (2): Compound of formula (3) (40 mg, 0.067 mmol) and lithium chloride (20 mg, 0.48 mmol) were reacted at 100° C. for 3 hours in 1 mL DMA. After the reaction finished, the mixture was diluted with 10 mL water, and added with 2N hydrochloric acid to adjust pH to 3-4. The mixture was filtered, and the solid was pumped to dry to give 25 mg product. 1HNMR (400 MHz, CDCl 3) δ: 7.05-7.15 (m, 5H), 6.85 (m, 1H), 6.70 (d, 1H, J=7.6 Hz), 5.78 (d, 1H, J=7.6 Hz), 5.3 (m, 2H), 4.69 (d, 1H, J=6.8 Hz), 4.17 (d, 1H, J=14 Hz), 4.09 (d, 1H, J=14 Hz), 3.90 (m, 1H), 3.69 (m, 1H), 3.44 (d, 1H, J=15.2 Hz), 0.95 (m, 1H), 0.74 (m, 3H); ESI-MS m/z (M+H) + 510.1.
Preparation of Compound of formula (1): Compound of formula (2) (40 mg, 0.08 mmol), chloromethyl methyl carbonate (25 mg, 0.2 mmol), potassium carbonate (28 mg, 0.2 mmol) and potassium iodide (3 mg, 0.02 mmol) were reacted at 60° C. for 5 hours in 1 mL N,N-dimethylacetamide. The reaction was shown complete through TLC spot plate analysis, the mixture was added with water to quench, and added with 1N diluted hydrochloric acid to adjust pH to 3-4. The solid was filtered, dried, and separated by column chromatography to give 35 mg product, which was the compound of formula (1), and the solid was analyzed to be amorphous and used as the starting material for preparing various crystal forms in subsequent embodiments. 1HNMR (400 MHz, DMSO-d6) δ: 7.40-7.42 (m, 2H), 7.25 (d, 1H, J=7.6 Hz), 7.15 (m, 1H), 7.10 (m, 1H), 7.00 (d, 1H, J=7.2 Hz), 6.84 (t, 1H, J=7.6 Hz), 5.75 (m, 4H), 5.43 (d, 1H, J=16.4 Hz), 4.57 (dd, 1H, J=3.2, 9.6 Hz), 3.96-4.03 (m, 3H), 3.73 (s, 3H), 3.51 (t, 1H, J=10.0 Hz), 3.41 (s, 1H), 0.75 (t, 2H, J=8.4 Hz), 0.50 (m, 2H); ESI-MS m/z (M+H) + 598.1.
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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