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Skeletal formula of diiodohydroxyquinoline
ChemSpider 2D Image | Diiodohydroxyquinoline | C9H5I2NO



  • Molecular FormulaC9H5I2NO
  • Average mass396.951 Da
  • NSC-8704
  • SS-578

8-Quinolinol, 5,7-diiodo-
ثنائي إيودوهيدروكسيكينوليين[Arabic][INN]
 IodoquinolCAS Registry Number: 83-73-8 
CAS Name: 5,7-Diiodo-8-quinolinol 
Additional Names: diiodohydroxyquin; diiodo-oxyquinoline; 5,7-diiodo-8-hydroxyquinoline 
Manufacturers’ Codes: SS-578 
Trademarks: Diodoquin (Searle); Disoquin; Floraquin (Searle); Dyodin; Dinoleine; Searlequin; Diodoxylin; Rafamebin; Ioquin (Abbott); Direxiode (Delalande); Stanquinate; Yodoxin (Searle); Zoaquin; Enterosept; Embequin (M & B) 
Molecular Formula: C9H5I2NO, Molecular Weight: 396.95 
Percent Composition: C 27.23%, H 1.27%, I 63.94%, N 3.53%, O 4.03% 
Literature References: Prepd by the action of iodine monochloride on 8-hydroxyquinoline: Papesch, Burtner, J. Am. Chem. Soc.58, 1314 (1936); by the action of KIO3 on 8-hydroxyquinoline: Zeifman, C.A.34, 3745. Electrolytic prepn: Brown, Berkowitz, Trans. Electrochem. Soc.75, 385 (1939). See also Claus, DE78880; Passek, DE411050; Matsumura, C.A.21, 1461 (1927); Pirrone, Cherubino, C.A.28, 3073 (1934).Properties: Crystals from xylene. The medicinal grade is a yellowish-brown powder. mp 200-215° (extensive decompn). Almost insol in water. Sparingly sol in alcohol, ether, and acetone; sol in hot pyridine and in hot dioxane. 
Melting point: mp 200-215° (extensive decompn) 
Therap-Cat: Antiamebic. 
Keywords: Antiamebic. 

The quinoline derivative diiodohydroxyquinoline (INN), or iodoquinol (USAN), can be used in the treatment of amoebiasis.[1]

It is poorly absorbed from the gastrointestinal tract and is used as a luminal amebicide. It acts by chelation of ferrous ions essential for metabolism.[2]

It was discovered by Adco Co. and introduced as diiodohydroxyquinoline.[3]

Susceptibility of Dientamoeba fragilis has been measured.[4]

Iodoquinol is an amebocide used against Entamoeba histolytica, and it is active against both cyst and trophozoites that are localized in the lumen of the intestine. It is considered the drug of choice for treating asymptomatic or moderate forms of amebiasis. The full mechanism of action is unknown. Iodoquinol is used for diseases caused by moderate intestinal amebiasis.

Diodoquin enhances zinc absorption in the zinc deficiency disorder Acrodermatitis enteropathica, probably because Diodoquin act as a zinc ionophore.[5]

5,7-Diiodo-8-quinolinol Chemical


Diiodohydroxyquinoline,Adco Co.




GABA prodrug


It acts as an amoebicidal and so used in the treatment of amoebiasis, balantidiasis (an infection caused by protozoa).


Iodoquinol (diiodohydroxyquin, Yodoxin, Moebiquin) is a halogenated 8-hydroxyquinoline derivative whose precise mechanism of action is not known but is thought to involve an inactivation of essential parasite enzymes. Iodoquinol kills the trophozoite forms of E. histolytica, B. coli, B. hominis, and Dientamoeba fragilis.
Iodoquinol is absorbed from the gastrointestinal tract and is excreted in the urine as glucuronide and sulfate conjugates. Most of an orally administered dose is excreted in the feces. Iodoquinol has a plasma half-life of about 12 hours.
Iodoquinol is the drug of choice in the treatment of asymptomatic amebiasis and D. fragilis infections. It is also used in combination with other drugs in the treatment of other forms of amebiasis and as an alternative to tetracycline in the treatment of balantidiasis.
Adverse reactions are related to the iodine content of the drug; the toxicity is often expressed as skin reactions, thyroid enlargement, and interference with thyroid function studies. Headache and diarrhea also occur. Chronic use of clioquinol, a closely related agent, has been linked to a myelitislike illness and to optic atrophy with permanent loss of vision.

Manufacturing Process

5,7-Diiodo-8-quinolinol widely used as an intestinal antiseptic, especially as an antiamebic agent. It is also used topically in other infections and may cause CNS and eye damage. It is known by very many similar trade names worldwide.
0.01 mol 8-oxychinoline and 0.01 mol salicylic acid were dissolved in 500 ml of water and then 0.05 mol potassium iodide was added. The mixture was heated to temperature 90°-100°C. After that 0.01 mol of KIO3 by little tiles was added. The next tile was added after a disappearence of discharging iodine. Then 10 ml 2 N HCl was added. The solid product was fallen, filtered off, washed with hot water and in 0.25 N NaOH dissolved. The solution was filtered and the clear filtrate precipitated with a very little excess of HCl. The product 5,7-diiodo-8-quinolinol was filtered, washed with hot water and dried. MP: 200°-250°C (with decomposition).

brand name

Quinadome (Bayer); Yodoxin (Glenwood).

Therapeutic Function


Clinical Use

5,7-Diiodo-8-quinolinol, 5,7-diiodo-8-hydroxyquinoline,or diiodohydroxyquin (Yodoxin, Diodoquin, Diquinol) is ayellowish to tan microcrystalline, light-sensitive substancethat is insoluble in water. It is recommended for acute andchronic intestinal amebiasis but is not effective in extraintestinaldisease. Because a relatively high incidence of topicneuropathy has occurred with its use, iodoquinol should notbe used routinely for traveler’s diarrhea.

Safety Profile

Poison by ingestion and intravenous routes. Human systemic effects by ingestion: eye effects. Mutation data reported. When heated to decomposition it emits very toxic fumes of Iand Nox

Chemical Synthesis

Iodoquinol, 5,7-diiodo-8-quinolinol (37.2.2), is made by iodination of 8-oxyquinoline (37.2.1) using a mixture of potassium iodide/potassium iodate. The initial 8-hydroxyquinolin (37.2.1) is made from 2-aminophenol and glycerol in the presence of sulfuric acid and nitrobenzene (Skraup synthesis).

Purification Methods

It crystallises from xylene and is dried at 70o in a vacuum. [Beilstein 21 II 58.]

5,7-Diiodo-8-quinolinol synthesis


Synthesis of 5,7-Diiodo-8-quinolinol from 8-Hydroxyquinoline


DE 411050 DOI: 10.1021/ja01298a506

File:Iodoquinol synthesis.svg


Iodoquinol, 5,7-diiodo-8-quinolinol (37.2.2), is made by iodination of 8-oxyquinoline (37.2.1) using a mixture of potassium iodide/potassium iodate. The initial 8-hydroxyquinolin (37.2.1) is made from 2-aminophenol and glycerol in the presence of sulfuric acid and nitrobenzene (Skraup synthesis) [39,40]

Iodoquinol is an amebocide used against E. histolytica, and it is active against both cysts and trophozoites that are localized in the lumen of the intestine. It is considered the drug of choice for treating asymptomatic or moderate forms of amebiasis. The mechanism of action is unknown. Iodoquinol is used for diseases caused by moderate intestinal amebiasis. Synonyms of this drug are diquinol, iodoxin, diiodoquin, amebaquin, and others

39. F. Passek, Ger. Pat. 411.050 (1925). 40. V. Papesch, R.R. Burtner, J. Am. Chem. Soc., 58, 1314 (1936).

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  1. ^ Ghaskadbi S, Vaidya VG (March 1989). “In vivo antimutagenic effect of ascorbic acid against mutagenicity of the common antiamebic drug diiodohydroxyquinoline”. Mutat. Res222 (3): 219–22. doi:10.1016/0165-1218(89)90137-7PMID 2493578.
  2. ^ Nagata, Noriyuki; Marriott, Deborah; Harkness, John; Ellis, John T.; Stark, Damien (2012). “Current treatment options for Dientamoeba fragilis infections”International Journal for Parasitology: Drugs and Drug Resistance2: 204–215. doi:10.1016/j.ijpddr.2012.08.002ISSN 2211-3207PMC 3862407PMID 24533282.
  3. ^ Publishing, William Andrew (2013-01-15). Pharmaceutical Manufacturing Encyclopedia (3rd ed.). Elsevier Science. p. 1312. ISBN 9780080947266.
  4. ^ Chan FT, Guan MX, Mackenzie AM, Diaz-Mitoma F (May 1994). “Susceptibility testing of Dientamoeba fragilis ATCC 30948 with iodoquinol, paromomycin, tetracycline, and metronidazole”Antimicrob. Agents Chemother38 (5): 1157–60. doi:10.1128/aac.38.5.1157PMC 188168PMID 8067755.
  5. ^ Aggett, P.J.; Delves, H.T.; Harries, J.T.; Bangham, A.D. (March 1979). “The possible role of Diodoquin as a zinc ionophore in the treatment of acrodermatitis enteropathica”. Biochemical and Biophysical Research Communications87 (2): 513–517. doi:10.1016/0006-291X(79)91825-4PMID 375935.
Preferred IUPAC name5,7-Diiodoquinolin-8-ol
Other namesDiquinol, iodoxin, diiodoquin, amebaquin
CAS Number83-73-8 
3D model (JSmol)Interactive image
ECHA InfoCard100.001.362 
PubChem CID3728
CompTox Dashboard (EPA)DTXSID6023155 
Chemical formulaC9H5I2NO
Molar mass396.951
ATC codeG01AC01 (WHO)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
<img src="; alt="<sup>1</sup>H NMR spectrum of C<sub>9</sub>H<sub>5</sub>I<sub>2</sub>N<sub></sub>O<sub></sub> in CDCL3 at 400 MHz.

//////////////IODOQUINOL, Diiodohydroxyquinoline, NSC-8704, SS-578






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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 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, 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...... , 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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