Title: Cycloguanil
CAS Registry Number: 516-21-2
CAS Name: 1-(4-Chlorophenyl)-1,6-dihydro-6,6-dimethyl-1,3,5-triazine-2,4-diamine
Additional Names: 4,6-diamino-1-(p-chlorophenyl)-1,2-dihydro-2,2-dimethyl-s-triazine; 2,4-diamino-1-p-chlorophenyl-1,6-dihydro-6,6-dimethyl-1,3,5-triazine; 1-p-chlorophenyl-2,4-diamino-6,6-dimethyl-1,6-dihydro-1,3,5-triazine; chlorazine (Russian); chlorguanide triazine; TCl
Manufacturers' Codes: M-10580; D-20
Molecular Formula: C11H14ClN5
Molecular Weight: 251.72
Percent Composition: C 52.49%, H 5.61%, Cl 14.08%, N 27.82%
Literature References: Metabolic product formed from the antimalarial drug chlorguanide: Carrington et al., Nature 168, 1080 (1951). Prepn: Modest et al., J. Am. Chem. Soc. 74, 855 (1952); Loo, ibid. 76, 5096 (1954); Carrington et al., J. Chem. Soc. 1954, 1017; Bami, J. Sci. Ind. Res. 14C, 231 (1955); Modest, J. Org. Chem. 21, 1 (1956); US 2900385 (1959 to Children's Cancer Res. Found.); Elslager, Worth, US 3074947 (1963 to Parke, Davis).
Properties: Prisms from chloroform + ether, mp 146°. uv max (water): 241 nm (log e 4.11).
Melting point: mp 146°
Absorption maximum: uv max (water): 241 nm (log e 4.11)
Derivative Type: Hydrochloride
Molecular Formula: C11H14ClN5.HCl
Molecular Weight: 288.18
Percent Composition: C 45.85%, H 5.25%, Cl 24.60%, N 24.30%
Properties: Prisms from water, mp 210-215°. uv max (water): 241 nm (log e 4.12).
Melting point: mp 210-215°
Absorption maximum: uv max (water): 241 nm (log e 4.12)
Derivative Type: Dihydrochloride
Molecular Formula: C11H14ClN5.2HCl
Molecular Weight: 324.64
Percent Composition: C 40.70%, H 4.97%, Cl 32.76%, N 21.57%
Properties: Crystals from acetone, mp 190-196°.
Melting point: mp 190-196°
Derivative Type: Pamoate
CAS Registry Number: 609-78-9
Additional Names: Cycloguanil embonate
Manufacturers' Codes: CI-501
Trademarks: Camolar (Parke-Davis)
Molecular Formula: (C11H14ClN5)2.C23H16O6
Molecular Weight: 891.80
Percent Composition: C 60.61%, H 4.97%, Cl 7.95%, N 15.71%, O 10.76%
Properties: Yellow crystals, mp 231-234°. Soly in water: 0.003%.
Melting point: mp 231-234°
Therap-Cat: Antimalarial.
Keywords: Antimalarial.
Cycloheptanone Cyclohexanecarboxylic Acid Cyclohexanol Cyclohexanone Cyclohexene

Cycloguanil sf.png
Systematic (IUPAC) name
Clinical data
Legal status  ?
CAS number 516-21-2
ATC code P01BB02
PubChem CID 9049
ChemSpider 8697 YesY
Chemical data
Formula C11H14ClN5 
Mol. mass 251.715 g/mol
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Cycloguanil is a dihydrofolate reductase inhibitor,[1] and is a metabolite of the antimalarial drug proguanil; its formation in vivo has been thought to be primarily responsible for the antimalarial activity of proguanil.[2] However, more recent work has indicated that, while proguanil is synergistic with the drug atovaquone (as in the combination Malarone), cycloguanil is in fact antagonistic to the effects of atovaquone, suggesting that, unlike cycloguanil, proguanil may have an alternative mechanism of antimalarial action besides dihydrofolate reductase inhibition.[3]

Although cycloguanil is not currently in general use as an antimalarial, the continuing development of resistance to current antimalarial drugs has led to renewed interest in studying the use of cycloguanil in combination with other drugs.[4]