Trimethoprim
Title: Trimethoprim
CAS Registry Number: 738-70-5
CAS Name: 5-[(3,4,5-Trimethoxyphenyl)methyl]-2,4-pyrimidinediamine
Additional Names: 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidine
Trademarks: Instalac (Virbac); Monotrim (Duphar); Proloprim (Wellcome); Syraprim (Wellcome); Tiempe (DDSA); Trimanyl (Tosse); Trimogal (Lagap); Trimopan (Berk); Trimpex (Roche); Uretrim (Bastian); Wellcoprim (Wellcome)
Molecular Formula: C14H18N4O3
Molecular Weight: 290.32
Percent Composition: C 57.92%, H 6.25%, N 19.30%, O 16.53%
Literature References: Prepn from guanidine and b-ethoxy-3,4,5-trimethoxybenzylbenzalnitrile: Stenbuck, Hood, US 3049544 (1962 to Burroughs Wellcome); Hoffer, US 3341541 (1967 to Hoffmann-La Roche). Improved synthesis: B. Roth et al., J. Med. Chem. 23, 379, 535 (1980). Toxicity data: Yamamoto et al., Chemotherapy (Tokyo) 21, 187 (1973). Review: Burchall in Antibiotics vol. 3, J. W. Corcoran, F. E. Hahn, Eds. (Springer-Verlag, New York, 1975) pp 304-320. Comprehensive description: G. J. Manius, Anal. Profiles Drug Subs. 7, 445-475 (1978). Review of antibacterial activity, pharmacokinetics and therapeutic use: R. N. Brogden et al., Drugs 23, 405-430 (1982).
Properties: White to cream, bitter crystalline powder, mp 199-203°. Soly in g/100 ml at 25°: DMAC 13.86; benzyl alcohol 7.29; propylene glycol 2.57; chloroform 1.82; methanol 1.21; water 0.04; ether 0.003; benzene 0.002. pKa 6.6. LD50 orally in mice: 7000 mg/kg (Yamamoto).
Melting point: mp 199-203°
pKa: pKa 6.6
Toxicity data: LD50 orally in mice: 7000 mg/kg (Yamamoto)
NOTE: See Sulfamethoxazole, Sulfadiazine, Sulfametrole, Sulfamoxole, and Sulfalene for lists of trade names of mixtures with Trimethoprim.
Therap-Cat: Antibacterial.
Therap-Cat-Vet: Antibacterial.
Keywords: Antibacterial (Synthetic); 2,4-Diaminopyrimidines.

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