Antitumor Imidazotetrazines. 35. New Synthetic Routes to the Antitumor Drug Temozolomide
摘要:
Three new pathways to the antitumor drug temozolomide (4) have been explored via intermediates 3, 6, and 7. The key intermediate 5-amino-1-(N-methylcarbamoyl)imidazole-4-carboxamide (6) has been successfully converted to 4 in 45% yield by employing sodium nitrite in aqueous tartaric acid at 0-5 degrees C, Compound 6 is prepared from nitrophenyl carbamate 14a and methylamine or directly from 5-aminoimidazole-4-carboxamide (13) and either methyl isocyanate or N-methylcarbamoyl chloride. Temozolomide (4) is also prepared from 8-cyano-3-methylimidazo[5,1-d]-1,2,3,5-tetrazin-4(3H)-one (7) by hydrolysis to the hydrochloride salt of 4 in 10 M hydrochloric acid. Compound 7 is prepared from either 5-diazoimidazole-4-carbonitrile (28) and methyl isocyanate or by diazotization of 5-amino-1-(N-methylcarbamoyl)imidazole-4-carbonitrile (25). Attempts to cyclize 5-(3-methyltriazen-1-yl)imidazole-4-carboxamide (3) with phosgene or phosgene equivalents were unsuccessful: only 2-azahypoxanthine (11) was isolated.
Described is a new process for producing temozolomide, comprising the reaction between 5-aminoimidazole-4-carboxamide and N-succinimidyl-N′-methyl carbamate and the subsequent reaction of the thus obtained carbamoyl 5-aminoimidazole-4-carboxamide with sodium nitrite. Temozolomide is then purified by chromatography on adsorbent polymeric resin and subsequent crystallization from water and acetone.
This invention relates to a novel process for the synthesis of temozolomide, an antitumor compound, and to intermediates useful in this novel process.
本发明涉及一种合成抗肿瘤化合物替莫唑胺的新工艺以及在该新工艺中有用的中间体。
Process for the preparation of temozolomide and analogs
申请人:Pathi Srinivas Laxminarayan
公开号:US20090326028A1
公开(公告)日:2009-12-31
A process for the preparation of compounds of formula IA, where R═CH
3
(i.e. temozolomide):
comprising diazotizing a compound of the formula IIA:
where in R is as defined above in the presence of at least one metal halide, an acid and a source of nitrous acid, followed by conversion of acidic solution containing temozolomide. The conversion can be carried out by a liquid-liquid extraction technique in a water immiscible solvent. The temozolomide may be further purified in an acetone-water mixture.
An improved process for the isolation of temozolomide
申请人:CIPLA LIMITED
公开号:EP2374807A2
公开(公告)日:2011-10-12
The present invention relates to a process for isolating temozolomide from an acidic solution containing temozolomide comprising; subjecting the acidic solution of temozolomide to a counter-current continuous liquid-liquid extraction using water immiscible solvent. The present invention also relates to a process for purifying temozolomide comprising refluxing temozolomide in an acetone-water mixture having a pH from 2.5 to 4.5 followed by recovering purified temozolomide.