Региоселективное хлорирование этилового эфира 6-(5-метил-2-оксо-4-имидазолин-4-ил)-6-оксогексановой кислоты. Новый синтез биотина

Regioselective chlorination of a methyl group in ethyl 6-(6-methyl-4-imidazolin-2-on-4- yl)-6-oxohexanoate with sulfuryl chloride in methylene chloride has been performed for the first time. The synthesis of 5-(2,3-dihydro-1H-thieno[3, 4-d]imidazol-2-on-4-yl)pentanoic acid methyl and ethyl esters (tetrahydrobiotin esters) - key compounds in biotin (vitamin H) synthesis - has been developed proceeding from f 6-(5-chloromethyl-4-imidazolin-2-on-4-yl)-6-oxohexanoic acid esters.