SYNTHESIS AND INVESTIGATION OF THE STABILITY OF ESTERS OF 6'-CARBAMOYLMETHYLTHIO-5'-CYANO-1',4'-DIHYDRO-3,4'- AND -4,4'-BIPYRIDINE-3'-CARBOXYLIC ACIDS. 1. ESTERS OF 6'-CARBAMOYLMETHYLTHIO-5'-CYANO-1',4'-DIHYDRO-3,4'-BIPYRIDINE-3'-CARBOXYLIC ACIDS

Abstract

Esters of 6'-carbamoylmethylthio-5'-cyano-1',4'-dihydro-3,4'-bipyridine-3'-carboxylic acids  are obtained by the alkylation of piperidinium 3'-alkoxycarbonyl-5'-cyano-1',4'-dihydro-3,4'-bipyridine-6'-thiolates with iodoacetamide. For an HPLC study of the stability of solutions of the abovementioned 1,4-dihydrobipyridines (solution pH 2.3-9.0) the  appropriate esters of 6'-carbamoylmethylthio-5'-cyano-3,4'-bipyridine-3'-carboxylic acids and esters of 8-cyano-5-methyl(or phenyl)-3-oxo-7-pyridin-3-yl-2,3-dihydro-7H-thiazolo[3,2-a]pyridine-6-carboxylic acids were synthesized as reference compounds. Analysis by HPLC was carried out under  conditions of reverse-phase chromatography. It was shown that solutions of the investigated compounds in a mixture of acetonitrile and phosphate buffer  (pH 3.0-5.0) were stable for 1 month on storage protected  from  light. Under the action of light in all the solutions investigated irrespective of pH the formation occurs of the corresponding esters of 6'-carbamoylmethylthio-5'-cyano-3,4'-bipyridine-3'-carboxylic acids. The presence of esters of 8-cyano-5-methyl(or phenyl)-3-oxo-7-pyridin-3-yl-2,3-dihydro-7H-thiazolo[3,2-a]pyridine-6-carboxylic acids (no more  than 4%) was detected only in 0.1% solutions of phosphoric acid (pH 2.3) under conditions of storage of the latter protected from light. A series  of as  yet  unidentified products was detected in solutions of pH 7.0-9.0.

How to Cite
Kažoka, H.; Krauze, A.; Viļums, M.; Černova, L.; Sīle, L.; Duburs, G.  Chem. Heterocycl. Compd. 2007, 43, 50. [Khim. Geterotsikl. Soedin. 2007, 59.]

For this article in the English edition see DOI 10.1007/s10593-007-0007-z