SYNTHESIS OF 6'-CARBAMOYLMETHYLTHIO-5'-CYANO-1',4'-DIHYDRO-3,4'-BIPYRIDINE-3'-CARBOXYLIC AND 6'-CARBAMOYLMETHYLTHIO-5'-CYANO-1',4'-DIHYDRO-4,4'-BIPYRIDINE-3'-CARBOXYLIC ESTERS AND INVESTIGATION OF THEIR STABILITY. 2. ESTERS OF 6'-CARBAMOYLMETHYLTHIO-5'-CYANO-1',4'-DIHYDRO-4,4'-BIPYRIDINE-3-CARBOXYLIC ACIDS

Abstract

The stability of solutions of esters of 6′-carbamoylmethylthio-5′-cyano-2′-methyl-1′,4′-dihydro-4,4′-bi-pyridine-3′-carboxylic acids was investigated by HPLC. The corresponding esters of 6′-carbamoyl-methylthio-5′-cyano-4,4′-bipyridine-3′-carboxylic acids, esters of 8-cyano-5-methyl-3-oxo-7-(4-pyridyl)-2,3-dihydro-7H-thiazolo-[3,2-a]pyridine-6-carboxylic acids, methyl  3-amino-2-carbamoyl-6-methyl-4-(4-pyridyl)-4,7-dihydrothieno[2,3-b]pyridine-5-carboxylate, and methyl 3-amino-2-carbamoyl-6-methyl-4-(4-pyridyl)-thieno[2,3-b]pyridine-5-carboxylate were synthesized as standard compounds (typical impurities). Analysis by HPLC was realized under  the conditions of reverse-phase chromatography. It was established that solutions of the investigated compounds (with mixtures of acetonitrile with phosphate buffer, having pH values of not less than 3 and not more than 5, as solvents) are stable for one month when the solutions are stored in a place protected against light. It is also necessary to use chromatographic systems in which the aqueous components have pH 3-5 during determination of the purity of the esters of 6′-carbamoylmethylthio-5′-cyano-2′-methyl-1′,4′-dihydro-4,4′-bipyridine-3′-carboxylic acid by HPLC in order to separate the analyzed sorbates and their typical impurities more completely. 

How to Cite
Kažoka, H.; Krauze, A.; Viļums, M.; Černova, L.; Sīle, L.; Duburs, G.  Chem. Heterocycl. Compd. 2007, 43, 708. [Khim. Geterotsikl. Soedin. 2007, 841.]

For this article in the English edition see DOI 10.1007/s10593-007-0115-9