EXOTIC AMINO ACIDS. 4. SYNTHESIS OF METHYL ESTERS OF SOME N-HETEROAMINOMETHYLENEMALONIC ACIDS

Abstract

Isopropylidene N-hetarylaminomethylenemalonates, obtained from isopropylidene ethoxymethylenemalonate and 2-aminopyridine, 2-amino-5-methylpyridine, 2-aminopyrimidine, 7-amino-4-methylcoumarin, and 2-amino-3,5-diethoxycarbonyl-4-methylthiophene, undergo methanolysis at room temperature to give methyl esters of the corresponding N-hetarylaminomalonic acids. Isopropylidene N hetarylaminomethylenenemalonate, containing a 2-aminothiazole group as a heterocyclic substituent, does not react under analogous conditions, but cyclizes upon heating at reflux to give 5-oxo-5H-thiazolo[3,2-a]pyrimidine-6-carboxylic acid. 4-Oxo-9-R-4H-pyridino[1,2-a]pyrimidines are obtained upon the sublimation of isopropylidene N-pyridyl- and N-5-methylpyridylaminomethylenemalonates.

Authors: D. Zicane, I. Ravinya, Z. Tetere, I. Rijkure, E. Gudriniece, and U. Kalejs.

English Translation in Chemistry of Heterocyclic Compounds, 2000, 36 (6), pp 754-757

http://link.springer.com/article/10.1007/BF02297688