RING-CHAIN TAUTOMERISM OF 2-ARYL-6-OXOHEXAHYDROPYRIMIDINE-4-CARBOXYLIC ACID SODIUM SALTS
It was shown by 1 H and 13 C NMR spectroscopy that the 2-aryl-6‑oxohexahydropyrimidine-4-carboxylic acid sodium salts existed in D 2 O solution as a tautomeric mixture of cyclic and linear forms. The cyclic form consisted of two (2 RS ,4 S )-stereoisomers, differing in the aryl substituent configuration at the pyrimidine ring C-2 atom. Authors: A. Yu. Ershov, D. G. Nasledov, K. V. Nasonova, K. V. Sezyavina, T. V.  Susarova, I. V. Lagoda, and V. V. Shamanin English Translation in Chemistry of Heterocyclic Compounds , 2013, 49 (4), pp 598-603 http://link.springer.com/article/10.1007/s10593-013-1287-0