Synthesis of new polyfunctional 5,6,7,8-tetrahydroimidazo-[1,5-c]pyrimidin-5-ones by the aza-Wittig reaction followed by intramolecular cyclization and 1,3-prototropic shift

Ethyl 2-oxo-6-[(triphenyl-λ⁵-phosphanylidene)aminomethyl]-1,2,3,4-tetrahydropyrimidine-5-carboxylates reacted with organic isocyanates according to the aza-Wittig pattern, and the subsequent intramolecular ring closure and 1,3-H shift resulted in the formation of ethyl 3-alkyl(aryl)amino-5-oxo-5,6,7,8-tetrahydroimidazo[1,5-c]pyrimidine-8-carboxylates.

Lebed’ P. S.; Kos P. O.; Polovinko V. V.; Tolmachev A. A.; Vovk M. V.
Russ. J. Org. Chem. 2009, 45 (6), 921-927
DOI: 10.1134/S1070428009060207