Über das Tetrahydrospiro [cyclohexan-1,2′(1′H)-chinazolin]-4′(3′H)-on - Über Heterocyclen, 23. Mitt.

Abstract

The product obtained by heating cyclohexanone with urea has been found to be 5′. 6′. 7′. 8′-tetrahydrospiro[cyclohexane-1.2′(1′H)-quinazoline]-4′(3′H)-one, not cyclohexylidene-2-carbamoylcyclohex-1-enylamine, as was previously assumed1. Compounds with analogous structures were formed by heating cyclopentanone or cycloheptanone with urea. Characteristic features of this class of compounds, i.e. β-carbamoyl enamines, are the enhanced reactivities of the nuclear 4 a′-position and of the methylene group in the peri-position to NH-1′. © 1970 Springer-Verlag.