Über die Darstellung von substituierten 3,4-Dihydro-2(1 H )-pyrimidin-iminen und 2-Aminopyrimidinen aus Guanidin und α,β-ungesättigten Ketonen

摘要: Guanidine reacts with the 2-alken-1-ones4 a-f and5 to give unstable dihydropyrimidinimines (or-amines respectively)8 (I, II or III respectively) and hexahydroquinazolinimine (-amine)9 III);8 lose H2, partly in course of reaction, during recrystallization yield 2-pyrimidinamines10 a-c, e, f, 4-methyl-5,6,7,8-tetrahydro-2-quinazolinamine11. With picric acid compounds8 d, f and9, resp. are converted into stable 2-amino-3,4-dihydro-1H-2-pyrimidinylium picrates12 d 2-amino-4-methyl-3,5,6,7,8,8 a-hexahydro-1H-2-quinazolinium picrate (13 resp.14, 15)18, whereas8 e HCl chloride12 e. The structures of12 d-f follow from their NMR-spectra, of10 and11 by alternative syntheses known methods12–17 (e.g. β-diketones guanidine). reaction of8 and9 to10 respectively is compared previously described dehydrogenation disproportionation reactions, especially 3,4-dihydro-2(1H)-pyrimidinones (6 d 4,23 20) and-thiones (30 1) similar structure formulated as a base-catalysed elimination H2.