116693-22-2Relevant academic research and scientific papers
SYNTHESIS OF TETRAHYDROPYRIMIDINES WITH 2-OXOALKYL GROUPS USING PYRIMIDINIUM SALTS AND ENOL SILYL ETHERS : FORMATION OF DIAZABICYCLONONA-3,6-DIENE DERIVATIVES
Yamamoto, Yohsuke,Sakaguchi, Akira,Yoshida, Hiroshi,Akiba, Kin-ya
, p. 725 - 732 (2007/10/02)
Reactions of N-silyl- or N-acyl-pyrimidinium salts with enol trimethylsilyl ethers were carried out to afford the adducts with a 2-oxoalkyl group, that is, 2-hydroxy-4-(2-oxoalkyl)-1,2,3,4-tetrahydro-pyrimidines (9) or the 3-acyl derivatives (8), respectively.Monoacylation of compounds (9) gave monoamides (8) in high yields.Exhaustive acylation of diamines (9) with a large excess of 2,2,2-trichloroethyl chloroformate in the presence of pyridine gave bicyclic compounds, 2-oxa-8,9-diazabicyclonona-3,6-dienes (14).By addition of trifluoroacetic acid, compounds (14) were reopened to afford 3,4-dihydropyrimidinium salts (11'), which were subjected to nucleophilic attack to give 1,2,3,4-tetrahydopyrimidines (16) in high yield.
