Direct Chemoselective Synthesis of N-3-Substituted Pyrimidinones in a Microwave-Assisted Method

Caesium carbonate promoted regioselective O-functionalization of 4,6-diphenylpyrimidin-2(1H)-ones under mild conditions and mechanistic insight

“…16 Alkylation of pyrimidin-2(1H)-ones with alkyl halides predominantly produced N-alkylated products. 8,17 Hopkins et al studied the ambident anion chemistry of 2-hydroxypyrimidines for their alkylation towards various alkyl halides and alkali salts. The alkylation reactions were found to favour the nitrogen site and N to O ratio for the substitution was found to be insensitive to the nature of alkali metal.…”

Synthesis of Pyrimido[1,2-a]indolediones and Pyrimidinediones via [4+2] Annulation of 2H-Azirine-2-carbaldehydes

“…The second strategy was the silver-catalyzed insertion of isocyanates into the N–O bond of isoxazol-5-ones to form imides, followed by Mumm rearrangement to produce 6-substituted pyrimidinediones (Scheme B-b) . The third strategy was Kundu’s method using β-carbonylester precursors and urea derivatives under microwave irradiation (Scheme B-c) . The fourth method was condensation of 1,3-oxazin-6-one and amine under reflux conditions (Scheme B-d) .…”

“…11 The third strategy was Kundu's method using β-carbonylester precursors and urea derivatives under microwave irradiation (Scheme 1Bc). 12 The fourth method was condensation of 1,3-oxazin-6-one and amine under reflux conditions (Scheme 1B-d). 13 Despite these reports, the development of an efficient intermolecular method for accessing 6-substituted pyrimidinediones has always been the subject of intensive ongoing research.…”