Diisopropylethylamine → 4-(6-Oxo-1,6-dihydro-pyrimidin-4-yl)-piperazine-1-carboxylic acid benzyl ester

Participants

Reaction Steps

A mixture of 6-chloro-3H-pyrimidin-4-one (36984-063-A; 3.90 g, 29.9 mmol), benzyl 1-piperaz-inecarboxylate (Aldrich; 8.81 g, 40.0 mmol), and diisopropylethylamine (7.0 mL, 40.2 mmol) in 2-butanol (100 mL) was heated in a 250 mL round-bottomed flask equipped with a reflux condenser in an oil-bath at about 80° C. (oil-bath temperature) for 8 hours. The heating bath was removed and the reaction mixture was left standing at room temperature overnight. The white solid was filtered off, washed with 2-butanol, and air-dried to give 4-(6-oxo-1,6-dihydro-pyrimidin-4-yl)-piperazine-1-carboxylic acid benzyl ester (7.76 g, 83%) as a white powder, mp 247-249° C. 1H NMR (d6-DMSO) δ 1.39 (s, 9H), 3.45-3.50 (m, 8H), 5.08 (s, 2H), 5.26 (s, 1H), 7.28-7.38 (m, 5H), 7.90 (s, 1H), 11.66 (br s, 1H).

Provenance & Evidence