Methanol → 9-benzyloxy-6-(2-bromo-4-chlorobenzyl)-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione

Participants

Reaction Steps

To a stirred solution of 5-benzyloxy-2-(2-bromo-4-chlorobenzyl)-6-hydroxypyrimidine-4-carboxylicacid(2-hydroxyethyl)-isopropylamide (379) (1.0 g, 1.873 mmol) and triphenyl phosphine (1.717 g, 6.554 mmol) in dichloromethane (120 mL), diisopropyl azodicarboxylate (1.114, 5.618 mmol) was added over 10 h (dilution 0.19 M; rate 3 ml/h) at 0° C. The reaction was monitored by silica thin layer chromatography (3% methanol in dichloromethane; Rf=0.4). After completion of the reaction, 50 mL water were added and the mixture was extracted with dichloromethane (2×100 mL). The organic part was dried over sodium sulphate and concentrated. The resulting crude product was column purified (using amine bound silica) to get 9-benzyloxy-6-(2-bromo-4-chlorobenzyl)-2-isopropyl-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (380) (0.406 g, 41.95%) as a white solid.

Provenance & Evidence