Lawesson's reagent → 3-(Benzyloxy)-9,9-dimethyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carbothioamide

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-(benzyloxy)-9,9-dimethyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxamide (0.54 g, 1.64 mmol, 1.0 equiv) in THF (33 mL) under a nitrogen atmosphere, was added Lawesson's reagent (0.40 g, 0.98 mmol, 0.6 equiv). The yellow solution was then heated to 70° C. (oil bath). After stirring for 1 h, the reaction was cooled to ambient temperature and concentrated in vacuo. The crude product was purified by silica gel chromatography (30-100% ethyl acetate/hexane) to provide the title compound (0.28 g, 49% yield) as a pale yellow solid. 1H NMR (400 MHz, CDCl3) δ ppm 8.04 (s, 1H), 7.63 (s, 1H), 7.50-7.57 (m, 2H), 7.27-7.41 (m, 3H), 5.30 (s, 2H), 3.96-4.08 (m, 4H), 1.62 (s, 6H); LCMS (ES+, (M+H)+) m/z 346.17.

Provenance & Evidence