Lawesson's reagent → 3-(Benzyloxy)-N,9,9-trimethyl-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)-N,9,9-trimethyl-4-oxo-4,6,7,9-tetrahydropyrimido[2,1-c][1,4]oxazine-2-carboxamide (0.40 g, 1.17 mmol, 1.0 equiv) in THF (12 mL) under a nitrogen atmosphere, was added Lawesson's reagent (0.28 g, 0.70 mmol, 0.6 equiv). The yellow solution was then heated to 50° 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 (20-100% ethyl acetate/hexane) to provide the title compound (0.38 g, 90% yield) as a yellow solid. 1H NMR (400 MHz, CDCl3) δ ppm 8.19 (s, 1H), 7.45-7.57 (m, 2H), 7.29-7.42 (m, 3H), 5.25 (s, 2H), 3.93-4.12 (m, 4H), 3.17 (d, J=5.04 Hz, 3H), 1.62 (s, 6H); LCMS (ES+, (M+H)+) m/z 360.19.

Provenance & Evidence