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

HRID 390335Notes

Reaction equation

[CH2:1]([O:8][C:9]1[C:18](=[O:19])[N:17]2[C:12]([C:13]([CH3:21])([CH3:20])[O:14][CH2:15][CH2:16]2)=[N:11][C:10]=1[C:22]([NH2:24])=O)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.COC1C=CC(P2(SP(C3C=CC(OC)=CC=3)(=S)S2)=[S:34])=CC=1>C1COCC1>[CH2:1]([O:8][C:9]1[C:18](=[O:19])[N:17]2[C:12]([C:13]([CH3:21])([CH3:20])[O:14][CH2:15][CH2:16]2)=[N:11][C:10]=1[C:22](=[S:34])[NH2:24])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

Conditions

Temperature: 70 °C

Procedure

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.

Workup

temperaturethe reaction was cooled to ambient temperature
concentrationconcentrated in vacuo
customThe crude product was purified by silica gel chromatography (30-100% ethyl acetate/hexane)

Sources & evidence

ORD record: ord-925b465a6c284fa7831915e848c9dd12
Source dataset: uspto-grants-2013_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08383639B2

Reaction notes

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