Dimethyl Sulfide → 3-Oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazine-6-carbaldehyde

Reaction equation

[CH:1]([C:9]1[CH:10]=[CH:11][C:12]2[O:13][CH2:14][C:15](=[O:19])[NH:16][C:17]=2[N:18]=1)=CC1C=CC=CC=1.[O:20]=[O+][O-].S(C)C>C(Cl)Cl>[O:19]=[C:15]1[CH2:14][O:13][C:12]2[CH:11]=[CH:10][C:9]([CH:1]=[O:20])=[N:18][C:17]=2[NH:16]1

Participants

Procedure

To a solution of 6-styryl-4H-pyrido[3,2-b][1,4]oxazin-3-one (757 mg, 3.00 mmol) in CH2Cl2 (128 mL) was bubbled ozone at −78° C. with stirring until a pale blue color appeared. The excess ozone was removed by bubbling oxygen through the reaction mixture for 15 min. Me2S (1.0 mL, 14 mmol) was added, and the reaction was stirred at −78° C. for 3 h and then at RT for 24 h. The solvent was concentrated and the residue was triturated with Et2O (100 mL). The solid collected from filtration of the suspension was washed with additional Et2O and dried in vacuo to provide 340 mg (63% crude) of a solid, which was used without further purification. MS (ESI): exact mass calculated for C8H6N2O3, 178.04; m/z found, 179.2 [M+H]+.