N,N-Dimethylcyclohexylamine → 6-chloro-N-(3-methylbutan-2-yl)-1,1-dioxo-4H-thieno[3,2-e][1,2,4]thiadiazin-3-amine

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Reaction Conditions

Reaction Steps

Phosphorus pentoxide (2.84 g; 20 mmol), N,N-dimethylcyclohexylamine (5 ml, 33 mmol) and 1,2-dimethylpropylamine hydrochloride (2.47 g; 20 mmol) were carefully mixed in a three necked flask equipped with mechanical stirring and condenser with drying tube. The mixture was heated on an oil bath at 200° C. until a homogeneous mass was obtained. Then 6-chloro-2,3-dihydro-3-oxo-4H-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxide (1.2 g; 5 mmol) was added and the mixture was stirred at 240° C. for 45 min. The mixture was allowed to cool to about 100° C., 150 ml of water was added and stirring was continued at ambient temperature for approximately 1 h. The hydrolysed mixture was filtered and the dark precipitate was washed with water and dissolved in boiling ethanol, treated with charcoal, filtered and finally evaporated to dryness. Flash chromatography (ethyl acetate/silica gel) afforded 105 mg (7%) of the pure title compound; m.p. 216°-218° C.; 1H-NMR (DMSO-d6): δ 0.90 (d, 6H, CH(CH3)2), 1.08 (d, 3H, NCHCH3), 1.75 (m, 1H, CH(CH3)2), 3.65 (m, 1H, NHCH), 7.11 (br. s, 2H, 5-H+NH), 10.68 (s, 1H, NH); MS m/e: 307/309 (M+).

Provenance & Evidence