Oxazepam → 7-Chloro-3-fluoro-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one

Beteiligte Stoffe

Reaktionsschritte

A well stirred suspension of 10 g (0.03 mol) of 3-hydroxy-1,3-dihydro-7-chloro-5-phenyl-2H-1,4-benzodiazepin-2-one and 500 ml of methylene chloride was cooled to -70°. Diethylaminosulfur trifluoride (25 ml, 0.2 mol) was then added dropwise with exclusion of moisture and air. On completion of the addition the dry-ice acetone bath was removed, the contents of the flask were allowed to warm up in about 25 minutes to -10° and the reaction then immediately quenched by pouring into a beaker containing 400-500 ml of ice water. (If the reaction mixture is allowed to warm to 25°, none of the desired product is obtained.) Vigorous stirring of the ice water mixture continued for 7 to 10 minutes. The organic layer was separated, dried over MgSO4 and evaporated under reduced pressure to give a light orange powder. The product was dissolved in hot benzene, treated with decolorizing charcoal and filtered hot. On addition of heptane to the benzene solution, followed by cooling in ice, 3-fluoro-1,3-dihydro-7-chloro-5-phenyl-2H-1,4-benzodiazepin-2-one crystallized out as a white powder, 8.19 g (82%): mp 190°-192° (decom.); 19F nmr (DMSO-d6) δ -161.5 ppm (d, d, J=56, 4 Hz, 1H), 1H nmr (DMSO-d6) δ 7.2-7.8 (m, 8H), δ 5.72 (d, J=56 Hz, 1H), δ 11.0 ppm (N--H).

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