Trifluoroacetic acid → 5-Methyl-1-phenyl-1,2-dihydro[1,4]oxazino[2,3,4-jk]carbazol-7-ol

Participants

Reaction Conditions

Reaction Steps

To 5-methyl-1-phenyl-1,2,9,10-tetrahydro[1,4]oxazino[2,3,4-jk]carbazol-7(8H)-one (9.0 g, 28.4 mmol) in ethyl acetate/acetonitrile (150 mL/50 mL) is added trifluoroacetic acid (4 mL) and anhydrous cupric chloride (9.7 g, 56.7 mmol). The mixture is heated to reflux at 90° C. for 7 h. The mixture is poured into methylene chloride (500 mL) and filtered to remove inorganic solids. The filtrates are washed with saturated potassium carbonate solution followed by water, dried over magnesium sulfate and concentrated. The residue is dissolved in DMF (20 mL) to which is added lithium bromide (4.2 g, 56.7 mmol) and lithium carbonate (4.9 g, 56.7 mmol). The mixture is heated at 119° C. for 5 h, then partitioned between water and CH2Cl2. The organic layer is washed twice with brine (30 mL). Column chromatography (200 g silica gel) using EtOAc/hexanes (20/80) as eluent gave 1.3 g (14.5%) of 5-methyl-1-phenyl-1,2-dihydro[1,4]oxazino[2,3,4-jk]carbazol-7-ol.

Provenance & Evidence