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

Temperature

90 °C

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.

1. temperatureThe mixture is heated
2. filtrationfiltered
3. customto remove inorganic solids
4. washThe filtrates are washed with saturated potassium carbonate solution
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated
7. dissolutionThe residue is dissolved in DMF (20 mL) to which
8. temperatureThe mixture is heated at 119° C. for 5 h
9. custompartitioned between water and CH2Cl2
10. washThe organic layer is washed twice with brine (30 mL)

ORD record

ord-04e24e47ffd64a4bbcc39a07ab898ec0

Source dataset

uspto-grants-2002_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06448397B1