O=[C:2]1[C:8]2[CH:9]=[CH:10][CH:11]=[CH:12][C:7]=2[CH2:6][O:5][C:4]2[CH:13]=[CH:14][C:15]([CH2:17][CH2:18][C:19]([OH:21])=[O:20])=[CH:16][C:3]1=2>C(O)(=O)C.[Zn]>[CH:16]1[C:3]2[CH2:2][C:8]3[CH:9]=[CH:10][CH:11]=[CH:12][C:7]=3[CH2:6][O:5][C:4]=2[CH:13]=[CH:14][C:15]=1[CH2:17][CH2:18][C:19]([OH:21])=[O:20]A solution of 3-(6,11-dihydro-11-oxo-dibenz[b,e]oxepin-2-yl)propanoic acid (6.0 g) in 120 ml glacial acetic acid was treated with zinc dust (18.0 g) in portions over 1 minute. This slurry was heated at reflux for 2 hours then filtered while hot through a sintered funnel. The filtrate was evaporated, taken up in ethyl acetate and washed with dilute HCl, then dried and evaporated to a solid. This solid was recrystallized from ethyl acetate to give 4.3 g of crystals, m.p. 181-183° C.
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