(3-Chlorophenyl)hydrazine → 4-chloro-3,3-dimethyl-2,3-dihydro-1H-indole

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Reaction Steps

Step 1 of the synthesis of 2-chloro-1-(6-chloro-3,3-dimethyl-2,3-dihydro-indol-1-yl)-ethanone (Preparation 1) was repeated, using 3-chlorophenylhydrazine (1.0 g, 5.6 mmol) and the two isomers separated by chromatography on silica gel (gradient elution, 0-60% EtOAc/petrol then 0-100% Et2O/petrol), to give 6-chloro-3,3-dimethyl-2,3-dihydro-1H-indole (38 mg, 4%) as a yellow oil, 1H NMR (CDCl3): 6.93 (1H, d), 6.71 (1H, dd), 6.61 (1H, d), 3.34 (2H, s), 1.31 (6H, s) and 4-chloro-3,3-dimethyl-2,3-dihydro-1H-indole (146 mg, 14%), as a yellow oil, 1H NMR (Me-d3-OD): 6.93 (1H, t), 6.58 (1H, d), 6.53 (1H, d), 3.27 (2H, s), 1.43 (6H, s).

Provenance & Evidence