Rhodium
(Chief Bee)
10-04-02 07:53
No 364213
      Nitrostyrene to phenetylamine, NaBH4/RaneyNi/N2H4
(Rated as: excellent)
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A nitrostyrene is reduced with sodium borohydride in methanol to the phenylnitroethane in 53% yield, followed by catalytic transfer hydrogenation using Raney Nickel and hydrazine hydrate to give the phenethylamine in 83% yield.

4-Benzyloxy-5-Bromo-3-Methoxy-phenyl-beta-nitroethane

4-Benzyloxy-5-Bromo-3-Methoxy-beta-nitrostyrene (3.5g) in 70ml methanol was cooled to 0C, and 0.7g NaBH4 was added portionwise during 30 min, and the mixture stirred at room temp for 2h. The solvent was evaporated in vacuo, water added and the product extracted with CHCl3, washed with water, dried over sodium sulfate and the solvent evaporated. The crude product was isolated in 53% yield (1.85g, mp 62C) after column chromatography over silica, eluent benzene/hexane 1:1.

4-Benzyloxy-5-Bromo-3-Methoxy-phenethylamine

To a solution of 1.6g in 40ml methanol was added 1.6g Raney Nickel and 1.6ml hydrazine hydrate and the mixture shaken at ambient temperature for one hour. The resulting mixture on usual workup gave the title amine as an oil (1.2g, 83%). Oxalate salt mp 189-190C.

Reference: Indian Journal of Chemistry, Vol 22B, 5-8 (1983)