Methanol → 1-Tetralone

Participants

Reaction Conditions

Reaction Steps

A suspension of 7-nitro-1-tetralone (10.14 g, 0.053 mol) in MeOH (600 ml) was cooled to 0° C. and treated with NaBH4 (4.25 g, 0.11 mol. 2.1 equiv.). A nitrotetralone can be obtained by nitration of a 1-tetralone, the desired product being separated from minor component byproducts. The reaction mixture became homogeneous almost immediately. After stirring at 0° C. for 30 min. 2N HCl (100 ml) was added and stirring was continued for an additional 30 min. The reaction mixture was concentrated under reduced pressure (approx. 150 ml) and diluted with CH2Cl2 (200 ml) and H2O (100 ml). The aqueous layer was separated and extracted with additional CH2Cl2 (2×100 ml). The combined organic layers were washed with brine (100 ml), dried (Na2SO4), filtered and concentrated under reduced pressure to 7-nitro-1,2,3,4-tetrahydo-2-naphthalenol as a white solid (10.13 g, 99%) which was used in the next step without further purification. Rf (silica gel): 0.50 (40% hexane: 40% CH2Cl2: 20% EtOAc); 1H NMR (300 MHZ, CDCl3) 8.29 (d,J=2.1 Hz, 1H), 7.97(dd,J=2.1 and 8.1 Hz, 1H), 7.21 (d, J=8.1 Hz, 1H), 4.80-4.77 (m, 1H), 2.94-2.73 (m, 2H), 2.47 (d, J=6.0 Hz, 1H), 2.12-1.93 (m, 2H), 1.90-1.74 (m, 2H); 13C NMR (75 MHZ, CDCl3) 146.5, 145.1, 140.6, 129.9, 123.6, 122.2, 67.8, 31.9, 29.3, 18.6.

Provenance & Evidence