3-(N-propionyl-N-n-propylamino)chroman → 8-Chloro-7-nitro-2-(n-propylbenzoyl)amino-1,2,3,4-tetrahydronaphthalene

Participants

Reaction Steps

Fuming nitric acid (100 ml), 33% in concentrated sulphuric acid was added dropwise to a solution of 72 g (0.22 mol) 8-chloro-2-(n-propylbenzoyl)amino-1,2,3,4-tetrahydronaphthalene in 300 ml nitromethane at 0° C. The mixture was allowed to reach ambient temperature and was stirred over night. After pouring on ice water/diethyl ether the mixture was basified (sodium carbonate solution) and the phases separated. The organic phase was dried (magnesium sulphate), filtered and evaporated to a residue of 65.5 g of an isomeric mixture. Elution of the mixture on a silica column (isooctane/diethyl ether, 1:1) gave 19 g of 8-chloro-5-nitro-2-(n-propylbenzoyl)amino-1,2,3,4-tetrahydronaphthalene and 12 g of the desired isomer; 8-chloro-7-nitro-2-(n-propylbenzoyl)-amino-1,2,3,4-tetrahydronaphthalene. MS m/e 372 (M+, 3), 374 (M+ +2, isotope, 1), 105 (100), 164 (72), 77 (35), 134 (16), 165 (9).

Provenance & Evidence