Tri-n-butylphosphine catalysis 3- 2-methyl-2-nitropropyl indole

A solution of gramine (87,3 mg, 0,50 mmol) and 2-nitropropane (33.7 mg, 0.38 mmol) in CHjCN (3 ml) was treated with -Bu3P (18.6 mg, 0.l4mmol). The mixture was refluxed for 4 h. The solvent was removed in vacuo and the residue was acidified with 0.5N aq. HCl and extracted with 95 5 CHjClj-MeOH. The extract was washed with brine and dried (Na2S04). The solvent was removed in vacuo and the residue purified by TLC to yield 138.5 mg (99% yield) of the product. 

A solution of gramine methosulfate (30.0 g, 0.10 mol) and NaCN (15,0 g, 0.30mol) in water (300 ml) was heated to 65-70°C for 1 h. A colourless oil separated as the reaction proceeded. The solution was cooled and saturated with Na2S04 and extracted with ether (400 ml). The ether was removed in vacuo and the residue purified by high vacuum distillation to give the product in 94% yield. 

Gomez-Monterrey. M. J. Dominquez, R. Gonzalez-Muniz, J. R. Harto and M. T, Garcia-Lopez, Tetrahedron Lett. 32, 1089 (1991). 

Hamamoto, K. Nakagawa, F. Yamada and T. Ohta, Heterocycles 37, 7l9 (1994). M. Nettekoyen, M. Psiorz and H, Waldmann, Tetrahedron Lett. 36, 1425 (1995). 

Nakamura and M. Nakagawa, Chem. Pharm. Bull. 23, 2990 (1975). 

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