The title compound was prepared using a modified procedure (see below) to that described by H. J. Roth et al., Arch. Pharmaz., 1976, 309, 597. 2-Amino-1-benzyl-3-cyano-4,5,6,7-tetrahydroindole (D1) (1.255 g; 5 mM) was added to a solution of ethyl acetoacetate (0.655 g; 5 mM) in toluene (60 ml) containing para-toluenesulphonic acid (30 mg), and the mixture refluxed vigorously for 1 h with water separation (Dean and Stark apparatus). To the cooled solution was then added 1M sodium ethoxide in ethanol (6 ml) and the mixture refluxed for a further 2 h. The cooled solution was poured onto water, and the pH of the stirred mixture adjusted to 7 using 5M hydrochloric acid. The toluene layer was then separated, and the aqueous phase re-extracted with toluene. The combined organic phase was washed with brine, dried and evaporated to give a brown oil (1.5 g). Crystallisation from ethanol afforded the title compound as off-white needles (0.8 g; 44%), m.p. 145.5° -147°.
