Structure of 3,5-dihydrobenz[f]indolizin-3-one

Abstract

Abstract. C12H9NO, Mr = 183.2, triclinic, P1, a = 8.837 (6), b = 7-910 (6), c = 6.903 (5) A, a = 108.2 (1), /3 = 77.7 (1), y= 101"4 (1) °, V= 443"4 A 3, Z = 2, Dx = 1"372 g cm -3, Mo Kce, A = 0.71069 ,£,,/z = 0-5 cm-1, F(000) = 192, T= 293 (2) K, R = 0.054 for 1626 reflections with I___3tr(/). Elemental analysis and the mass spectrum of the compound, and one-and two-dimensionally correlated NMR spectra are in good agreement with the results of the structure analysis, in which the molecule is found to be roughly planar.Experimental. As described in the literature (Rigo & Kolocouris, 1984), fine powder of (1) (lg, 4.97 mmol) was quickly added to hot (413 K), stirred polyphosphoric acid (20 g). The mixture was vigorously stirred for 1 h. The hot mixture was decanted over crushed ice (150 ml) and the aqueous solution was extracted with dichloromethane. The organic phase was washed with water, dried over K2CO3, * To whom correspondence should be addressed.0108-2701/91/040888-03503.00 filtered and concentrated to give 70% yield of a red powder, which was then treated overnight in dichloromethane at room temperature, with activated carbon, filtered and concentrated in part; pure yellow crystals of (4), which turned red in air, were obtained by slow evaporation of the solvent at 437 K.