Strained heterocyclic systems. 11. Crystal and molecular structure of 1,2-dihydrocyclobuta[b]quinoline

The structure of the title compound (1) has been elucidated by an X-ray crystal determination. The crystals are triclinic, space group PI with a unit cell of dimensions a = 6.6109(5), b = 7.5939(4), c = 9.3171(6), α = 77.133(5), β = 75.566(6), γ = 63.575(5). The model was refined to an R value (unweighted) of 4.3% for 1551 independent reflections. The distortion of the heterocyclic ring, with a CNC bond angle of 112.5,° is in accordance with a prior calculation and relates to the observed reduction in basicity.