Synthesis and Crystal Structure of Tetraethyl syn-1,5,8,8bβ-Tetrahydrocyclobuta[1,2-b:3,4-b′]dipydine-3,4aβ,7,8aβ(4H,4bβH)-tetracarboxylate

摘要

The synthesis of syn-photodimer from 1,4-dihydropyridine without 4-aryl was studied, and its single crystal was obtained (C_(22)H_(30)N_2O_8, M_r = 450.48). It crystallizes in monoclinic, space group P2_1/c with a = 11.937(2), b = 20.913(4), c = 9.763(2) A, β = 108.46(3)°, V = 2311.9(8) A~3, Z = 4, D_c = 1.294 g/cm~3, F(000) = 960, μ = 0.099 mm~(-1), R = 0.0640 and wR = 0.1464 for 4077 unique reflections with 1598 observed ones (Ⅰ > 2σ(Ⅰ)). It is shown that the whole molecular structure of the title compound is a twist-boat conformation, and the two double bonds have a trend of potential intramolecular reaction under high-energy irradiation.