Structure of a trichlorocyclohexenone from bleached kraft chlorination-stage effluent

Several compounds suspected to be mutagenic have been isolated by large scale fractionation of chlorination-stage effluent from a bleached kraft pulp mill. When reacted with diazomethane, one of these compounds yields a crystalline material, 1. Crystals of 1 are triclinic, a = 7.8814(7), b = 8.3988(8), c = 10.309(1) A, α = 71.529(8), β = 80.002(7), γ = 62.587(9)°, Z = 2, space group The structure was solved by Patterson and Fourier techniques and was refined by full-matrix least-squares procedures to R = 0.030 and Rw = 0.036 for 1795 reflections with I ≥ 3σ(I). The structure analysis has unambiguously identified compound 1 as 1,6-dioxa-4,4,10-trichlorodispiro[2.1.4.3]dodec-10-en-12-one, implying that the material originally present was 1-oxa-6,10,10-trichlorospiro[4.5]dec-6-en-8,9-dione.