Purification and Characterization of Lactobacillus bulgaricus Diaphorase

γ-Isomer of 1,2,3,4,5,6-hexachlorocyclohexane (BHC) showed greater decomposition on γ or UV irradiation of five isomers of BHC in crystalline state or in 2-propanol solution. The α- and δ-isomer of BHC and known la, 2a, 3e, 4e, 5e-pentachlorocyclohexane were separated from the irradiation product of crystalline γ-BHC. Four compounds were isolated from the irradiation product of γ-BHC in 2-propanol. Two compounds were tetrachloro-cyclohexenes (C₆H₆C1₄): γ-isomer (mp 86 ~87°C) and ?-isomer (mp 99 ~ 100°C). The other two were isomers of pentachlorocyclohexane (C₆H₇C1₅). One of them (mp 78 ~ 8.5°C) was consistent with known meso-1e,2a,3a,4a,5e isomer. The molecular structure of the other (mp 75°C) established by X-ray crystal structure analysis was 1α, 2α, 3α, 4β, 5α configuration or le 2a 3e 4e 5e conformation of CI atoms. A reaction mechanism was proposed that included a radical chain reaction and chlorine atom migration.