Syntheses and PMR Studies of 1,2,3,4,5-Pentachlorocyclohexane Isomers, Tetrachloromonomethoxycyclohexane Isomers and Related Compounds

Abstract

Two diastereomers of 1,2,3,4,5-pentachlorocyclohexane tt and two diastereomers of tetrachloromonomethoxycyclohexane were synthesized stepwise from diastereomers of 3 4 5-. ' , tnchlorocyclohexene, which had been derived from the DL-(36/45)-, DL-(34/56)-and (346/5)-isomers of 3,4,5,6-tetrachlorocyclohexene tt (a-, f3-and y-BTC, respectively) by selective reduction with LiAlH4. The configurations of all the products and intermediary trichlorocyc10hexene isomers were determined by PMR studies.During structure-activity relationship studies on BHC isomers and analogs, compounds having a hydrogen atom in place of a chlorine atom in the structure of ),-BHC (lindane) (I) are required. We here describe the synthesis of two such diastereomers of pentachlorocyclohexane: the 134/25-isomer (lI)tt having an intermediary structure of u-(III) and y-BHC, and the 1245/3-isomer (IV) with that of ()-(V) and y-BHC. We also describe the preparation of two diastereomers (VI and VII) of tetrachloromonomethoxycyclohexane with the configuration 134/25. The configurations of these compounds were determined by synthetic routes, and by PMR spectroscopic analyses. We also report the preparation of three new diastereomers of 3,4,5-trichlorocyclohexene as the key intermediates in the synthetic course to the pentachlorocyclohexanes or tetrachloromonomethoxycyclohexanes starting from three isomers of BTC (VIII, IX t Studies on BHC Isomers and Related Compounds. Part XI.tt The nomenclature and numbering system adopted in this report follow that described in a previous report. lI The following abbreviations are used: BHC= 1,2,3,4,5,6-hexachlorocycIohexane, BTC = 3,4,-5,6-tetrachlorocyclohexene, PMR=proton magnetic resonance spectroscopy, IR=infrared absorption spectroscopy, tIc = thin-layer chromatography. and X). Synthetic methods 1. Three diastereomers of 3,4,5-trichlorocyclohexeneReactions between lithium aluminum hydride and the compound VIII, IX and X (u-, (3-and y-BTC, respectively) gave only the respective 34/5-(XI), 3/45-(XII) and 35/4-isomer (XIII). Although compound X might afford XIII also by an SN2 reaction, the entire results seem to be a proof that the SN2' mechanism prevails. Another possible reaction course (SN2 mechanism) should produce XII, XI and XI from VIII, IX and X, respectively, but we did not find any of these compounds in the products of the reactions (see Fig. 2).The reaction mechanism was studied using lithium aluminum deuteride instead of the hydride. The structures of the deuteriated products were examined by PMR. From the isomer VIII, only XI' and not XI" was obtained (Fig. 2). Compound XI' was shown to have the pseudo-axial deuterium atom at the 6-position. Similarly, IX and X gave XII' and XIII', respectively. Results showed that these deuteriated products were produced by an SN2' attack of lithium aluminum deuteride

Radiation- and photo-induced degradation of five isomers of 1,2,3,4,5,6-hexachlorocyclohexane.

“…5, we confirmed that the configuration of this isomer is la, 2a, 3/?, 4a, 5a and the conformation of chlorine atoms is le 2a 3a 4a 5e. This result is consistent with the conclusion reached by Tanaka et al 15) The forth compound (IV) whose relative retention time on OV-17 column was 0.88, showed mp75°C and M+254. From the NMRand MSspectra shown in Fig.…”

γ-BHC: Its history and mystery – why is only γ-BHC insecticidal?

“…These include hydrogen atom (H) [62,63], other non-Cl halogens [64][65][66], and various chemical groups, including alkoxy [58,63], alkylthio [67,68], and methyl [69] groups (see the synthetic routes in Fig. 7).…”

Syntheses and PMR Studies of Pentachlorocyclohexanecarbonitrile, Pentachloromethylcyclohexane and Tetrachlorodimethylcyclohexane

“…The PMR data for VIII (90 MHz, in CCI 4 ) cis-3,6-Dimethyl-l,4-cyclohexadiene (X) was obtained as a xylene solution from cis,cis-3,6-dimethylcyclohex-4-ene-cis-l,2-dicarboxylic acid (10.9 g) which had been prepared via the Diels-Alder condensation of trans, trans-2,4-hexadiene with maleic anhydride.I ol A solution of chlorine in CCl 4 was added dropwise under ice cooling to the stirred solution of X in xylene containing three drops of DMF until no more chlorine could be taken up. After additional stirring for 30 min at room temperature, the reaction mixture was extracted with chloroform and dried.…”