Po/yhedron Vol. 12, No. 20, pp. 2447-2451, 1993 Printed in Great Britain 0277-5387/g) $6.00 + .oO 0 1993 Pergamon Press Ltd zyxwvutsr SYNTHESIS AND CHARACTERIZATION OF ALKYL-2,2,2-TRIFLUOROETHYL SULPI-IITES SURAJ P. NARULA,” SUKHJEEVAN KAUR, RAVI SHANKAR and SURINDER K. SHARMA Department of Chemistry, Panjab University, Chandigarh-160014, India zyxwvutsrqponmlkjih (Received 2 June 1993 ; accepted 7 July 1993) Abstract-Some new asymmetric organic sulphites, R’CH20S(0)OCH2CF3 (R’ = H, CH,, CH,Cl, C2H, or C3H7) were prepared and characterized by elemental analyses, IR, mass and multinuclear (‘H, ’ 3C, “F) NMR spectral studies. The quantitative increase of ‘H NMR chemical shift difference of non-equivalent protons with bulk of the R’ substituent is reported. Organic sulphites have such practical uses as: (i) insecticides ; ’ (“) 11 non-aqueous solvents2 and (iii) polymerization catalysts.’ These compounds have also been investigated for reasons of their chemical reactivity&* and structural features.4”g-’ 3 The struc- ture of these compounds has been studied from the standpoint of non-equivalence of cc-methylene protons located in the vicinity of oxygen atoms, linked to the asymmetric centre C--n. In these studies attention has mainly been focussed on the structure of cyclic sulphites while only a few acyclic organic sulphites are characterized;‘W’2 and even amongst them very little is known about the nature of asymmetrical sulphites, ROS(O)OR’. Therefore, alkyl-2,2,2_trifluoroethyl sulphites R’CH20S(0) OCH2CF3 (R’ = H, CH,, CH,Cl, C2H5, C3H7) are isolated, characterized by molecular spectro- scopy and the results obtained are reported in this paper. EXPERIMENTAL All reactions were performed under dry nitrogen. Thionyl chloride (Fluka) was distilled over mercury before use. Methyl/ethyl/n-propyl/n-butyl alcohols were dried by standard methods given in the litera- ture. I4 2-Chloroethy1/2,2,2-trifluoroethyl alcohols (Fluka) were used as such. Sulphur and chlorine were estimated by gravimetric methods. I5 * Author to whom correspondence should be addressed. Elemental analyses of the samples were obtained using a Perkin-Elmer (Model 2400) CHN Analyser. Gas Chromatographic analyses were performed on a Perkin-Elmer (Sigma 300) instrument using 6m x l/S” long SE-52 column and helium as carrier gas with recorder rate 0.5 cm min- ‘. IR spectra were recorded as thin films using KBr optics on a Perkin-Elmer 1430 ratio recording spec- trophotometer. ‘H and “C NMR spectra were obtained on Briiker AMX400 instrument using TMS as internal standard; while “F NMR spectra were recorded on Varian EM-390 with Freon-l 1 as external reference. Mass spectra were recorded at 70 eV on VG-Analytical70-S Spectrometer. Preparative methods Methyl/ethyl/2-chloroethyl/n-propyl/n-butyl chlo- rosulphites were prepared by the reaction of thionyl chloride (40.0 mmol) and the corresponding alcohol (40.0 mmol) as reported earlier.4 The purity of these compounds was checked by elemental analyses, IR and ‘H NMR spectral data. Preparation of methyl/ethyl/2-chloroethyl/n-pro- pylln-butyl-2,2,2-triJZuoroethy1 sulphite A slow addition of 2,2,2-trifluoroethanol (13.7 mmol) was carried out separately into methyl/ ethyl/2-chloroethyl/n-propyl or n-butyl chlorosul- phite (13.7 mmol) at 50-6O”C with constant stirring. A slow stream of dry nitrogen was bubbled into the reaction mixture to expel the HCl gas 2447