Pseudohalogenation of methyl 9-hydroxy-cis-12-octadecenoate (I) and methyl 12-hydroxy-cis-9-octadecenoate (II) has been carried out with N, N-dibromobenzenesulfonamide (NNDBS). Compounds I and II, on reaction with NNDBS, formed four and three products, respectively. The interesting feature of these reactions was the formation of 1,4-epoxy compounds. The structures of individual compounds were established with the help of elemental and spectral analysis. JAOCS 74, 713-717 (1997). KEY WORDS: 1,4-Epoxy fatty esters, methyl isoricinoleate, methyl ricinoleate, NNDBS.Advances in modification of fatty chemicals have recently been made in various directions. Much research attention is being directed toward the addition of a group of reagents, categorized as "pseudohalogens," to the double bonds of aliphatic and alicyclic compounds. A number of pseudohalogens have come into prominence (1-6), viz., iodine isocyanate, N,N-dichlorourethane, monochlorourethane, chlorine azide, bromine azide, iodine azide, nitrosyl chloride, nitryl iodide, N,N-dibromoacetamide, N,N-dibromobenzene sulfonamide (NNDBS), etc.Addition of pseudohalogens to an unsaturated system is important (7-9) and has been known for a long time to prepare a variety of derivatives. Foglia et al. (10) have investigated the addition of NNDBS to internal olefins. The major products were isomeric mixtures of β-bromosulfonamides, while dibromide and bromohydrins were found in small amounts. Ahmad et al. (9), Foglia et al. (10), and Nasirullah et al. (11) reported the reaction of NNDBS with 10-undecenoic, oleic, and trans-2-hexadecenoic acids. In continuation of our program to derivatize fatty acids for possible industrial utilization, we report here the reaction of NNDBS with methyl 9-hydroxy-cis-12-octadecenoate (methyl isoricinoleate, I) and methyl 12-hydroxy-cis-9-octadecenoate (methyl ricinoleate, II).These reactions were performed to investigate the effect of neighboring group participation of the hydroxyl function at the β-and γ-positions relative to the unsaturation. The results of the reactions are interesting because we have been able to isolate and characterize 1,4-epoxy compounds besides other expected products.
EXPERIMENTAL PROCEDURESInfrared (IR) spectra were obtained with a Perkin-Elmer 621 spectrophotometer (Norwalk, CT) (liquid film or 1% solution in carbon tetrachloride). Nuclear magnetic resonance (NMR) spectra were recorded in CCl 4 with a Varian A60-NMR spectrometer (Palo Alto, CA) and tetramethyl silane as internal standard. Chemical shifts were measured in ppm downfield from the internal standard (δ = 0). The abbreviations "s, d, m, br, t" denote singlet, doublet, multiplet, broad, and triplet, respectively. Mass spectra (MS) were measured with a JEOL JMS-D300 spectrometer (Tokyo, Japan). Thin-layer chromatography (TLC) plates were coated with silica gel G (0.25 mm thickness), and a mixture of petroleum ether/diethyl ether/acetic acid (70:30:1, vol/vol/vol) was used as developing solvent. The spots were visualized by charring at 100°C after spr...