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Synthetic and natural C18furanoid fatty esters were successfully converted to the corresponding furanoid alcohols, aldehydes, halides, ethers, acetates, mesylates, and chain extended by two carbon atoms in high yield to the corresponding C20furanoid ester homologues. Acid hydrolysis of the furanoid esters furnished dioxostearate derivatives, which were cyclized with ammonium carbonate or ammonia in titanium chloride and with phosphorus pentasulfide to pyrrole and thiophene ester derivatives, respectively.

Abstract: Synthetic and natural C18 furanoid fatty esters were successfully converted to the corresponding furanoid alcohols, aldehydes, halides, ethers, acetates, mesylates, and chain extended by two carbon atoms in high yield to the corresponding C20 furanoid ester homologues. Acid hydrolysis of the furanoid esters furnished dioxostearate derivatives, which were cyclized with ammonium carbonate or ammonia in titanium chloride and with phosphorus pentasulfide to pyrrole and thiophene ester derivatives, respectively.

The fatty acid composition ofBiota orientalisseed oil consists of palmitic (5.1%), stearic (3.4%), oleic (15.3%), linoleic (25.6%), linolenic (34.7%), C20:3(11c,14c,17c) 4.9%, and C20:4(5c,11c,14c,17c) 10.5%. The unsaturated fatty esters derived fromBiotaoil were epoxidized and subsequently treated with NaI-PrI-DMSO. Chromatographic separation of the complex product mixture revealed the presence of C18-oxo, C18-furanoid, and C18-and C20-oxo-furanoid esters. Epoxidation of a pure sample of C20:4(5c,11c,14c,17c) followed by NaI-PrI-DMSO treatment gave a mixture of C20-dioxo-furanoid esters. The positions of the oxo and furanoid groups in the various derivatives were determined by GC/MS analysis.

Reaction of a C18furanoic fatty acid with dimethyl dicarboxylate (DMAD) furnished the corresponding bicyclo Diels-Alder adduct, which was partially hydrogenated over Pd/BaSO4. Heat treatment (160–180°C) of the partially hydrogenated product caused a retro-Diels-Alder reaction to yield a furanoid fatty acid derivative containing methoxycarbonyl (COOCH3) substituents at the 3-and 4-positions of the furan nucleus. Reduction of the COOCH3substituents with LiBH4gave the corresponding CH2OH-substituted furanoid fatty acid. Hydrogenation of the latter over Pd/C furnished the desired dimethyl-substituted furanoid acid derivative (overall yield 60%). The spectroscopic properties of the intermediates and product are reported.

Dimethylene interrupted dioxo derivatives of 10, 13-epoxy-11-methylocadeca-10, 12-dienoate (from latex) and 9 (10), 12 (13)-epoxyoctadeca-9 (10), 11 (12)-dienoates (from linoleate) were successfully methylated at the methylene carbons located between the two oxo groups using methyl iodide and KOH in DMSO. The resulting dimethyldioxo derivatives were cyclodehydrated to furnish methyl 10, 13-epoxy-11, 12-dimethyloctadeca-10, 12-dienoate and a mixture of methyl 9(10), 12(13)-epoxy-10(11), 11(12)-dimethyl-octadeca-9(10), 11(12)-dienoate. Similarly, methylation at C-11 of methyl 12-oxo-octadec-as-9-enoate (from methyl ricinoleate) gave methyl 9, 12-epoxy, 11-methyloctadeca-9, 11-dienoate on cyclodehydration.

Abstract: Dimethylene interrupted dioxo derivatives of 10, 13-epoxy-11-methylocadeca-10, 12-dienoate (from latex) and 9 (10), 12 (13)-epoxyoctadeca-9 (10), 11 (12)-dienoates (from linoleate) were successfully methylated at the methylene carbons located between the two oxo groups using methyl iodide and KOH in DMSO. The resulting dimethyldioxo derivatives were cyclodehydrated to furnish methyl 10, 13-epoxy-11, 12-dimethyloctadeca-10, 12-dienoate and a mixture of methyl 9(10), 12(13)-epoxy-10(11), 11(12)-dimethyl-octadeca-9(10), 11(12)-dienoate. Similarly, methylation at C-11 of methyl 12-oxo-octadec-as-9-enoate (from methyl ricinoleate) gave methyl 9, 12-epoxy, 11-methyloctadeca-9, 11-dienoate on cyclodehydration.

Abstract: Reaction of a C18 furanoic fatty acid with dimethyl dicarboxylate (DMAD) furnished the corresponding bicyclo Diels-Alder adduct, which was partially hydrogenated over Pd/BaSO4. Heat treatment (160–180C) of the partially hydrogenated product caused a retro-Diels-Alder reaction to yield a furanoid fatty acid derivative containing methoxycarbonyl (COOCH3) substituents at the 3-and 4-positions of the furan nucleus. Reduction of the COOCH3 substituents with LiBH4 gave the corresponding CH2OH-substituted furanoid fatty acid. Hydrogenation of the latter over Pd/C furnished the desired dimethyl-substituted furanoid acid derivative (overall yield 60%). The spectroscopic properties of the intermediates and product are reported.

A rapid method for the synthesis of methyl 9,12-epoxyoctadeca-9,11-dienoate from methyl ricinoleate was developed. Methyl ricinoleate was oxidized to the corresponding keto ester, which was treated with mercury (II) acetate to give the required furanoid ester. Dry column silica gel chromatography was used for the purification process and was found to be reliable and efficient.

Abstract: A rapid method for the synthesis of methyl 9,12-epoxyoctadeca-9,11-dienoate from methyl ricinoleate was developed. Methyl ricinoleate was oxidized to the corresponding keto ester, which was treated with mercury (II) acetate to give the required furanoid ester. Dry column silica gel chromatography was used for the purification process and was found to be reliable and efficient.