M. S. Ahmad

Cyclopropenoid fatty acids in seed oils ofSida acuta andSida rhombifolia (malvaceae)

Seed oils ofSida acuta andSida rhombifolia were found to contain sterculic (11.0, 10.8%) and malvalic (1.7, 2.0%) acids respectively, in addition to the normal fatty acids. Co-occurrence of these acids was established by gas liquid chromatography of the silver nitrate-methanol-treated methyl esters usingSterculia foetida esters as a reference standard. This gas liquid chromatography technique of quantitation was found most suitable to estimate these acids in low level cyclopropenoid acid-containing seed oils.

Eriolaena hookeriana seed oil: A rich source of malvalic acid

Abstract The seed oil of Eriolaena hookeriana (Sterculiaceae) contains malvalic (25.8%) and sterculic (6.0%) acids in addition to normal fatty acids. Eriolaena hookeriana is the second known species of the Sterculiaceae plant family whose seed oil contains more malvalic acid than sterculic acid. Gas chromatography-mass spectrometry (GS-MS) study of the silver nitrate-methanol treated methyl esters has been carried out for unequivocal characterisation of the individual cyclopropene acids. Genesis of diagnostic fragment ions is discussed.

Synthesis of sulfur heterocycles from α,β-unsaturated carbonyl fatty acid esters

Alkyl chain substituted oxathiolanes from allylic oxo are described. Reaction of methyl 4-oxo-trans-2-hexadecenoate (1) with β-mercaptoethanol yields methyl 4-oxathiolane-trans-2-hexadecenoate (II), methyl 4-oxathiolane-2(3)-(S-β-mercaptoethyl acetate) hexadecanoate (III) and methyl 4-oxathiolane-2(3)-(S-β-mercaptoethanol)hexadecanoate (IV).

Synthesis of tetrazole from α,β-unsaturated carbonyl fatty acid

Methyl 4-oxo-trans-2-octadecenoate (II), when treated with excess hydrazoic acid in the presence of BF3-etherate, produced 66% methyl 5-aza-nonadec-trans-2-enoate (4,5-d)-tetrazole (III), 10% methyl 5-aza-nonadec-4-oxo-trans-2-enoate (IV) and 7% pentadecamide (V). Individual products were characterized by spectral and elemental methods.

A novel oxo fatty acid in Plantago ovata seed oil

Abstract Plantago ovata seed oil contains two oxygenated fatty acids one of which is the known 9-hydroxyoctadec- cis -12-enoic acid. The other is 9-oxoact

Simmons-Smith reaction of allylic hydroxylated long chain α, β-unsaturated esters

The reaction of methyl 4-hydroxy-trans-2-hexadecenoate [1b] with diiodomethane in the presence of zinc-copper couple yielded methyl 4-methoxy-trans-2,3-methylenehexadecanoate [2] in a 70% yield, together with methyl 4-hydroxy-trans-2,3-methylenehexadecanoate [3] (∼20%). The presence of an allylic hydroxyl group in the α,β-unsaturated ester increases the yield of the cyclopropanation product. The formation ofo-methyl ether reveals the dual role of cyclopropanation and etherification by S.S. reagent of a hydroxylated olefinic compound.

Synthesis of N-[3-(p-aminophenyl)-1-carboxypropyl] derivatives of 1,4,7-triazacyclononane-N,N′-diacetic acid and 1,4,7,10-tetraazacyclododecane-N,N′,N″-triacetic acid: macrocyclic bifunctional chelating agents useful for antibodies labelling

Abstract Reactions of dicarboxymethylated triazacyclononane ( 6 ) and tricarboxymethylated tetraazyclododecane ( 7 ) with ethyl 2-(trifluorosulfonyloxy)-4-phenylbutanoate ( 3 ) afforded corresponding N-functionialised cyclic ester derivatives ( 8 ) and ( 12 ) which served as precursors of above titled macrocyclic bifunctional chelating agents.

Iodoazide addition to olefinic esters and their reaction with methanolic KOH

Addition of iodine azide to methyl 10-undecenoate (1), methyl oleate/elaidate (III,IV) and methyltrans-2-hexadecenoate (VII) yielded methyl 10-azido-11-iodoundecanoate (II, ∼ 100%), methylerythro/threo-9(10)-azido-10(9)-iodooctadecanoate (V,VI) and methylerythro-3-azido-2-iodohexadecanoate (VIII), respectively. The reaction of iodoazide adduct (II) with methanolic KOH yielded 10-azidoundec-10-enic acid (IX) and 10-oxoundecanic acid (X), while V and VI gave a mixture of 9(10)-oxooctadecanoic acid (XI). Adduct VIII, under the identical condition after esterification, gave 3 products, methyl 4-methoxy-trans-2-hexadecenoate (XII), 2-oxopentadecane (XIII) and methyl 3-methoxyhexadecanoate (XIV). The unusual behavior of VIII can be tentatively attributed to the role of adjacent carbonyl on the expected elimination of HI by methanolic alkali.

9-Hydroxydodecanoic acid, an acid from Blepharis sindica seed oil

Abstract A hitherto unknown hydroxy acid has been isolated from Blepharis sindica seed oil has been characterized as 9-hydroxydodecanoic acid by IR, NMR and mass spectral studies. The structure of this acid was further supported by its chemical transformations.

Cyclopropenoid fatty acids in seed oils ofurena repanda andthespesia lampas

Seed oils ofUrena repanda andThespesia lampas (Malvaceae) were found to contain malvalic (2.6, 0.6%) and sterculic (1.1, 2.1%) acids, respectively, besides the normal fatty acids. Cooccurrence of these two acids were established by gas Chromatographic analysis of silver nitrate/methanol-treated methyl esters usingSterculia foetida esters as a reference standard.