S. N. Suryawanshi

The Reaction of Acyloxysulfonium Salt with Cyclic Enol Ethers: Novel Synthesis of Vinyl Sulfides

Abstract The reaction of 2,3-dihydrofuran (1), dihydropyran (2) and indole (8) with acyloxysulfonium salt (3) and Methyl amine furnished vinyl sulfides 6, 7 and 10 respectively in very good yields.

Diels-Alder reaction of in-situ generated 2-methoxycarbonyl-p-quinone with D-glucose based dienes: a new approach to forskolin

Abstract Diels-Alder reaction of 2-methoxycarbonyl- p -quinone 3 with D -glucose based dienes 4 ( a – h ) furnished cis -adducts 10 ( a – h ) in a stereo- and regiospecific manner. Chemical transformation of 10 afforded 11 – 15 . Compounds 12 , 13 and 15 are key intermediates in the proposed synthesis of forskolin.

Mild and Efficient Conversion of Allylic Alcohols to Xanthates

Abstract The reaction of allylic alcohols (4–7) with sodium hydroxide, carbon disulfide and methyl iodide followed by heteroclaisen rearrangement over neutral alumina furnished (18–21) in 70–90% isolated yield.

Studies on Allylic Oxidation Reactions of Methyl Abietate

Abstract Allylic oxidation reactions of methyl abietate (2) with selenium dioxide and lead tetraacetate have been studied in different solvents. Oxidation of methyl abietate (2) with selenium dioxide in acetic anhydride furnished methyl 7α-O-acetyl dehydroabietate (5b) in 68 % yield.

Dual participation of in situ generated-p-benzoquinones with substituted furanoid vinyl glycals in cycloaddition reaction

Abstract In - situ generated 2-substituted- p -benzoquinones from 3 ( b – d ) showed dual reactivity towards substituted glucofuranodienes 1 ( a – c ) and 2 ( a – c ). The cycloaddition showed complete stereo- and regiochemical control.

FAST-ATOM BOMBARDMENT MASS SPECTRA OF ISOPROPYLIDENE DERIVATIVES OF GLUCOSE AND MANNOSE

Abundant [M + H]+, [M-H]+ and [M-CH3]+ ions are observed in the fast-atom bombardment mass spectra of isopropylidene derivatives of glucose and mannose. Formation of abundant [M-H]+ is attributed to beam-induced processes. The collision-induced dissociation spectra of the [M + H]+ ions of the α- and β- anomers of the glucose derivatives differ in the abundances of the fragment ions. As expected, marked differences are noticed in the fragmentations of the [M + H]+ and the corresponding [M + Li]+ ions. Lithium cationization induces cleavage of the isopropylidene ring. Copyright

AN EFFICIENT SYNTHESIS OF FUNCTIONALISED DECALIN VIA CYCLOADDITION REACTION OF D-GLUCOSE BASED DIENES AND 2-METHOXYCARBONYL-P-BENZOQUINONE

The cycloaddition reaction of D-glucose based dienes 1 (b,c) with in-situ generated 2-methoxycarbonyl-p-benzoquinone 2 furnished cycloadducts 3 (a, b) with excellent stereo-and regiochemical control. The cyclo-adduct 3b on further transformations furnished fuctionalised decalin 7c in quantitative yield.

Diels-Alder reaction of in-situ generated p-benzoquinones with isoprenoidal dienol acetate: Novel synthesis of 2-isoprenoidal naphthalene-5, 8-quinols☆

Diels-Alder reaction of citral dienol acetate 3 with in-situ generated p-benzoquinones from 4 (a-d) furnished cycloadducts 5 (a-d) in quantitative yields. Brief exposure of 5b towards activated silica gel furnished acyl migrated product 6a in quantitative yield.

Phase Transfer Catalyzed Alkylation: An Efficient Protection of Acid Labile Hemiketals

Abstract The reaction of hemiketals (1–6) with sodium hydroxide and methyl iodide in the presence of TBAI as a catalyst furnished methoxy hemiketals (7–10) in more than 90% yield.

Novel Synthesis of Polyhydroxy Pyrrolidines

Abstract The reductive elimination-amination of 2(a, b) in the presence of amines 3 (a, b) under ultrasound irradiation provides pyrrolidines 5 (a,b,g,h) in excellent yield.