S. Swaminathan
University of Madras
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Featured researches published by S. Swaminathan.
Tetrahedron Letters | 2001
D Rajagopal; R Narayanan; S. Swaminathan
Abstract One-pot syntheses of ketol SS - 5a , enone S - 2 and optically active spiroenediones S - 14 , R - 7 and S - 15 are reported.
Tetrahedron | 1982
C.Seshu Sekhara Rao; G. Kumar; K. Rajagopalan; S. Swaminathan
Abstract The spirovinyl carbinol 5 when treated with methanolic potassium hydroxide was found to rearrange to perhydrophenalene- 1,4-dione 6 via an anionic oxy-Cope rearrangement followed by an intramolecular Michael addition. The epimeric mixture of ketol acetates 15a and 15b was also found to rearrange to 2-hydroxy-2-methyl perhydroacenaphthylene-1,3-dione 16 on treatment with base.
Tetrahedron Letters | 1982
P. Geetha; C.A.M.A. Huq; K. Rajagopalan; S. Swaminathan
The divinyl carbinols 3 and 6 furnished the benzotropones 4 and 7 respectively, when treated with base.
Tetrahedron Letters | 1980
N. Raju; K. Rajagopalan; S. Swaminathan; J.N. Shoolery
Abstract The carbinol 8 is found to rearrange to the bicyclo (2,2,2) octane derivative 10 in the presence of base; the rearrangement involves a transannular reaction in a ten membered ring resulting from an Oxy-Cope system.
Tetrahedron Letters | 1984
R. Uma; S. Swaminathan; K. Rajagopalan
The synthesis and rearrangement of the optically active etynyl and vinyl carbinols 3 and 4 are reported. The rearrangements are found to be concerted when carried out with KH-THF and non-concerted with KOH-methanol.
Tetrahedron | 1969
S. Swaminathan; Kannupal Srinivasan; P.S. Venkataramani
The hydroxy enones 5a, 5b, 5c, 4d, 4a and 4b rearrange when treated with aqueous alkali to the diones 6a, 6b, 8 and 13 and acids 9 and 12 respectively. The diones 2 and 6a are also formed by thermal rearrangement of enones 1a and 5a.
Tetrahedron | 1966
R. Selvarajan; Joseph P. John; K.V. Narayanan; S. Swaminathan
Abstract Michael addition of methylvinyl ketone to 2-methylcycloheptane-1,3-dione (II) obtained by methylation of cycloheptane-1,3-dione furnishes 2-methyl-2(3′-oxobutyl) cycloheptane-1,3-dione (III) which is cyclized and dehydrated in a single step to afford the title compound (Ic) in the presence of a mixture of pyrrolidine and acetic acid. A by-product isolated in this cyclization is the bridged ketol VII. Treatment of III with p -toluenesulphonic acid gives predominantly the acid IV and only low yields of Ic. The reaction of Ic with lithium acetylide furnishes an unexpected product formulated as IX. An explanation for the differing course of ethynylation of the analogous diones Ia, Ib and Ic is given.
Tetrahedron | 1990
G. Sathyamoorthi; K. Thangaraj; P. C. Srinivasan; S. Swaminathan
Abstract A general synthesis of trans bicyclic carbinols with an angular methyl substituent using the anionic oxy-Cope rearrangement is reported. The carbinols 13a , l3b , 14a , 14b and 15 furnish the bicyclic carbinols 16a , 16b 17a , 17b and 18 when treated with potassium hydride in 1,2-dimethoxyeth ane.
Tetrahedron | 1986
R. Uma; K. Rajagopalan; S. Swaminathan
The synthesis and rearrangements of the chiral carbinols 8 and 9 are described. With KH-THF. both the carbinola gave optically active rearrangement products; with alkali in methanol, they gave optically inactive rearrangement products. The results are interpreted as favouring a concerted mechanism for the hydride catalysed rearrangements and a non-concerted mechanism for the rearrangements catalysed by alkali in methanol.
Tetrahedron Letters | 1982
K. Thangaraj; P. C. Srinivasan; S. Swaminathan
The divinyl carbinols 3a and 3b furnished octalinols 4a and 4b respectively on treatment with base.