@article { ISI:000261163000013, title = {Structural elucidation of propargylated products of 3-substituted-1,2,4-triazole-5-thiols by NMR techniques}, journal = {Magnetic Resonance in Chemistry}, volume = {46}, number = {12}, year = {2008}, month = {DEC}, pages = {1168-1174}, publisher = {JOHN WILEY \& SONS LTD}, address = {THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND}, abstract = {

Propargylation of 3-substituted-1,2,4-triazole-5-thiols, which predominantly exist as their thione tautomers, was carried out with the view to synthesize different heterocycles and study their biological activity. Three different products namely, a mono S-propargyl and two S,N-dipropargyl regioisomers, arising from N1/N2 substitution, were isolated and characterized. Unambiguous structural elucidation of the regioisomers of S,N-dipropargyl derivatives was achieved by means of (13)C-(1)H HMBC technique. The proportion of the regioisomers was found to vary with the substituent on the 1,2,4-triazole thiols. No product corresponding to N4 substitution was isolated from any of the reactions carried out. Copyright (C) 2008 John Wiley \& Sons, Ltd.

}, keywords = {(1)H NMR, (13)C NMR, (15)N NMR, 1, 2, 4-triazoles, HMBC, NMR, Regioisomers}, issn = {0749-1581}, doi = {10.1002/mrc.2307}, author = {Chaudhary, Preeti M. and Chavan, Sayalee R. and Kavitha, M. and Maybhate, Shailaja P. and Deshpande, Sunita R. and Likhite, Anjali P. and Rajamohanan, P. R.} } @article { ISI:000326674800001, title = {GIAO/DFT studies on 1,2,4-triazole-5-thiones and their propargyl derivatives}, journal = {Magnetic Resonance in Chemistry}, volume = {51}, number = {12}, year = {2013}, month = {DEC}, pages = {767-774}, publisher = {WILEY-BLACKWELL}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {

Density functional theory (DFT)/Becke-Lee-Yang-Parr (B3LYP) and gauge-including atomic orbital (GIAO) calculations were performed on a number of 1,2,4-triazole derivatives, and the optimized structural parameters were employed to ascertain the nature of their predominant tautomers. C-13 and N-15 NMR chemical shifts of 3-substituted 1,2,4-triazole-5-thiones and their propargylated derivatives were calculated via GIAO/DFT approach at the B3LYP level of theory with geometry optimization using a 6-311++G** basis set. A good agreement between theoretical and experimental C-13 and N-15 NMR chemical shifts could be found for the systems investigated. The data generated were useful in predicting N-15 chemical shifts of all the nitrogen atoms of the triazole ring, some of which could not be obtained in solution state N-15 HMBC/HSQC NMR measurements. The energy profile computed for the dipropargylated derivatives was found to follow the product distribution profile of regioisomers formed during propargylation of 1,2,4-triazole thiones. Copyright (c) 2013 John Wiley \& Sons, Ltd.

}, keywords = {1, 2, 4-triazole-5-thiones, C-13, DFT, GIAO, N-15, NMR, Regioisomers, tautomers}, issn = {0749-1581}, doi = {10.1002/mrc.4012}, author = {Phalgune, Usha D. and Vanka, Kumar and Rajamohanan, P. R.} } @article { ISI:000339128700053, title = {Highly regioselective C4-hydrazinylation of 2,4-dichloroquinolines: expedient synthesis of aminoquinoline substituted pyrrolidin-2,5-diones via hydrazinylquinolines}, journal = {Tetrahedron Letters}, volume = {55}, number = {30}, year = {2014}, month = {JUL}, pages = {4240-4244}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A new class of hydrazinylquinoline regio-isomers has been synthesized through SNAr reaction of 2,4-dichloroquinolines with hydrazine hydrate. The reaction stops at the mono-substitution product with high regioselectivity at the C-4 rather than C-2 position of dichloroquinolines. The hydrazinylquinolines were subsequently converted into aminoquinoline substituted pyrrolidin-2,5-diones in the presence of Eaton{\textquoteright}s reagent. (C) 2014 Elsevier Ltd. All rights reserved.

}, keywords = {5-diones, Eaton{\textquoteright}s reagent, Hydrazinylquinolines, Pyrrolidin-2, Regioisomers, SNAr reaction}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2014.05.132}, author = {Kumar, Gopal Senthil and Zeller, Matthias and Gonnade, Rajesh Ghanshyam and Prasad, Kamam Jayarampillai Rajendra} }