Catalyst-Free One-Pot Access to Pyrazoles and Disulfide-Tethered Pyrazoles via Deamidative Heteroannulation of beta-Ketodithioesters with Semicarbazide Hydrochloride in Water

Koley, Suvajit and Panja, Sumit Kumar and Soni, Sonam and Singh, Maya Shankar (2018) Catalyst-Free One-Pot Access to Pyrazoles and Disulfide-Tethered Pyrazoles via Deamidative Heteroannulation of beta-Ketodithioesters with Semicarbazide Hydrochloride in Water. In: ADVANCED SYNTHESIS & CATALYSIS, 360 (9). pp. 1780-1785.

PDF Adv_Syn_Cat_360-9_1780_2018.pdf - Published Version Restricted to Registered users only Download (1MB) | Request a copy

Abstract

An operationally simple, mild, and catalyst-free one-pot protocol to access privileged pyrazoles and disulfide-tethered pyrazoles has been devised by 3+2] heteroannulation of beta-ketodithioesters with semicarbazide hydrochloride in water under open air. The pH of the medium played a key role toward the selectivity switch, as refluxing in water led to the formation of pyrazoles, whereas addition of sodium acetate in water enabled the formation of disulfide-tethered pyrazoles. Notably, this protocol involves a tandem sequence of amination/cyclization/dehydration/hydrodesufurization/hydrolysis/deamida tive reactions. A mechanistic rationale for this regio-/chemoselective domino reaction is outlined, which is well supported and validated by density functional theory calculations.

Item Type:	Journal Article
Publication:	ADVANCED SYNTHESIS & CATALYSIS
Publisher:	WILEY-V C H VERLAG GMBH, POSTFACH 101161, 69451 WEINHEIM, GERMANY
Additional Information:	Copy right for this article belong to WILEY-V C H VERLAG GMBH, POSTFACH 101161, 69451 WEINHEIM, GERMANY
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	23 May 2018 14:55
Last Modified:	23 May 2018 14:55
URI:	http://eprints.iisc.ac.in/id/eprint/59916

Actions (login required)

View Item