N -Chlorosuccinimide (NCS)

Abstract

(A) Håkansson and co-workers have discovered the absolute asymmetric synthesis of 1-chloroindene in 87-89% ee and 78-97% yield utilizing NCS and a single crystal of novel diindenylzinc reagent [Zn(ind)2(pic)2].5 (Chemical Equation Presented) (B) The application of NCS and an organophosphine reagent for the synthesis of polychlorinated hydrocarbon motifs with multiple sp3 C-Cl bonds arranged in a regularly spaced pattern with proper stereochemical configuration has been developed by Tanaka and co-workers.6 (Chemical Equation Presented) (C) Nasim and Crooks have utilized the oxidative power of NCS for the convenient synthesis of pharmacologically important 1,2,4-thiadiazolidine-3,5-diones (TDZD) via an oxidative condensation of isothiocyanate and isocyanate.7 This method provides a safe and easy alternate method for the synthesis of thiadiazolidinones to the classical reagents like chlorine gas or SO2Cl2. (Chemical Equation Presented) (D) De Kimpe and co-workers have developed the chlorination of 1-alkyl-3,4-dihydroisoquinolines with NCS to yield 1-chloroalkyl-, 1-(2,2-dichloroalkyl)-, and 1-(trichloromethyl)-3,4-dihydroisoquinolines which serves as suitable precursors for the synthesis of functionalized isoquinolines by aromatization with alkoxide involving sequential 1-4,dehydrochlorination, tautomerization, and nucleophilic substitution. 1-Vinylisoquinoline and 1-methylisoquinolines could be synthesized selectively depending on the substitution pattern on position 1.8 (Chemical Equation Presented) (E) Yadav et al. have developed a simple, environmentally benign, and practical protocol for the selective synthesis of a-keto thioethers in excellent yields via αsulfenylation of ketones with thiophenols mediated by NCS. 9 (Chemical Equation Presented) (F) The thiourea-catalyzed regioselective synthesis of the chlorohydrins has been developed by Bentley et al. with NCS chlorination of olefins in the presence of water. Different olefins, such as styrenes, aliphatic olefins, stilbenes, chalcones, and indenes were found tolerable under the optimized reaction conditions.10 (Chemical Equation Presented) (G) α-Thio-β-chloroacrylamide analogues have been synthesized by treatment of a-thioamides with NCS.11 Different substituents, such as aryl and alkylthio as well as primary, secondary and tertiary amides have been employed. In most cases, the chloroacrylamides were formed exclusively as Z-stereoisomers; however, with tertiary propanamides or with amides derived from butanoic or pentanoic acid a mixture of E- and Z- isomers were formed. (Chemical Equation Presented) (H) Michael et al. have explored the application of NCS for the functional group tolerant, exo-selective synthesis of a variety of five-and six-membered ring systems via a mild and facile palladium-catalyzed intramolecular chloramination of unactivated alkenes under mild conditions.12 Various valuable acid sensitive groups were tolerated under the reaction conditions. (Chemical Equation Presented) (I) A mild approach for the synthesis of benzonitriles from corresponding benzaldehyde oximes substituted with electron-donating groups using NCS and pyridine has been developed by Gucma and Golebiewski.13 However, benzaldehyde oxime and oximes of aliphatic aldehydes are deprotected to the parent aldehydes. (Chemical Equation Presented). © Georg Thieme Verlag Stuttgart.