Metal-free radical nitration of the β C–H
bond of
3-alkylidene-2-oxindoles with tert-butyl nitrite
(TBN) has been explored. Interestingly, (E)-3-(2-(aryl)-2-oxoethylidene)oxindole
and (E)-3-ylidene oxindole give different diastereomers
on nitration. The mechanistic investigation revealed that the diastereoselectivity
was controlled by the size of the functional group. Another transformation
of 3-(nitroalkylidene) oxindole into 3-(tosylalkylidene) oxindole
was performed through metal and oxidant-free tosylhydrazine-mediated
sulfonation. Both methods have the advantages of readily available
starting materials and operational simplicity.
An iron-catalyst mediated one-pot multicomponent route for the synthesis of novel 6-thioxo-hexahydroindeno[1′,2′:4,5]imidazo[1,5-a]pyridin-12(6H)-one scaffolds has been developed using ninhydrin, L-proline, and aryl isothiocyanates in ethanol medium. This methodology offers an interesting [1,2] oxygen shift mechanism pathway via a number of ring-opening and ring-closing cascade steps to provide diverse substituted hexahydroindeno-imidazo[1,5-a]pyridinones in excellent to good yields. The stereochemistry of the proline ring is lost during the course of the reaction. This protocol is well acceptable toward both electron-accepting and electron-donating functionalities at the ortho-, meta-, and para-positions of the isothiocyanate moiety. Nonhazardous conditions, step economic, and easy operational process are the advantages of this methodology.
Our study describes a new development featuring iodine-catalyzed two consecutive oxidative cross-coupling reactions involving Cα(sp3)-H of benzyl amines followed by intramolecular cyclization in water under air. Here the C-N coupling...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.