Palladium‐catalyzed carbonylative cyclization of β‐bromo‐α,β‐unsaturated carboxylic acids with 2,2‐dimethylhydrazine leading to 1‐(dimethylamino)‐1H‐pyrrole‐2,5‐diones

Abstract

β-Bromo-α,β-unsaturated carboxylic acids are carbonylatively cyclized with 2,2-dimethylhydrazine under carbon monoxide pressure in THF in the presence of a catalytic amount of a palladium catalyst along with a base to give 1-(dimethylamino)-1H-pyrrole-2,5-diones.

Palladium‐catalyzed three‐component cyclization of 2‐bromocyclohex‐1‐enecarboxylic acids with carbon monoxide and arylhydrazines leading to 2‐anilinohydroisoindoline‐1,3‐diones

“…Except for known 3a, [39] all new products prepared using the procedure outlined above were characterized spectroscopically as shown below. After the system was flushed and then pressurized with CO to 10 atm, the reaction mixture was heated to react at 120°C for 3 h. The reaction mixture was filtered through a short silica gel column (ethyl acetate) to eliminate inorganic salts.…”

“…Removal of the solvent left a crude mixture, which was separated by thin-layer chromatography (silica gel, ethyl acetate-hexane = 1:2) to give 2-(phenylamino)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione (3a; 0.069 g, 57%). Except for known 3a, [39] all new products prepared using the procedure outlined above were characterized spectroscopically as shown below.…”

“…[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Among such carbonlative cyclization reactions, we recently have shown that β-bromo-α,β-unsaturated carboxylic acids can be carbonylatively cyclized with 2,2-dimethylhydrazine under carbon monoxide pressure in the presence of a palladium catalyst to give 1-(dimethylamino)-1H-pyrrole-2,5-diones. [39] The present work arose during the course of the application of this protocol to the reaction with arylhydrazines. This report describes a facile method for the synthesis of 2-anilinohydroisoindoline-1, 3-diones by palladium-catalyzed carbonylative cyclization of 2-bromocyclohex-1-enecarboxylic acids with arylhydrazines or arylhydrazine hydrochlorides under carbon monoxide pressure.…”

Microwave‐assisted copper powder‐catalyzed coupling and cyclization of β‐bromo‐α,β‐unsaturated amides with amidine hydrochlorides leading to pyrimidinones

“…Thus, such scaffold‐containing compounds have been synthesized and tested for biological activity. During the course of our continuing studies directed towards transition metal‐catalyzed cyclization reactions of β‐bromo‐α,β‐unsaturated aldehydes and their derivatives, we have identified several new methods for the synthesis of carbocyclic and heterocyclic compounds . β‐Bromo‐α,β‐unsaturated aldehydes and their derivatives are readily prepared from α‐methylene group‐containing ketones by bromination under Vilsmeier–Haack conditions and subsequent transformation, and the products can serve as valuable building blocks for the construction of various cyclic compounds .…”