Facile synthesis of 1-substituted 2-amino-3 …
T1 - Facile synthesis of 1-substituted 2-amino-3-cyanopyrroles
Pyrroles are widely distributed in nature and important biologically active molecules. The reaction of amines with 2,5-dimethoxytetrahydrofuran is a promising pathway for the synthesis of pharmacologically active pyrroles under microwave irradiation.
Polystyrenesulfonate-catalyzed synthesis of novel pyrroles through ..
Microwave-induced polystyrenesulfonate-catalyzed synthesis of pyrroles from amines and 2,5-diemthoxytetrahydrofuran has been accomplished with excellent yield. This method produces pyrroles with polyaromatic amines.
A Facile synthesis of chromeno[4,3-d] pyrroles derived ..
The present procedure for the synthesis of N-polyaromatic substituted pyrroles will find application in the synthesis of potent biologically active molecules.
methanes and Synthesis of Pyrroles Catalyzed by N-Chloro ..
N2 - A new method for the synthesis of 2,4- and 2,3,4-substituted pyrroles in two or three steps from commercially available ketones and allyl hydroxylamine is described. An iridium-catalyzed isomerization reaction has been developed to convert O-allyl oximes to O-vinyl oximes, which undergo a facile [3,3] rearrangement to form 1,4-imino aldehyde Paal-Knorr intermediates that cyclize to afford the corresponding pyrroles. Optimization and examples of the isomerization and pyrrole formation are discussed.
pyrroles 3.3 Synthesis of substituted ..
Synthesis of pyrroles with polyaromatic amines has not been reported. High-power microwave irradiation or considerable amounts of acids under anhydrous conditions are always necessary in the Paal-Knorr reaction. Therefore, mild reaction conditions that can overcome some of the shortcomings of previous methods are necessary. In continuation of our research on environmentally benign reaction and biological evaluation of various polyaromatic compounds as novel anticancer agents [-], we have investigated Paal-Knorr reaction using aqueous polystyrenesulfonate. After various experimentations, we have identified polystyrenesulfonate as a good catalyst for the preparation of pyrroles starting from amines and 1,4-diketo compound. Several amines including monocyclic, bicyclic, tricyclic, and tetracyclic aromatic amines were used. The other starting material was commercially available 2,5-hexanone (acetonylacetone) (Figure ). At the beginning of the procedure, the diketo compound (2), the amine (1) and polystyrenesulfonate were added in ethanol. The mixture was then stirred at room temperature for 2 h-overnight depending upon the nature of the aromatic amines. The reaction mixture was basified with aqueous sodium bicarbonate solution and extracted with dichloromethane. The organic layer was then washed with brine, dried with sodium sulphate and evaporated. The yields of the products are shown in the Table . The less basic aromatic amines needed longer reaction time although the yields are comparable to the more basic amino compounds.