جستجوی مقالات مرتبط با کلیدواژه « Organocatalyst » در نشریات گروه « شیمی »

This review papers aims to comprehensively address the various aspects of ionic liquids and supported ionic liquids, which constitute a significant branch within the expansive field of green catalyst. Specifically, it delves into the recent advancements made in this domain over the past three years for the synthesis of heterocyclic compounds. In the introduction section of this review, the discussion revolves around the structural diversity of ionic liquids with an acidic nature. Furthermore, the introduction presents a clear and definitive classification system for diverse types of acidic ionic liquids. In the last part of this review paper, a comprehensive literature review would be provided on the application of ionic liquids and supported ionic liquids for the synthesis of heterocyclic compounds. The primary objective of this review is to present a comprehensive perspective on the utilization of ionic liquid and supported ionic liquid in the synthesis of various heterocyclic compounds. Special attention is given to the pivotal role played by reusable supported ionic liquids in this process.

The analog of 4-aminoantipyrine (4-amino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazole-3-one), is interesting in the field of pharmacology and pharmaceutical chemistry and plays an important role as the ingredients for the production of the drugs and medicines. In the current study, a series of Schiff (including two new compounds) bases have been synthesized from 4-aminoantipyrine and substituted benzaldehydes via a simple and easy procedure in a short time with high yields. The structures of products have been characterized by (FTIR, 1HNMR, 13CNMR, and Elemental Analysis).

An effective protocol for the asymmetric synthesis of β-amino carbonyl compounds using pyrrolidine based organocatalyst has been developed via one-pot three-component Mannich reaction. The organocatalyst (S)-N-(2,4-dinitrophenyl) pyrrolidine-2-carboxamide 3b confirmed to be the superior organocatalyst in solvent acetonitrile to obtain corresponding products in up to 89% yield and with excellent ee (90%). This organocatalytic reaction reveals productive result with a range of other aldehydes. Aromatic aldehydes having electron withdrawing substituent show the best results. Excellent yields, high enantioselectivity, mild reaction condition, and simple experimental work-up procedure are some of the advantages of this method.

In this work, we have reported the preparation of pyrano[2,3-d]pyrimidine dione derivatives by the tandem Knoevenagel-Michael-cyclocondensation reaction of malononitrile, various aldehydes and barbituric acid derivatives at the presence of isonicotinic acid as an efficient organocatalyst.

Simple and efficient protocols have been developed for the one-pot synthesis of aryl-14H-dibenzo[a,j]xanthenes and 1,8-dioxo-octahydro-xanthenes. (i) A cost-effective, simple and convenient procedure for the synthesis of aryl-14H-dibenzo[a,j]xanthenes has been developed via a one-pot condensation from substituted benzaldehydes (1 equiv) and β-naphthol (2 equiv) in the presence of 2,6-pyridinedicarboxylic acid (2,6-PDCA) under solvent-free conditions. (ii) The one-pot condensation of substituted benzaldehydes (1 equiv) and 5,5-dimethyl-1,3-cyclohexanedione (dimedone) (2 equiv) in the presence of 2,6-pyridinedicarboxylic acid (2,6-PDCA) under solvent-free conditions leads to 1,8-dioxo-octahydro-xanthenes. In these protocols several advantages such as: Excellent yields, very short reaction times, easy work-up, simple methodology and ease of preparation and regeneration of the catalyst are offered. In these protocols several advantages such as: Excellent yields, very short reaction times, easy work-up, simple methodology and ease of preparation and regeneration of the catalyst are offered.

A simple, highly efficient and green procedure for the condensation of o-phenylenediamines with 1, 2-dicarbonyl compounds in the presence of vitamin C, as an inexpensive organocatalyst, is described. Using this method, variety of quinoxaline derivatives with different electron releasing and electron withdrawing substituents, are produced in high to excellent yields at room temperature in ethanol. The remarkable features of this new protocol are high to excellent conversions, relatively short reaction times, and clean reaction profiles, simple and easy experimental and work-up procedures. Thus we have been able to report another ability of vitamin C in organic chemistry synthesis which has less disastrous effect in the atmosphere and human survival.

A new organocatalyzed method is developed for Baylis–Hillman reactions of cyclohex-2-enone with various aromatic aldehydes in the presence of water and catalytic quantities of triethylamine. All reactions take place at room temperature and relatively good yields of various products are obtained within a time frame which does not exceed 24 hours. The mild reaction conditions used in the present method and the versatility of the process are the main advantages of this procedure. As a result, products of the Baylis–Hillman reaction of cyclohex-2-enone with various aromatic aldehydes bearing electron withdrawing and electron releasing groups are obtained under inexpensive organocatalytic conditions.

Organocatalyst trityl chloride (Ph3CCl), by in situ formation of trityl carbocation with inherent instability, efficiently catalyzes the condensation of dimedone (5,5-dimethyl-1,3-cyclohexanedione) (2 equiv.) with arylaldehydes (1 equiv.) under solvent-free conditions to afford 9-aryl-1,8-dioxo-octahydroxanthenes in high to excellent yields and in relatively short reaction times. Formation of the carbocationic system is confirmed by studying IR, 1H NMR and UV spectra according to the literature. Moreover, a plausible mechanism based on the literature and observations is proposed for the reaction.