Silica gel Catalyzed Synthesis of Quinophthalone Pigments Under Solvent-Free Conditions Using Microwave Irradiation

Abstract

Condensations of anhydrides and quinaldine derivatives are accelerated by microwave irradiation under solvent free conditions in the presence of silica gel as catalyst.

More Sustainable Approaches for the Synthesis of N-Based Heterocycles

“…The preparation of quinophthalones can be achieved through the condensation of anhydrides and quinoline derivatives by microwave irradiation in presence of silica gel as catalyst. This inorganic support proved to be the best among others (alumina, montmorillonite K-10 clay) yielding the desired compounds in good to excellent yields (Table ) . A fused imide with a quinoline ring can also be prepared under MWI and solvent-free conditions by reaction of a fused quinoline anhydride with a primary amine in wet K-10 clay, while the quinoline-related acridines can be obtained by reaction of dicarboxylic acids or arylacetic acids with diphenylamine in a microwave oven, with zinc(II) chloride in high excess …”

“…This inorganic support proved to be the best among others (alumina, montmorillonite K-10 clay) yielding the desired compounds in good to excellent yields (Table 105). 717 A fused imide with a quinoline ring can also be prepared under MWI and solvent-free conditions by reaction of a fused quinoline anhydride with a primary amine in wet K-10 clay, 718 while the quinoline-related acridines can be obtained by reaction of dicarboxylic acids or arylacetic acids with diphenylamine in a microwave oven, with zinc(II) chloride in high excess. 719 For the preparation of dihydroquinolines, there are three methods that can be successfully employed.…”

Phthalic anhydride (PA): a valuable substrate in organic transformations

“…Loghmani-Khouzani in 2004 also gained some quinophthalones ( 7 ) via the microwave-assisted (700 W) reaction of PA ( 1 ) and 2-methylquinolines ( 6 ) in a 1 : 1 molar ratio in the presence of silica gel (silica gel 60, 230–240 mesh Merck, 300 mg) within 2 min by 85–97%. 101…”