Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction

Abstract

An efficient approach for the synthesis of pyrazolopyridines containing the aminochromane motif through a base-catalyzed cyclization reaction is reported. The synthesis was carried out through a three-component reaction of (arylhydrazono)methyl-4H-chromen-4-one, malononitrile, primary amines in the presence of Et3N at room temperature. However, carrying out the reaction under the same conditions without base led to a fused chromanyl-cyanopyridine. High selectivity, high atom economy, and good to high yields in addition to mild reaction conditions are the advantages of this approach.

Recyclization of morpholinochromonylidene–thiazolidinone using nucleophiles: facile synthesis, cytotoxic evaluation, apoptosis, cell cycle and molecular docking studies of a novel series of azole, azine, azepine and pyran derivatives

“…Heating of the substrate 3 with some selected amines such as 4-aminomorpholine and morpholine in absolute ethanol afforded 5-[2-(2-hydroxybenzoyl)-3-(morpholinoamino) allylidene]-2-(morpholinoimino)-3-phenylthiazolidin-4-one ( 4 ) and 5-[2-(2-hydroxybenzoyl)-3-morpholino-allylidene]-2-(morpholinoimino)-3-phenylthiazolidin-4-one ( 5 ), respectively (Scheme 2). 17 The reaction started through a nucleophilic attack at C–2 position of chromone ring by ring opening to yield these products.…”

“…16 Interestingly, the reaction of the substrate 3 with some hydrazides such as semicarbazide, thiosemicarbazide and cyanoacetohydrazide in absolute ethanol or ethanolic sodium ethoxide, was studied. In all cases, the previous product (17), respectively (Scheme 6). 20 The spectral data of both products 16 and 17 conrmed their structures (see ESI †).…”

“…Heating of the substrate 3 with some selected amines such as 4aminomorpholine and morpholine in absolute ethanol affor- (5), respectively (Scheme 2). 17 The reaction started through a nucleophilic attack at C-2 position of chromone ring by ring opening to yield these products.…”

“…The results regarding cytotoxic activities are displayed as IC 50 values in Table1. Towards human breast cancer cells (MCF-7), compounds7,11,12,15,17,19,20,22,26 …”

Facile synthesis of pyrazolopyridine pharmaceuticals under mild conditions using an algin-functionalized silica-based magnetic nanocatalyst (Alg@SBA-15/Fe3O4)

“…Other pyrazolopyridine-containing biologically-active compounds involve a GSK-3 inhibitor, and BAY 41-2272 can be utilized as cardiovascular therapeutic agents. 5 Although various multi-step procedures for the construction of pyrazolopyridines have been developed in recent years, some of them suffer from one or more challenges for instance long reaction time, low yields, laborious work-up procedure, as well as generation of by-products. It seems that the development of efficient methods for the synthesis of pyrazolopyridines is still an important topic in chemistry because of their extensive biological activities.…”