An Efficient Synthetic Access to Substituted Thiazolyl‐pyrazolyl‐chromene‐2‐ones from Dehydroacetic Acid and Coumarin Derivatives by a Multicomponent Approach

Abstract

Two new series of pyran‐ or coumarin‐substituted thiazolyl‐pyrazole‐chromen‐2‐one derivatives 10a–10d and 11a–11d were efficiently synthesized under environmentally friendly reaction conditions through a convenient one‐pot multicomponent reaction of a heterocyclic bromoacetyl derivative 3 or 4 with thiosemicarbazide and a substituted 3‐(acetoacetyl)coumarin derivative 5a–5d in anhydrous ethanol. The reaction proceeds through Hantzsch thiazole and Knorr pyrazole syntheses in refluxing ethanol. The key features of this approach are its operational simplicity, the quick access to the desired products, and the good to excellent yields. The structures of the newly synthesized compounds were established by IR spectroscopy, 1H, 13C, and 2D NMR spectroscopy, and mass spectrometry.

Discovery of 2,4-thiazolidinedione-tethered coumarins as novel selective inhibitors for carbonic anhydrase IX and XII isoforms

“…Unless otherwise mentioned, all reagents and solvents are commercially available and have been used without further purification. Compounds 2 and 3 are previously reported [ 25 , 26 ].…”

Synthesis and Biological Properties of Coumarin Derivatives. A Review

“…In the presence of melamine-modified chitosan (Cs-Pr-Me) materials as a reusable bifunctional organocatalyst, Valiey et al [94] performed a green protocol to synthesize benzylpyrazolyl coumarin derivatives by reacting arylaldehydes, ethyl acetoacetate, hydrazine derivatives, malononitrile and 4-hydroxycoumarin, Scheme 67. Hamdi et al [95] synthesized 4-aryl-6-methyl-5-(2-oxo-2Hchromene-3-carbonyl)-3,4-dihydropyrimidin-2(1H)-one / thiones from 3-acetoacetylcoumarin, benzaldehyde and urea/thiourea in CH 3 CN in the presence of sulfuric acid, Scheme 68.…”

“…Hamdi et al [95] . synthesized 4‐aryl‐6‐methyl‐5‐(2‐oxo‐2H‐chromene‐3‐carbonyl)‐3,4‐dihydropyrimidin‐2(1 H )‐one / thiones from 3‐acetoacetylcoumarin, benzaldehyde and urea/thiourea in CH 3 CN in the presence of sulfuric acid, Scheme 68.…”

3-(Bromoacetyl)coumarins: unraveling their synthesis, chemistry, and applications

“…143 Microwave irradiation was reported as a green chemistry method for the synthesis of coumarin-3-yl-thiazol-3-yl-1,2,4- 149 Series of pyrazoles bearing coumarin moieties 148 were prepared underwent Hantzsch cyclocondensation of 3-(bromoacetyl)coumarin 1, thiosemicarbazide 112 and various 3-(acetoacetyl) coumarins 147 in reuxing ethanol (Scheme 63). 150 One pot, three-component reaction of chalcones 149, thiosemicarbazide 112, and different substituted 3-(bromoacetyl) coumarin derivatives 1 in reuxing ethanol containing catalytic amount of aqueous sodium hydroxide was achieved as an effective route for the synthesis of 4,5-dihydro-3,5-diphenylpyrazol-1-thiazol-4-2H-chromen-2-one derivatives 150a-l in one step (Scheme 64). 149 In the same fashion, Ghodsi 6.…”