Process optimization and eco-friendly/greener synthesis of some n-aryl/heteryl acetoacetamides

Abstract

N-aryl/heteryl acetoacetamides are the intermediates used in the synthesis of various heterocyclic compounds like 1,4-dihydropyridines, pyrimidines etc. Three different substituted N-aryl/heteryl acetoacetamide derivatives (I-III) have been prepared from the reaction of ethylacetoacetate and three different aryl/heteryl primary amines under solvent free conditions using potassium tert-butoxide as catalyst. The reactions were carried out by two different methods (viz., Conventional and Microwave irradiation) and they are simple, eco-friendly and economical. All reactions were processed for optimization with different ratios of aryl/heteryl amine and ethylacetoacetate like1:1,1:1.2,1:1.4,1:1.6,1:1.8,1:2 and a comparison was made between the percentage yields with each ratio. Highest percentage yield was observed with 1:1.8 ratio for I & II and 1:1.6 ratio for III in both the methods. However, the microwave irradiation method was found to be superior to the conventional method. The newly synthesized compounds have been purified by recrystallization and characterized by physical and spectral data.DOI: http://dx.doi.org/10.3329/icpj.v2i11.16533 International Current Pharmaceutical Journal, October 2013, 2(11): 189-192

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“…5 In further years, improvement in Biginelli compounds is done by using different catalysts such as polyphosphate ester (PPE) 6 , Bronsted acids viz. p-toluenesulfonic acid 7 , potassium hydrogen sulphate 8 , chloroacetic acid 9 , titanium (IV) chloride 10 , ruthenium (III) chloride 11 , scandium (III)triflate 12 , Iodine-alumina 13 ,Cobalt(II)acetate 14 ,sulphated zirconia 15 , ferric chloride hexahydrate 16 , MgBr 2 17 , nbcl 5 18 , Lewis acids 19,20 viz. Yb (OTf) 3 21 , InCl 3 22 , CuCl 2 23 , SnCl 2 24 , BF 3 .OEt 2 25 , ZrCl 4 26 , L-proline 19 , L-proline methylester hydrochloride 27 , ZnCl 2 28, 29 , Zinc sulphamate 30 , combination catalytic system such as tin chloridelithium chloride 31 , cupric chloride-lithium chloride 32 , ferric chloride/tetraethyl orthosilicates 33 , Trimethylsilyl triflate 34 , strontium(II)triflate 35 , cadmium chloride 36 , methanesulfonic acid 37 , Iron(III) 38 , (AlCl 3 +KI) 39 , bimetal system , Cupy 2 Cl 2 40 , Samariumdiiodide 41 .…”