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Part-IIImpact of Microwave…A facile microwave assisted protocol has been described for the fast generation of 2-arylbenzopyrano[2,3-c]pyrazol-3-one library, 38 of 144 compounds, utilizing highlyreactive 2-iminocoumarines or the corresponding hydrazines, as starting materials.Microwave irradiation of the reaction mixture in the acetic acid led to one pot synthesis ofthe desired compounds in 43-87% yields and 90-100% purity. 41H 2 NNHR 2 , MWI, 190 o C, 15 minOOOR 1NH 2R 1ONNH 2R 1ONNR2ONHH 2 NNHR 2 , MWI,80 o C, 2 minHNR 2MWI,190 o C,5 min38R 1 = H, 8-OMe, 6-Cl, 7-OH etc.R 2 = H, 4-NO 2 Ph, 4-OCH 3 Ph,4-Br, Bn, t-BuA sequential one-pot two-step protocol for microwave-assisted Hantzsch-type synthesisof hexa substituted 1,4-dihydropyridines 39 has been developed 42 (33 compounds). Thethree-component condensation of β-aroylthioamides, aldehydes and acetonitriles followedby the in situ S-alkylation of the intermediates afforded the hexasubstituted 1,4-dihydropyridines.OOOOR 1NHPhR 2+CNHEt 3 N, KI, KOH, R 4 XMWIR 2R 3 R 1H N SR 42 NR 339R 1 = H, 4-Cl, 4-CH 3R 2 = Ph, 4-ClPh, 4-OCH 3P h, 3-NO 2 Ph, CH 3 etcR 3 = CN, COOEtR 4 =C 4 H 9 , CH 2 PhZhou et al. 43 have synthesized sixty compounds containing 4-thiazolidinone 40 & 41 and4-thiazinanone 42 & 43 cores with biaryl and thioaryl substitutions using a microwave-292