Browsing by Author "Dalal, D.S."

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Bovine serum albumin catalyzed one-pot, three-component synthesis of dihydropyrano[2,3-c]pyrazole derivatives in aqueous ethanol
(2016) Dalal, K.S.; Tayade, Y.A.; Wagh, Y.B.; Trivedi, D.R.; Dalal, D.S.; Chaudhari, B.L.
Bovine serum albumin (BSA) catalyzed synthesis of dihydropyrano[2,3-c]pyrazole derivatives via a one pot, three component reaction of an aldehyde/ketone/isatin, malononitrile and 3-methyl-1H-pyrazol-5-(4H)-one in H2O-EtOH (7: 3) at ambient temperature was developed in this work. The catalyst was found to work efficiently for aldehydes, ketones and isatins to give the corresponding dihydropyrano[2,3-c]pyrazole and spiro[indoline-3,4?-pyrano[2,3-c]pyrazole] derivatives in high yields. BSA showed a broad range of catalytic promiscuity towards various aldehydes, aromatic/aliphatic ketones and substituted isatins. The use of an environmentally benign protocol, reusability of the catalyst, avoidance of hazardous solvents, excellent yields, easy work up and no byproduct formation make BSA an attractive candidate for further applications as a biocatalyst. The Royal Society of Chemistry.
Bovine serum albumin catalyzed one-pot, three-component synthesis of dihydropyrano[2,3-c]pyrazole derivatives in aqueous ethanol
(Royal Society of Chemistry, 2016) Dalal, K.S.; Tayade, Y.A.; Wagh, Y.B.; Trivedi, D.R.; Dalal, D.S.; Chaudhari, B.L.
Bovine serum albumin (BSA) catalyzed synthesis of dihydropyrano[2,3-c]pyrazole derivatives via a one pot, three component reaction of an aldehyde/ketone/isatin, malononitrile and 3-methyl-1H-pyrazol-5-(4H)-one in H2O-EtOH (7: 3) at ambient temperature was developed in this work. The catalyst was found to work efficiently for aldehydes, ketones and isatins to give the corresponding dihydropyrano[2,3-c]pyrazole and spiro[indoline-3,4?-pyrano[2,3-c]pyrazole] derivatives in high yields. BSA showed a broad range of catalytic promiscuity towards various aldehydes, aromatic/aliphatic ketones and substituted isatins. The use of an environmentally benign protocol, reusability of the catalyst, avoidance of hazardous solvents, excellent yields, easy work up and no byproduct formation make BSA an attractive candidate for further applications as a biocatalyst. © The Royal Society of Chemistry.
Highly Efficient Regioselective Synthesis of 2-Imino-4-oxothiazolidin-5-ylidene Acetates via a Substitution-Dependent Cyclization Sequence under Catalyst-Free Conditions at Ambient Temperature
(2015) Wagh, Y.B.; Kuwar, A.S.; Patil, D.R.; Tayade, Y.A.; Jangale, A.D.; Terdale, S.S.; Trivedi, D.R.; Gallucci, J.; Dalal, D.S.
A green and efficient method for the synthesis of newer 2-imino-4-oxothiazolidin-5-ylidene acetate derivatives under catalyst-free conditions by simply stirring symmetrical and unsymmetrical 1,3-diarylthioureas with dialkyl acetylenedicarboxylates in ethanol at room temperature has been developed. Interestingly, the regioselective synthesis affords the 2-imino-4-oxothiazolidin-5-ylidene acetate derivatives: the amine nitrogen bonded to an electron-withdrawing substituent becomes part of the imino component, and the amine nitrogen bonded to an electron-donating substituent becomes the heterocyclic nitrogen. This is the first report wherein the impact of substituents in directing the regiocyclization has been explained and the structure conflict resolved by single-crystal X-ray analysis. 2015 American Chemical Society.
Highly Efficient Regioselective Synthesis of 2-Imino-4-oxothiazolidin-5-ylidene Acetates via a Substitution-Dependent Cyclization Sequence under Catalyst-Free Conditions at Ambient Temperature
(American Chemical Society service@acs.org, 2015) Wagh, Y.B.; Kuwar, A.S.; Patil, D.R.; Tayade, Y.A.; Jangale, A.D.; Terdale, S.S.; Trivedi, D.R.; Gallucci, J.; Dalal, D.S.
A green and efficient method for the synthesis of newer 2-imino-4-oxothiazolidin-5-ylidene acetate derivatives under catalyst-free conditions by simply stirring symmetrical and unsymmetrical 1,3-diarylthioureas with dialkyl acetylenedicarboxylates in ethanol at room temperature has been developed. Interestingly, the regioselective synthesis affords the 2-imino-4-oxothiazolidin-5-ylidene acetate derivatives: the amine nitrogen bonded to an electron-withdrawing substituent becomes part of the imino component, and the amine nitrogen bonded to an electron-donating substituent becomes the heterocyclic nitrogen. This is the first report wherein the impact of substituents in directing the regiocyclization has been explained and the structure conflict resolved by single-crystal X-ray analysis. © 2015 American Chemical Society.