Chroman-4-one derivatives 1(a-i) were prepared by Pechman condensation of phenol or its substitutions with cinnamic acid by using polyphosphoric acid. These derivatives were reacted with hydrazine hydrate in refluxing ethanol to yield pyrazoline derivatives (2). The utility
(E)-3-Chloro-4-arylidene-2,3-dimethyl-1-phenylpyrazolidin-5-one 1(a-c) which were used as synthon for synthesis of all target compounds were prepared from the reaction of 3-chloro-2,3-dimethyl-1phenylpyrazolidin-5-one(Chlorophenazone)with aromatic aldehydes by 1,4-Michael addition. 4-Aryl-3-chloro-2,3-dimethyl-1-phenyl-2,3-dihydro-1H-pyrazolo[3,4-d]pyrimidine-6(5H)-one2(a-c) and-6(5H)-thiones 2(d-f)were prepared in low yields(40-50%) by the reaction of 1 (a-c) with urea or thiourea respectively in refluxing ethanol. The refluxing of 1(a-c)with hydrazine hydrate in presence of pyridine afford 3-chloro-4-aryl-2,3-dimethyl-1-phenyl-1,2,3,5-tetrahydropyrazolo[3,4-c]pyrazole 3(a-c). Also, 2-benzyl-4-spiro-5-chloro-1,5-dimethyl-2-phenylpyrazolidin-3-one (4) was obtained via epoxidation of 1(a) by hydrogen peroxide in presence of anhydrous sodium carbonate, the reaction of this spiro compound with hydrazine hydrate gave 3-chloro-2,3-dimethyl-1,4diphenyl-1,2,3,3a-tetrahydropyrazolo[3,4-c]pyrazole (5). Finally, the authentic samples of pyrazole (5) was prepared by the oxidation of 3(a) with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The structures of these compounds were confirmed by their physical properties in addition to the IR and UV Spectra.
2-Phenyl chroman-4-one 1(a-g) were synthesized by Pechmann condensation of proper phenol with cinnamic acid using poly phosphoric acid. Reactions of their derivatives with thiosemicarbazide were carried out using two methods, method A, using refluxing ethanol, gave low yield (17-20%). This method was modified to increase the yield using solvent free microwave irradiation technique, (method B), which improved the yield up to (30-40%). The treatment of these thiosemicabazones 2(a-g) with excess acetic anhydrid gave substituted thiadiazoline derivatives 3(a-g). The structure of these compounds was confirmed by IR, UV and NMR spectra in addition to their physical properties. On the other hand, the calculated values of the heat of formation and steric energy were established for compounds 2(a-g) and 3(a-g).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.