NISCAIR Online Periodicals Repository Collection: IJC-B Vol.49B(04) [April 2010]

Synthesis of new isoxazolyl coumarins by eco-friendly dipyridine cobalt chloride catalyzed Pechmann reaction at ambient temperature

Title: Synthesis of new isoxazolyl coumarins by eco-friendly dipyridine cobalt chloride catalyzed Pechmann reaction at ambient temperature

Authors: Rajanarendar, E; Shaik, Firoz Pasha; Reddy, M Nagi

Abstract: Dipyridine cobalt chloride is used as an alternative conventional Lewis acid catalyst in the Pechmann condensation of isoxazolyl phenols with β-ketoesters leading to the formation of isoxazolyl coumarins. The method is simple, cost-effective and at ambient temperature gives good yields.

Page(s): 532-535

Facile synthesis of acyclic analogues of carbocyclic nucleoside as potential anti-HIV pro-drug

Title: Facile synthesis of acyclic analogues of carbocyclic nucleoside as potential anti-HIV pro-drug

Authors: Siddiqui, Ibadur R; Singh, Pravin K; Srivastava, Vishal; Singh, J

Abstract: Microwave induced montmorillonite K 10 clay catalyzed Michael addition of sulphur nucleophile, (4-oxo-butyl)-dithiocarbamic acid 1 to 4-arylidene-5(4H)-oxazolones 2a-j followed by ring transformation of the resultant Michael adducts 3a-j in solvent-free conditions gives 4a-j in excellent yield. Coexistence of acidic and basic sites on surface of montmorillonite K 10 accelerates the organic reactions synergistically. The control Aldol condensation of compound 4a-j with HCHO gives compound 5a-j, which upon chemoselective reduction with NaBH₄ gives the title compound 6a-j. This process minimizes the mechanical loss of the intermediate during the process of isolation, and thus increases the yield and decreases the cost and time.

Page(s): 512-520

Development and assessment of green synthesis of hydrazides

Title: Development and assessment of green synthesis of hydrazides

Authors: Saha, Ajoy; Kumar, Rajesh; Kumar, Rajendra; Devakumar, C

Abstract: An expeditious, solvent free one pot method for the preparation of hydrazides from corresponding acids directly under microwave irradiation is developed. The method has been assessed using green chemistry measures and found superior to conventional method with higher E(environmental) factor, atom economy, atom efficiency, carbon efficiency, reaction mass efficiency.

Page(s): 526-531

Synthesis and study of chlorosubstituted 4-aroyl and 4-alkoyl-pyrazolines, pyrazoles and their effect on some flowering plants

Title: Synthesis and study of chlorosubstituted 4-aroyl and 4-alkoyl-pyrazolines, pyrazoles and their effect on some flowering plants

Authors: Mahale, Jaishree D; Manoja, S C; Belsare, N G; Rajput, P R

Abstract: Some new chlorosubstituted 4-aroyl/alkoylpyrazolines 5a,b and 4-aroyl/alkoylpyrazoles 7a,b have been synthesized by condensation of 1-(2′-hydroxy-3′-5′-dichlorophenyl)-3-aryl/alkyl-1-3-propanedione 3a,b and valeraldehyde by Baker-Venkatraman transformation of corresponding aroyl/alkoyloxyacetophenones. Aroyl/Alkoyloxyacetophenones 2a,b undergo intramolecular Claisen condensation to form 1-(2′-hydroxy-3′-5′-dichlorophenyl)-3-aryl/alkyl-1,3-propanediones 3a,b which on treatment with aliphatic aldehyde in ethanol containing little piperidine forms 3-aroyl/alkoylchromanones 4a,b. From these 3-aroyl/alkoylchromanones 4a,b 4-aroyl/alkoylpyrazolines 5a,b are synthesized. 3-Aroyl/Alkoylchromanones 4a,b are converted into 3-aroyl/alkoylchromones 6a,b. The 3-aroyl/alkoylchromones 6a,b on treatment with Ph.NHNH₂.HCl in dioxane containing small amount of piperidine furnish 4-aroyl/alkoylpyrazoles 7a,b. The structures of the newly synthesized chlorosubstituted 4-aroyl /alkoylpyrazolines 5a,b and 4-aroyl/alkoylpyrazoles 7a,b have been elucidated on the basis of spectral analysis and their homogeneity has been established by TLC.

Page(s): 505-511