S. D. Jadhav

Green Approach for Knoevenagel Condensation of Aromatic Aldehydes with Active Methylene Group

Abstract An ecofriendly and economical method of Knoevenagel condensation of aromatic aldehydes with malononitrile catalyzed by lemon juice, a natural catalyst, in the absence of any solvent is described. GRAPHICAL ABSTRACT

Calcined eggshell (CES): An efficient natural catalyst for Knoevenagel condensation under aqueous condition

AbstractA convenient, eco-friendly and economic method for Knoevenagel condensation of aromatic aldehydes with active methylene compounds using calcined eggshell (CES) as an efficient natural catalyst in aqueous medium has been reported. CES is a new, ecologically safe and inexpensive green catalyst obtained from renewable resources. Graphical AbstractA convenient, eco-friendly and economic method for Knoevenagel condensation of aromatic aldehydes with active methylene compounds using CES as an efficient natural catalyst in aqueous medium has been reported here. CES is a new, ecologically safe, inexpensive and green catalyst obtained from waste eggshells.

CES as an Efficient Natural Catalyst for Synthesis of Schiff Bases under Solvent-Free Conditions: An Innovative Green Approach

A mild and efficient method has been reported for the preparation of Schiff base ligands through the condensation reaction of various aromatic aldehydes with substituted aromatic amines in the presence of CES (calcined eggshell) as a heterogeneous catalyst under solvent-free conditions. The advantages of this ecofriendly, economic method are simplicity of the reaction procedure, moderate to good product yields, and very short reaction times.

Synthesis and antimicrobial activities of new oxime carbamates of 3-aryl-2-thioquinazolin-4(3H)-one

AbstractS-alkylation of 3-aryl-2-thioquinazolin-4(3H)-one (1) with chloroacetone gave 2-(propanonyl thio)-3-arylquinazol-4(3H)ones (2). Further, the treatment of compound (2) with hydroxylamine hydrochloride gave the corresponding oximes (3) which on reaction with phenyl isocyanate in THF yielded corresponding oxime carbamates 4. The synthesized compounds have been confirmed using IR and 1H NMR, mass spectral data together with elemental analysis. All newly synthesized compounds have been tested for their antibacterial and antifungal activities. Graphical AbstractCorresponding oxime carbamates (4) were synthesized by using 3-aryl-2-thioquinazolin-4(3H)-one (1) as starting material. This step-wise conversion involves S-alkylation of 3-aryl-2-thioquinazolin-4(3H)-one and oxime formation. The compounds have been tested for their antibacterial and antifungal activities.

Bronsted acid-type biosurfactant for heterocyclization: a green protocol for benzopyran synthesis

A natural biosurfactant, a biobased green acidic catalyst for cyclocondensation of salicylaldehyde (or 2-hydroxy naphthaldehyde) and cyclic 1,3-diketones for benzopyran synthesis in water has been reported for the first time. The structures of the final compounds were confirmed with the aid of IR, 1H NMR, and 13C NMR spectroscopy. Lemon extract as a natural biosurfactant provides a micellar media for effective organic transformation. The CMC of lemon extract was determined by the conductivity method. In comparison to the conventional methods, this synthetic pathway complies with several key requirements of green chemistry principles such as the utilization of renewable feedstock, auxiliary aqueous conditions, waste prevention, and atom economy along with the use of biodegradable catalyst. Thus, the reported protocol offers an attractive option because of its ecological safety, environmental acceptance, sustainability, and low-cost straightforward work-up procedure.

Citric acid as a mild and inexpensive organocatalyst for synthesis of tetrahydrobenzo[ a ] xanthen-11-ones and dibenzo[ a,j ] xanthenes under solvent-free condition

A simple and efficient protocol has been developed for the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a] xanthen11-one derivatives, I employing a one-pot three-component reaction of aldehydes, 2-naphthol and dimedone in the presence of citric acid under solvent-free condition at 120°C. The protocol has been also extended for the synthesis of 14-aryl-14Hdibenzo [a.j] xanthenes, II by employing 1:2 proportion of aldehyde and 2-naphthol, to afford excellent yield in short reaction time.