A new era in the organic synthetic world is demanding greener protocols for the execution of reactions.

An easy, facile and mild approach of liquid assisted grinding for the synthesis of novel dihydrobenzo[f]pyrano[3,2-c]chromenone derivatives using multicomponent cascade is herein described. The advantages of this protocol is one pot strategy, high reaction throughput, excellent yields, diversified scope, excellent score of green matrices. In addition, synthesis of bis (benzo[f]chromen-3-one) derivatives under microwave irradiation have also been established. The current methods utilize DABCO as a catalyst in forging these bioactive molecules. Also, all the final products are obtained by mere filtration, and the reaction conditions do not require any harsh reagents or typical work up.

Herein, synthesis of benzothiazoles via decarboxylative cross-coupling between α-keto acids and 2aminothiophenols under blue LED irradiation without using any photocatalyst or metal at room temperature is described. The formation of benzothiazole is driven by the EDA (electron donor-acceptor) complex formed between α-keto acid and 2-aminothiophenol. This methodology gives easy access to 2-substituted and -unsubstituted benzothiazoles in moderate to good yields. α-Keto acids and 2-aminothiophenols bearing different functional groups were easily transformed under the given conditions.

Photocatalytic amidation of α-keto aldehydes is herein investigated. This transformation was achieved using rose bengal as photocatalyst at room temperature under ambient air and under irradiation of a 20 W white LED bulb. The method is mild, efficient and environmentally benign. This photocatalytic method is compatible with different unsubstituted and substituted α-keto aldehydes having electron-withdrawing or -donating groups, secondary amines, cyclic or acyclic, and primary aliphatic amines. Mechanistic studies reveal that the reaction proceeds via oxidative quenching of the photocatalyst.

Quinoline is an N-heterocyclic privileged scaffold that finds immense applications in biological domains and material sciences. For example, it acts as antimalarial, anti-inflammatory, antiparasitic, antiviral, and anticancer agents. The nucleus...