Ultrasound-Assisted Sequential Multicomponent Strategy for the Combinatorial Synthesis of Novel Coumarin Hybrids

Abstract

The present investigation reports an easy access to a library of novel spiro-oxindole-pyrrolizine or pyrrolo[1,2-c]thiazole fused coumarin hybrid heterocycles through a one-pot sequential four-component reactions of 2,2-dimethyl-1,3-dioxane-4,6-dione, salicylaldehydes, isatins, and cyclic α-amino acids under ultrasound irradiation.

Activator free diastereoselective 1,3-dipolar cycloaddition: a quick access to coumarin based spiro multi heterocyclic adducts

“…The structure and stereochemistry of 3aa was confirmed and assigned by 1 H NMR, 13 C NMR and X-ray crystallography analysis ( Scheme 2 ). Based on previous reports 6 and X-ray crystal analysis, the dipole configured aza-ylide interacts with coumarin dipolarophile in endo -mode. This endo -mode approach led to a single diastereomer product in cycloaddition reaction.…”

“…provides these spiro cyclic heterocyclics ( Scheme 1a ) with an additional ring system. 6 Nevertheless, huge scope in this topic is awaited for the production of new chemical entities using multiple raw materials in one operation. Further, these approaches avoid prefunctionalizations of reactive centres, which is an obvious demand in the green synthesis 7 research area.…”

One‐pot four component condensation for the synthesis of novel dispirooxindole pyrrolidine linked 1,2,3‐triazoles via stereo‐ and regioselective [3 + 2] cycloaddition reaction in PEG‐400

“…2‐[2‐oxo‐1‐(prop‐2‐ynyl)indolin‐3‐ylidene]malononitrile undergoes [3 + 2] cycloaddition with azides in the presence of Cu(I) to give triazole intermediates (6). Isatin on the other hand, undergoes condensation with sarcosine to give a spiro intermediate 7 which undergoes decarboxylation to give the reactive ylide 8 . This reactive ylide 8 can undergo [3 + 2] cycloaddition with 6 by two ways, path a and path b to give the products 5 and 9, respectively.…”

Regio‐ and Stereoselective Multicomponent Synthesis of Novel Chromeno‐Annulated Pyrrolizine and Thiazolizine Scaffolds via 1,3‐Dipolar Cycloaddition Reactions

“…To report further, Matsuya and co‐workers have depicted the synthesis of pyrrolizines in (Scheme b) . Again, Kanchithalaivan and Kumar's group has developed a method for the synthesis of spiro‐oxindole pyrrolizines derivatives shown in (Scheme c) …”