Bischalcones—synthons for a new class of bis(heterocycles)

Abstract

Novel oxo-linked bis(heterocycles) containing two different heterocyclic rings, viz. pyrroles in combination with pyrazolines and isoxazolines, are synthesized.

Synthesis and bioassay of pyrrolyl oxazolines and thiazolines

“…This compound was prepared by the reaction of 1-arylsulfonyl-2-chloroethene with mercaptoacetic acid followed by oxidation and esterification [26]. Earlier we have reported the synthesis of 2-arylsulfonylmethyl oxazolines/thiazolines and 2-arylmethanesulfonylmethylsulfonyl oxazolines/thiazolines by the traditional four-step three-intermediate route from arylsulfonylacetic acid methyl ester [27]. We have also reported one pot methodology to develop these heterocycles exploiting lanthanide amino alkoxide complexes as reagents [28].…”

Synthesis and Antioxidant Activity of Amido‐Linked Benzoxazolyl/Benzothiazolyl/Benzimidazolyl‐Pyrazoles and Isoxazoles

“…The dipolar reagents can be generated by the dehydrogenation of araldehyde hydrazones and araldoximes with lead tetraacetate , mercury acetate , 1‐chlorobenzotriazole , chloramine‐T (CAT) , etc. In fact, we have reported novel oxo‐linked bis heterocycles by 1,3‐dipolar cycloaddition of dipolar reagents viz ., TosMIC, diazomethane, nitrile imines and nitrile oxides to symmetrical and unsymmetrical bischalcones . It is well known that the combination of two or more heterocycles in a single molecule could afford a novel entity with increased bioactivities .…”

Synthesis and Bioassay of Oxazolyl/Thiazolyl Selenadiazoles, Thiadiazoles and Diazaphospholes

“…In fact, the preparation of oxazolines and thiazolines was reported by the traditional four step three intermediate route. 5) However, a onepot methodology was developed for the preparation of oxazolines and thiazolines from the sulfonylacetic acid methyl esters exploiting lanthanide chemistry. 1,6) Indeed this method provides a simple and elegant route to develop oxazolines and thiazolines directly from carboxylic esters.…”