Tuning the Chemoselectivity of Dehydroacetic Acid Derived Enones by Isoniazid and Phenylhydrazines: An Efficient Access to 3‐Styryl Pyrano[2,3‐c]pyrazolones

Abstract

The first‐time reported nitrogen source‐based chemoselectivity of dehydroacetic acid (DHA)‐derived enones has been tuned by isoniazid (INH), and phenylhydrazines respectively. When INH a first‐line antitubercular drug, was employed as a new surrogate for nitrogen source, preferentially unconventional 1,3‐dicarbonyl addition occurred, providing a series of fused 3‐styryl pyrano[2,3‐c]pyrazolones in good yields. While in the presence of phenylhydrazines and molecular iodine, the reaction was proceeded via oxidative annulation across enone framework, resulting in the efficient and straightforward access to 3‐pyrazolyl pyranones.

From 2011 to 2022: The development of pyrazole derivatives through the α,β‐unsaturated carbonyl compounds

“…Kumar's group [51] reported first time nitrogen‐based chemoselective reaction of dehydroacetic acid (DHA) derived enones 1 , which was tuned by isoniazid (INH) and phenylhydrazines 2 , respectively. The reaction was carried out by oxidative annulation across the enone framework when phenylhydrazines 2 and molecular iodine were present, resulting in the quick and easy access to 3‐pyrazolyl pyranones 91 – 92 .…”

A novel pyrazoline-based turn-on fluorescent probe for highly sensitive detection of Al3+ in aqueous solution and its applications

“…The probe was synthesized by an unsophisticated two-step reaction as the reported method (Scheme 1) (Saidoun et al 2018;Swarnkar et al 2020). Firstly, the Clayson-Schmidt type with dehydroacetic acid and cinnamaldehyde is legally condensed and compound 1 is easily synthesized.…”

Visible-Light-Induced Tertiary C(sp3)–H Sulfonylation: An Approach to Tertiary Sulfones

“…Many reports have been discussed for remote or direct C­(sp 3 )–H sulfonylation at primary and secondary carbon centers, − but the construction of tertiary sulfones via C­(sp 3 )–H sulfonylation without prefunctionalization remains a formidable challenge for its synthetic approaches. In continuation of the efforts of our laboratory in the development of novel protocols for medicinally important scaffolds − and as a first example of our strategy, we sought to disclose a visible-light-induced novel tertiary C­(sp 3 )–H bond sulfonylation approach with the successful application of the cost-effective and simple organic dye Na 2 -Eosin Y as a photocatalyst for the synthesis of elusive tertiary sulfones. Several reports have been uncovered with this concern (Scheme ).…”