Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[]chromeno[2,3-]quinoxalinoporphyrins.

A facile one-pot four-component synthetic methodology is evolved to construct novel copper(II) benzo[]chromeno[2,3-]quinoxalinoporphyrins in good yields via a sequential reaction of copper(II) 2,3-diamino-5,10,15,20-tetraarylporphyrins, 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes, and dimedone in the presence of a catalytic amount of trichloroacetic acid in chloroform at 65 °C. Further, the newly prepared copper(II) porphyrins were transformed to the corresponding free base and zinc(II) benzo[]chromeno[2,3-]quinoxalinoporphyrins under standard demetallation and zinc insertion conditions. The absorption and emission properties of the obtained porphyrins were investigated by using UV-visible and fluorescence spectroscopy.

Synthesis and antimalarial activity of 7-chloroquinoline-tethered sulfonamides and their [1,2,3]-triazole hybrids.

Drugs with multiple bioactive moieties have the advantages of multiple modes of action and fewer chances of drug resistance. In continuation of our previous work of developing hybrid antimalarials, we present herein the synthesis and antimalarial activity of two different series of 7-chloroquinoline-sulfonamide hybrids. The first series of compounds were synthesized by using -dodecylbenzenesulfonic acid as a Bronsted acid catalyst in ethanol.

Construction of coumarin-fused pyrido[2,3-b]porphyrins through a trichloroacetic acid-accelerated domino approach.

The first synthesis to construct coumarin-fused pyrido[2,3-b]porphyrins has been accomplished via a cascade reaction of 2-amino-meso-tetraphenylporphyrins, aromatic aldehydes and 4-hydroxycoumarin in o-dichlorobenzene containing a stoichiometric amount of trichloroacetic acid under reflux conditions. The methodology presented herein provides a direct access to a new series of π-extended nickel(ii) and copper(ii) porphyrin analogues in 58-69% isolated yields under one-pot operation. Furthermore, coumarin-fused copper(ii) pyrido[2,3-b]porphyrin underwent demetalation under the influence of concentrated sulfuric acid to produce free-base porphyrin which on zinc metal insertion using zinc acetate in a chloroform-methanol mixture afforded coumarin-fused zinc(ii) pyrido[2,3-b]porphyrin in good yield.