Tandem Protocol for the Synthesis of Pyrano[3,2-c]quinolone Derivatives Using Taurine as a Green Bio-Organic Catalyst in Aqueous Medium.

A series of pyrano[3,2-c]quinolone derivatives has been synthesized in the presence of taurine (2-aminoethanesulfonic acid) as a green bio-organic catalyst and water as the solvent. The target compounds were synthesized through the three-component reaction between aldehydes, malononitrile/ethylcyanoacetate, and 4-hydroxy-1-methyl-2(1H)-quinolone. The advantages of this protocol are excellent yields of products, short reaction times, cost efficiency, atom economy, and a simple work-up procedure with no need for extra purification techniques. Moreover, the catalyst can be easily recovered and reused for up to three cycles without losing any significant activity.

Synthesis and antitubercular screening of some novel 4H-1,4- benzothiazines and their sulfones under environment benign solvent free conditions as future anti-tubercular agents.

Some novel analogs of 4H-1,4-benzothiazines were synthesized under environmentally benign solvent free conditions by one pot oxidative cyclocondensation of substituted 2- aminobenzenthiols with compounds having active methylene group and then converted in to sulfones. These compounds were examined as antitubercular agents against Mycobacterium tuberculosis H37Rv using REMA plate method. The best results have MICs from 6.4 to 8.8 µg/mL, comparable to phenothiazines. IR, NMR and mass spectral investigations are included for structural elucidation.