Chitosan-SO3H: an efficient,biodegradable, and recyclable solid acid for the synthesis of quinoline derivatives via Friedländer annulation

Chitosan-SO₃H is found to catalyze the Friedländer condensation/annulation reaction of 2-aminoaryl ketones with α-methyleneketones to produce the corresponding quinoline derivatives in high yields in short reaction times. The use of recyclable and biodegradable chitosan-SO₃H makes this method quite simple, more convenient, and economically viable compared to acid catalyzed methods reported in the literature.     

Total synthesis of (+)-varitriol via a symmetrical furanose diol as the key intermediate

Alternative, simple and efficient route for (+)-varitriol (1), a marine-derived natural product with potent biological activity, has been synthesized from d-ribose. In this synthetic strategy symmetrical diol (6) with mono alcohol protection, the key intermediate, was produced in eight steps with 35% overall yield and the significance of 6 as the key furanoside building block for the synthesis of novel analogues of 1 for SAR studies was explained.