Fahimeh Sadat Hosseini

A simple synthesis of new series of functionalized chromene derivatives through an efficient, one‐pot, multicomponent reaction of nitroketene N,S‐acetals, salicylaldehydes, and cyanoacetohydrazide in ethanol at ambient temperature in good to high yields is reported. This novel efficient method has the advantages of mild reaction conditions, absence of catalyst, simple work‐up, and the non‐chromatographic purification of products.

One-pot synthesis of C₂-symmetric chromene derivatives, which serve as building blocks to prepare liquid crystals with potential electrical or optical properties.

The reaction between ketene animal/ketene N,S-acetals (derived from diamines/cysteamine hydrochloride and 1,1-bis(methylthio)-2-nitroethene) with aromatic aldehydes, and Meldrum's acid led to the title compounds. The reaction conditions were optimized using response surface methodology (RSM). The two independent variables (temperature and water content of aqueous ethanol), and the responses (yield of product and reaction time) were studied. The range of each parameter selected was: T = 25–100 °C and water = 0–100%. The optimal values were: T = 72 °C and water = 33%. This work offers significant advantages including use of a green solvent, experimental simplicity, absence of catalyst, a simple work-up and purification process, moderate to good yields, and preparation of potentially bioactive compounds.

A fast and convenient protocol for the synthesis of a new class of piperidin-1-ium 6-amino-4-aryl-3,5-dicyano-1,4-dihydropyridine-2-thiolate (piperidinium salt) derivatives is developed by the one-pot, three-component reactions of cyanothioacetamide, aromatic aldehydes and piperidine in dichloromethane at room temperature. The features such as operational simplicity, mild conditions, absence of catalyst, high yields in short reaction times, simple purification process with no chromatographic technique make the protocol highly attractive. GRAPHICAL ABSTRACT

An easy, efficient, and environmentally benign synthesis of new class of thiazolopyridine carboxamide derivatives is reported via one-pot, multi-component reaction of 2-(nitromethylene)thiazolidine derived from the addition of cysteamine hydrochloride to nitro ketene dithioacetal with aromatic aldehydes and cyanoacetamide using catalytic amount of triethylamine (Et₃N) in ethanol/water at reflux in good to excellent yields. GRAPHICAL ABSTRACT