A facile four-component Gewald reaction under organocatalyzed aqueous conditions

Abstract

In the presence of water and triethylamine, a four-component process involving ethyl cyanoacetate, an α-methylene carbonyl compound, a primary or a secondary amine, and elemental sulfur leads to efficient room-temperature formation of 2-amino-3-carboxamide derivatives of thiophene in short time periods. The products, which precipitate from the reaction mixtures, are easily obtained by simple filtration and recrystallization from ethyl acetate/hexanes.

Synthesis of (1,4-benzoxazinones-3-yl)malonate derivatives via cross-dehydrogenative-coupling reactions under ball-milling conditions

“…22,23 These features make various types of iron catalysts very popular in organic synthesis and have resulted in many applications in recent decades. In continuation of our investigations in heterocyclic chemistry, 25,26 we recently reported a ballmilled/Fe(II)-catalyzed CDC of 1,4-benzoxazinones with indoles. 27 Now, we would like to report a convenient method for ball milling coupling of 1,4-benzoxazinones with malonate esters using FeCl2.2H2O as the catalyst of the process, as shown in Scheme 1 for the coupling of derivatives of 1 with 2 using the oxidant, DDQ.…”