Mannich condensations of activated cyclic enamines

Octahydropyrimido[4,5-g]quinazoline-5,10-diones: their multicomponent synthesis, self-assembly on graphite and electrochemistry

A green multicomponent synthesis of previously unreported octahydropyrimido[4,5-g]quinazoline-5,6-diones was developed from simple building blocks. These highly symmetrical compounds show strong propensity to self-assembled molecular network (SAMN) formation on highly oriented pyrolytic graphite. The SAMN type is easily tunable by changing molecular characteristics. The redox behavior was studied by cyclic voltammetery.

2-Amino-4,5-dihydrothiophene-3-carbonitriles: A New Synthesis, Quantum Chemical Studies, and Mannich-Type Reactions Leading to New Hexahydrothieno[2,3-d]pyrimidines

trans-2-Amino-4-aryl-5-benzoyl-4,5-dihydrothiophene-3-carbonitriles were prepared either by the reaction of 3-aryl-2-cyanothioacrylamides with α-thiocyanatoacetophenone or by the Michael-type addition of cyanothioacetamide to α-bromochalcones followed by intramolecular cyclization. The mechanism of the first reaction was studied using high-level quantum chemical calculations. Density functional theory (DFT) studies were carried out to determine the mechanism of the first reaction. A new approach toward the construction of the thieno[2,3-d]pyrimidine core system was demonstrated by the reaction of the prepared dihydrothiophenes with HCHO and RNH2 under noncatalyzed Mannich conditions.