The synthesis of a new family of phenylselanyl substituted pyrano[3,2-c] chromenes is presented. The cyclocondensation reaction of 3-formylchromones 1 with phenylselanylacetic acid 2 in acetic anhydride under mild conditions gave the novel 3-(phenylselanyl)-2-oxo-2H,5H-pyrano[3,2-c]chromen-5-yl acetates P1 in 80% yield. Further treatment of acetates P1 with ethanolic or aqueous medium led to the corresponding 5-ethyloxy-3-(phenylselanyl)-2-oxo-2H,5H-pyrano[3,2-c]chromen P3 and 3-(phenylselanyl)-2H,5H-pyrano[3,2-c]chromen-5-ol P4 , respectively. We found the reaction of phenylselanylacetic acid with arylcarbaldehydes in acetanhydride at room temperature yielded the corresponding 2-(phenylselanyl)cinnamoyl acid P5. This reaction at elevated temperature, under reflux or in the solventless mixture at 180oC led only to the diphenyl-diselane P6 and a pitch polymer.

The solid-state reaction between anilines and phenacyl bromides in the presence of an equimolecular amount of sodium bicarbonate gives phenacylanilines. Microwave irradiation of mixtures of these compounds with anilinium bromides at 560 W for 45-60 s provides a general, solvent-free method for the synthesis of 2-arylindoles in 50-56% overall yields. A one-pot variation of the method, involving irradiation of 2:1 mixtures of anilines and phenacyl bromides, allowed a simplified experimental procedure and led to improved yields (52-75%).

The microwave-assisted ring closure of 2-benzoxazolylguanidines (1a-c), 2-benzothiazolylguanidines (3a-c) and 2-benzimidazolylguanidine (5) using phenyl isocyanate as a carbonylating reagent afforded 2-amino-4-oxo-[1,3,5]triazino[2,1-b][1,3]benzoxazoles (2a-c), 2-amino-4-oxo-[1,3,5]triazino[2,1-b][1,3]benzothiazole (4a-c) and 2-amino-4-oxo-3H-[1,3,5]triazino[1,2-a]benzimidazole (6), respectively. The tautomerism in the prepared compounds was investigated. Compounds 2a-c and 4a-c were found to exist in DMSO solution as 2-imino-4-oxo- tautomers. 2-Amino-4-oxo-3H- and 2-amino-4-hydroxy- forms of 6 predominated in tautomeric equilibrium at the same condition.

The improved synthesis of 2,4-dimethyl-8-[2'-(2H-tetrazol-5-yl)-biphenyl-4-ylmethyl]-5,8-dihydro-6H-pyrido[2,3-d] pyrimidin-7-one (tasosartan-1, click for 3D-structure) on multigramscale is described. The synthesis was developed in context of the DrugMatrix-genomics project.