The title compound, C(20)H(16)N(2)O, has two molecules in the asymmetric unit and the crystal structure shows that the central pyridine ring of each molecule has a flat boat conformation. The terminal C atom in one of the molecules is disordered over two positions, with relative occupancies of 0.594 (14) and 0.398 (14). Intermolecular C-H.N and C-H.pi interactions and pi-pi stacking, along with intramolecular C-H.N and C-H.pi interactions, help to stabilize the structure.

A number of 2‐thioxopyrido[3′,2′:4,5]thieno[3,2‐H]pyrimdin‐4(3H‐ones (5) have been synthesized by cyclocondensation of 2‐carbethoxy‐3‐amino‐4‐phenyl‐6‐substituted‐thieno[2,3‐b]pyridines (3) with various isothiocyanates. Compounds 5 were S‐methylated routinely and the reactions compared under solid‐liquid phase transfer conditions to obtain 2‐methylthiopyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidin‐4(3H)‐ones (6). The new triheterocyclic pyridothienopyrimidines were prepared with the objective to study their pharmacological properties.

An efficient and novel strategy has been developed using liquid liquid phase transfer catalysis conditions for the synthesis of 2-amino-4,6-diarylnicotinonitrile and 5,7-diaryltetrazolo[1,5-a]pyridine-8-carbonitrile. The former was obtained either by two step process involving azidolysis of 2-chloro-4,6-diarylnicotinonitrile followed by chemoselective reduction of tetrazole moiety while facile one-pot procedure was conveniently carried out from corresponding 2-chloro-4,6-diarylnicotinonitrile.

Key indicatorsSingle-crystal X-ray study T = 293 K Mean (C-C) = 0.005 Å R factor = 0.078 wR factor = 0.166 Data-to-parameter ratio = 12.8For details of how these key indicators were automatically derived from the article, see

1 was reacted with ethyl 2-mercaptoacetate 2 to furnish ethyl 2-(3-cyano-4,6-diarylpyridin-2-ylthio)acetate 3 as intermediates. These intermediates were cyclized by Thorpe-Zeigler cyclization using solid-liquid phase-transfer catalysis conditions to give ethyl 3-amino-4,6-diarylthieno[2,3-b]pyridine-2-carboxylate 4. One-pot heterocyclization without isolating the intermediates was also achieved using solid-liquid phase transfer conditions.