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Short Paper | Regular issue | Vol 89, No. 9, 2014, pp.2168-2176
Published online, 6th August, 2014
DOI: 10.3987/COM-14-13058
A Simple Synthesis of 4-Hydroxy-3,4-dihydropyrido[3,4-d]pyrimidine-2(1H)-thione Derivatives by the Reaction of 3-Isothiocyanatopyridin-4-yl Ketones with Primary Amines

Kazuhiro Kobayashi,* Hiroki Inouchi, and Manami Konishi

*Division of Applied Chemistry, Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan

Abstract

The reaction of aryl(3-isothiocyanatopyridin-4-yl)methanones, prepared easily from commercially available 3-aminopyridine, with primary amines at room temperature afforded 3-substituted 4-aryl-4-hydroxy-3,4-dihydropyrido[3,4-d]pyrimidine-2(1H)-thiones in good yields. These ketones could be converted to new tricyclic heterocyclic systems, 2,3-dihydro-5H-pyrido[3,4-d]thiazolo[3,2-a]pyrimidine and 3,4-dihydro-2H,6H-pyrido[3’,4’:4,5]pyrimido[2,1-b][1,3]thiazine, upon treatment with 2-bromoethanamine hydrobromide and 3-bromopropaneamine hydrobromide, respectively, in the presence two equivalents of triethylamine.