Novel tandem hydration/cyclodehydration of alpha-thiocyanatoketones to 2-oxo-3-thiazolines. Application to thiazolo[5,4-c]quinoline-2,4(3aH,5H)-dione synthesis

Antonín Klásek; Vladimír Mrkvicka; Andrej Pevec; Janez Kosmrlj

doi:10.1021/jo0493370

Novel tandem hydration/cyclodehydration of alpha-thiocyanatoketones to 2-oxo-3-thiazolines. Application to thiazolo[5,4-c]quinoline-2,4(3aH,5H)-dione synthesis

J Org Chem. 2004 Aug 20;69(17):5646-51. doi: 10.1021/jo0493370.

Authors

Antonín Klásek¹, Vladimír Mrkvicka, Andrej Pevec, Janez Kosmrlj

Affiliation

¹ Department of Food Engineering and Chemistry, Faculty of Technology, Tomas Bata University, CZ-762 72 Zlín, Czech Republic. klasek@ft.utb.cz

PMID: 15307735
DOI: 10.1021/jo0493370

Abstract

Novel tandem hydration of alpha-thiocyanatoketones to thiocarbamates followed by in situ cyclodehydration to fused 2-oxo-3-thiazolines is described. The reaction is applied to the synthesis of [1,3]thiazolo[5,4-c]quinoline-2,4(3aH,5H)-diones (4). Concentrated sulfuric acid was found to be critical for the reaction as both corresponding 2,3-dioxo-1,2,3,4-tetrahydroquinolin-3-yl thiocyanates (2) and S-(2,4-dioxo-1,2,3,4-tetrahydroquinolin-3-yl) thiocarbamates (3) rapidly hydrolyze in the presence of water to 4-hydroxyquinolin-2(1H)-ones (1).