Microwave-assisted Synthesis of 2-Substituted-2-Thiazolines and 5,6-Dihydro-4H-1,3-thiazines

MARÍA C. MOLLO; JUAN A. BISCEGLIA; NATALIA B. KILIMCILER; MICHELE MANCINELLI; LILIANA R. ORELLI

SYNTHESIS-STUTTGART

GEORG THIEME VERLAG KG

Año: 2020 vol. 52 p. 1666 - 1679

0039-7881

An efficient and general method for the synthesis of 2-substituted thiazolines and 5,6-dihydro-4H-1,3-thiazines was developed, by microwave-assisted ring closure of omega-thioamidoalcohols promoted by ethyl polyphosphate (PPE). The cyclization reaction involves an SN2-type mechanism and features the advantages of very short reaction times, high yields and predictable stereochemical outcome. The acyclic precursors were prepared in high overall yields by an improved diacylation-thionation-saponification sequence from commercially available omega-aminoalcohols. The whole procedure is metal free and operationally easy.