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

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

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 is developed via microwave-assisted ring closure of 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 a predictable stereochemical outcome. The acyclic precursors are prepared in high overall yields by an improved diacylation? thionation?saponification sequence from commercially available -aminoalcohols. The whole process is metal-free and operationally simple.