N. Nedolya, Nataly I. Schlyakhtina, L. V. Klyba
Dec 23, 2002
Citations
0
Influential Citations
25
Citations
Journal
Tetrahedron Letters
Abstract
Abstract Reaction of lithiated methoxyallene, 1-ethoxyethoxyallene, 1-(methylthio)propyne and 2-butyne with methoxymethyl isothiocyanate, MeOCH 2 NCS followed by methylation affords the imidothioates H 2 CCC(R)C(SMe)NCH 2 OMe [R=Me, OMe, OCH(Me)OEt, SMe]. Rearrangement to the fully conjugated systems H 2 CCHC(R)C(SMe)NCHOMe and subsequent electrocyclisation of these compounds leads to the 5-substituted 6-(methylthio)-2-methoxy-2,3-dihydropyridines with good to excellent yields. In the presence of acidic catalysts or by heating at elevated temperatures these dihydropyridines eliminate methanol to afford 3-substituted 2-(methylthio)pyridines. The aroma compound 2-(methylthio)-3-pyridinol was obtained by acid-catalysed treatment of 3-(1-ethoxyethoxy)-2-(methylthio)pyridine.