Mass spectra of novel groups of functionalized hetrocycles: II. Synthesis and mass spectra of 2-(alkyl[2-propenyl, 2-propynyl]thio)-1H-pyrroles

An original synthetic approach to 2-(alkyl[2-propenyl-, 2-propynyl]thio)- 1 H-pyrroles was proposed, involving deprotonation of allyl isothiocyanate wi th the complex super base KN(i-Pr)(2)-t-BuOLi, cyclization of the resulting carbanion to a pyrrole-2-thiol dianion and subsequent alkylation of the la tter. Major pathways of electron-impact fragmentation of the synthesized py rroles were revealed. The [M - Alk](+) ions were found to isomerize into a common 1,3-thiazine structure. The fragmentation of 2-(2-propenylthio)- and 2-(2-propynylthio)-1H-pyrroles mainly occurs via isomeric bicyclic structu res.