Abstract
Abstract This study treats the reactions of methylthio-, ethylthio-, or benzylthiodiphenylcyclopropenium ion (1) with 5-, 6-, and 7-membered cyclic 1,3-diketones, giving either 2-alkylthio-2H-pyrans or dienone derivarives. Treatment of 1 with 1,3-cyclopentanedione, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 4-hydroxy-6-methyl-2-pyrone, 4-hydroxycoumarin, and 1,3-cycloheptanedione in the presence of triethylamine afforded 2-alkylthio-2H-pyrans. The structure of the products was elucidated on the basis of their elemental analyses, IR, 1H-NMR, 13C-NMR, and mass spectroscopic data, as well as chemical transformations. 2-Alkylthio-2H-pyrans with mercury(II) chloride in an alcohol underwent conversion to the corresponding 2-alkoxy-2H-pyrans. The 1H- and 13C-NMR data of these compounds clearly show that the equilibrium lies completely on the side of the 2H-pyran. In contrast, the reaction of 1 with 1,3-indandione yielded the ring-opened dienone derivative as a mixture of E and Z isomers.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
