344866-00-8Relevant academic research and scientific papers
Composes sulfures heterocycliques. XCVIII. Reaction d'ynamines sur des derives du dithiole-1,3
Dibo, Ahamada,Stavaux, Madeleine,Lozac'H, Noel
, p. 277 - 280 (2007/10/02)
1,3-Dithiol-2-ones 1 and 1,3-dithiole-2-thiones 2 react with ynamines 3, yielding respectively N,N-diethyl-α-(1,3-dithiol-2-ylidene) amides 4 and thioamides 5, via 2 + 2 cycloaddition followed by ring opening. 1H nmr showed compounds 4 and 5 to be mixtures of Z and E isomers and the signals related to the diethylamino group support a bicyclic structure 5y. Compounds 5 can be obtained by reacting phosphorus pentasulfide with the corresponding compounds 4 or by reacting an alkyne with a 5-diethylamino-1,2-dithiole-3-thione.Isomerization of 5 into a 1,6,6aλ4-trithiapentalene 6 is difficult and has only been performed in low yields by long heating with thioacetamide in boiling naphthalene. 2-Methylthio-1,3-dithiolylium iodides also react with ynamines giving an ionic intermediate which yields a compound 5 by reaction with a nucleophile: sodium hydrogensulfide or pyridine.All reaction observed between ynamines and 1,3-dithiole derivatives take place via a 2 + 2 cycloaddition mechanism involving carbon 2 of the ring and the substituent (O, S or SCH3) on this atom but leaving the 1,3-dithiole ring untouched.
