59574-50-4Relevant academic research and scientific papers
Cycloaddition-Elimination Reactions of 4-Methyl-5-(substituted)-imino-Δ2-1,2,3,4-thiatriazolines with Isocyanates
L'abbe, Gerrit,Weyns, Nancy,Sannen, Ingrid,Delbeke, Pieter,Toppet, Suzanne
, p. 405 - 409 (2007/10/02)
4-Methyl-5-(substituted)imino-1,2,3,4-thiatriazolines 1 (R2 Me) undergo cycloaddition-elimination reactions with isocyanates to yield 4-methyl-5-(substituted)imino-1,2,4-thiadiazolidine-3-ones 5 via the thermodynamically less stable isomers 4.The latter have not been isolated, except for 4q which was shown to isomerize rapidly into 5q with phenylsulfonyl isocyanate.The reactions of 1 are accelerated by using less bulky R2 substituents and more electrophilic isocyanates, in accordance with the viewpoint that 1 reacts as a masked 1,3-dipole.The products 4i-n (= 5i-n), derived from 1b, add isocyanates reversibly to give 2,3,4,5-tetrahydro-6aλ4-thia-1,3,4,6-tetraazapentalene-2,5-diones 9i-n, which have been isolated and characterized spectroscopically.Such compounds with a hypervalent sulfur atom thus occur as intermediates during the isomerization of 4 to 5 under the influence of isocyanates.
