Generation and selected reactions of chlorinated thiocarbonyl S-imides^*

* Dedicated to Professor Heinz Heimgartner on the occasion of his 75th birthday.

ABSTRACT

N-Aryl-1,1,1-trichloromethanesulfenamides ArNH-SCCl₃ easily undergo dehydrochlorination upon treatment with potassium hydroxide in ethanolic solution. The intermediate thiocarbonyl S-imides formed thereby behave differently depending on the type of the N-aryl group. The sterically crowded N-(2,6-dimethylphenyl)- and -N-(2,4,6-trimethylphenyl)-1,1,1-trichloromethanesulfenamides yield the corresponding sulfur N,N′-diaryldiimides via a multi-step reaction, whereas the less crowded 2-methylphenyl and 4-methylphenyl derivatives undergo a regioselective ‘head-to-head’ dimerization leading to 5,5,6,6-tetrachloro-1,4,2,3-dithiadiazinanes in high yields. An identical reaction course is observed in the case of the 4-methoxy- and 4-bromoaniline derivatives. A diradical mechanism is postulated to explain the ‘head-to-head’ dimerization pathway.

GRAPHICAL ABSTRACT

KEYWORDS:

• Thiocarbonyl compounds
• reactive intermediates
• thiocarbonyl S-imides
• chlorinated organic compounds
• head-to-head dimerization

Acknowledgements

Prof. U. Behrens, Univ. Hamburg, Germany, is acknowledged for advice and support (X-ray structures). Skillful performance of microanalyses by Ms Hanna Jatczak and Ms Agnieszka Cieślińska (University of Łódź) is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

* Dedicated to Professor Heinz Heimgartner on the occasion of his 75th birthday.

Additional information

Funding

G. M. and P. P. thank the National Science Center (Cracow, Poland) for generous financial support (Grant Maestro-3 (Dec-2012/06/A/ST5/00219). A. S. thanks the Kemisk Forenings Rejsefond (Danish Chemical Society’s Travel Fund) for a travel grant.