Transannular anti-Michael addition: formation of 4H-pyrazolo[5,1-c]thiazines

Yat Fan Suen, Håkon Hope, Michael H. Nantz, Makhluf J. Haddadin, Mark J. Kurth

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The reaction of 2-(diphenylmethylene)thietan-3-one (2) with 1,2,4,5-tetrazines (3a-c) in KOH/MeOH/THF gives 4H-pyrazolo[5,1-c]thiazines (7a-c). This novel condensation reaction proceeds via the intermediacy of an 8-(diphenylmethylene)-2H-1,4,5-thiadiazocin-7(8H)-one (5), which undergoes a multi-step rearrangement including a rare anti-Michael addition.

Original languageEnglish (US)
Pages (from-to)7893-7896
Number of pages4
JournalTetrahedron Letters
Issue number45
StatePublished - Nov 6 2006


  • 4H-Pyrazolo[5,1-c]thiazine
  • Anti-Michael addition
  • Pyrazole

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Drug Discovery


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