Fluorinated Ketene Dithioacetals. Part 10. Synthesis of New Perfluorinated (2H)-Pyridazin-3-ones and 3-(Alkyl- or Arylamino) Substituted Pyridazines

Abstract

α-Trifluoromethyl γ-keto thiolesters 4a and 7, obtained from the corresponding perfluoroketene dithioacetals 3a, led in a two-step sequence (condensation with hydrazine - dehydrogenation reaction) to the (2H)-pyridazin-3-ones 9a,c-e. Subsequent chlorination and substitution with amines led to 3-(alkyl- or arylamino)-4-trifluoromethyl pyridazines 11a-d. The higher homologue, the α-pentafluoroethyl γ-keto thiolester 4b, reacted similarly, but a subsequent HF elimination allowed direct access to 4-tetrafluoroethyl pyridazin-3-ones 13b,c.

Key words

fluorine - nitrogen heterocycles - pyridazine - (2H)-pyr­idazin-3-one

References

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12

Compound 4b was prepared according to the same procedure described for γ-keto thiolesters 4a, see ref. 7.