A convenient synthesis of trifluoromethylipyridazines from 3-hydrazono-1,1,1-trifluoroalkan-2-ones

Heterocycles

Volumn 63, Issue 3, 2004, Pages 707-713

  Kamitori, Yasuhiro ^a   Sekiyama, Tomoko ^a  

^a KOBE UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

4 ACETYL 3 METHYL 5 TRIFLUOROMETHYLPYRIDAZINE; ACETIC ACID ETHYL ESTER; ACETYLACETONE; ALKANONE; HYDRAZONE DERIVATIVE; KETONE DERIVATIVE; PYRIDAZINE DERIVATIVE; TRIFLUOROMETHYLPYRIDAZINE DERIVATIVE; UNCLASSIFIED DRUG;

ARTICLE; CHEMICAL REACTION; CHEMICAL STRUCTURE; ELECTRON TRANSPORT; REACTION ANALYSIS; STRUCTURE ANALYSIS; SYNTHESIS;

EID: 1342331984     PISSN: 03855414     EISSN: None     Source Type: Journal    
DOI: 10.3987/COM-03-9975     Document Type: Article

References (19)

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12. Y. Kamitori, Heterocycles, 2000, 53, 107.
13. 2NN=CHR) because of exclusive trifluoroacetylation at terminal nitrogen. Therefore it was necessary to prepare 2 from aldehyde dialkylhydrazones via diketone (1).
14. Y. Kamitori, M. Hojo, and T. Yoshioka, Heterocycles, 1998, 48, 2221.
15. E. Breitmaier and E. bayer, Angew Chem., 1969, 81, 785.
16. -1 lower than that of 2a reveals that 6a is (3-methyl-6-p-tolyl-5-trifluoromethylpyridazin-4-yl)phenylmethanone and not 1-(3-phenyl-6-p-tolyl-5-trifluoromethylpyridazin-4-yl)ethanone.
17. On the basis of the density functional calculation (pBP/DN** ), the activation energy for [4+2] cycloaddition of 2 (R=Ph) with enolized acetylacetone (Scheme 3) was estimated as 32 Kcal/mol. Calculations were accomplished using the computer program package PC SPARTAN pro (Wavefunction, Inc). About pBP/DN**, see: A. D. Becke, Phys. Rev. A, 1988, 38, 3089; J. P. Perdew, Phys. Rev. B, 1986, 33, 8822.
18. On the basis of the density functional calculation (pBP/DN** ), the activation energy for [4+2] cycloaddition of 2 (R=Ph) with enolized acetylacetone (Scheme 3) was estimated as 32 Kcal/mol. Calculations were accomplished using the computer program package PC SPARTAN pro (Wavefunction, Inc). About pBP/DN**, see: A. D. Becke, Phys. Rev. A, 1988, 38, 3089; J. P. Perdew, Phys. Rev. B, 1986, 33, 8822.
19. Our calculations predict that inverse demand type hetero Dield-Alder reaction should occur between 2 (R=Ph) and acetylacetone enol. Optimized orbital fitting of HOMO of acetylacetone enol with LUMO of 2 suggests the regiochemistry of the transition state structure shown in Scheme 3.