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Volumn 52, Issue 2, 2011, Pages 341-345

Stereochemistry and reactivity of F- and H-vinyldiazocarbonyl compounds and their phosphazines: Synthesis of pyrazoles and pyridazines

Author keywords

1,5 Electrocyclizations; 2 Vinyl 2 diazocarbonyl compounds; Cis trans Stereochemistry; Diaza Wittig reactions; Phosphazines; Pyrazoles; Pyridazines

Indexed keywords

CARBONYL DERIVATIVE; PYRAZOLE DERIVATIVE; PYRIDAZINE DERIVATIVE; VINYL DERIVATIVE;

EID: 78650017488     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2010.11.073     Document Type: Article
Times cited : (31)

References (42)
  • 19
    • 78649997987 scopus 로고    scopus 로고
    • 9 but to the best of our knowledge, detailed investigations with these carbonyl substrates have not been carried out
    • 9 but to the best of our knowledge, detailed investigations with these carbonyl substrates have not been carried out.
  • 21
    • 78650017280 scopus 로고    scopus 로고
    • note
    • 11) reaction of Wittig reagent 7 with acetoacetic ester H-1b and acetylacetone H-1c occurred with very low efficacy (5-28%). After a series of screening experiments the yields of non-fluorinated 2-vinylcarbonyl compounds H-2b,c were increased to 63% (reflux in benzene for 20 h) and 38% (reflux in acetonitrile for 20 h).
  • 27
    • 78650026693 scopus 로고    scopus 로고
    • note
    • 13C NMR spectra of vinyl acetates H-2b and F-2d only the signals of the alkoxycarbonyl carbons were present at 170.7 and 170.3 (two isomers of H-2b) and at 168.9 ppm (for F-2d). In the case of vinylketones H-2c and F-2e only the signals of the carbon atoms of the acetyl carbonyl groups were observed (204.7, 204.6, 198.4, 198.2 ppm, associated with four isomers of H-2c) and at 197.8 and 201.0 ppm (related to two isomers of F-2e).
  • 28
    • 78650010134 scopus 로고    scopus 로고
    • note
    • Two stereoisomers of vinyl acetate H-2b were formed by the Wittig process, while fluorinated analog F-1d gave only one isomer F-2d. Reaction with acetylacetone -1c gave rise to both regioisomers of vinyl ketone -2c, and each was represented in the reaction mixture by 2 stereoisomers (altogether 4 isomers in the ratio ∼ 2:1:7:2 from the signals due to the 2- protons at 6.24, 6.14, 5.85, 5.73 ppm), whereas the fluorinated analog of acetylacetone F-1e provided a mixture of two isomers of vinyl ketones F-2e (1:1).
  • 33
    • 78649983275 scopus 로고    scopus 로고
    • note
    • 2O, 12 h).
  • 36
    • 78649982692 scopus 로고    scopus 로고
    • note
    • 25 All hydrogen atoms were calculated and refined in riding modus. CCDC 788803 for H-3a and CCDC 788804 for H-5b contain the supplementary crystallographic data. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data-request/cif from the Cambridge Crystallographic Data Centre.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.