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Volumn 69, Issue 12, 2004, Pages 4108-4115

Photochemistry of fluorinated heterocyclic compounds. An expedient route for the synthesis of fluorinated 1,3,4-oxadiazoles and 1,2,4-triazoles

Author keywords

[No Author keywords available]

Indexed keywords

AMINES; AMMONIA; ISOMERIZATION; PHOTOCHEMICAL REACTIONS; SYNTHESIS (CHEMICAL); X RAY ANALYSIS;

EID: 2942588783     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo049814e     Document Type: Article
Times cited : (46)

References (68)
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    • (g) Chemistry of Organic Fluorine Compounds II. A Critical Review; Hudlicky, M., Pavlath, A. E., Eds.; ACS Monograph 187; American Chemical Society: Washington, DC, 1995.
    • (1995) Chemistry of Organic Fluorine Compounds II. A Critical Review
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    • Attanasi, O. A., Spinelli, D., Eds.; Societa Chimica Italiana: Roma
    • (d) Furin, G. G. Targets in Heterocyclic Systems; Attanasi, O. A., Spinelli, D., Eds.; Societa Chimica Italiana: Roma, 1998; Vol. 2, pp 355-441.
    • (1998) Targets in Heterocyclic Systems , vol.2 , pp. 355-441
    • Furin, G.G.1
  • 21
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    • de Mayo, P., Ed.; Academic Press: New York
    • For photoinduced rearrangements of five-membered heterocycles, see: (a) Padwa, A. In Rearrangements in Ground and Excited States; de Mayo, P., Ed.; Academic Press: New York, 1980; Vol. III, pp 501-547.
    • (1980) Rearrangements in Ground and Excited States , vol.3 , pp. 501-547
    • Padwa, A.1
  • 23
    • 0001640232 scopus 로고    scopus 로고
    • Attanasi, O. A., Spinelli, D., Eds.; Società Chimica Italiana: Roma
    • (c) D'Auria, M. In Targets in Heterocyclic Systems; Attanasi, O. A., Spinelli, D., Eds.; Società Chimica Italiana: Roma, 1999; Vol. 2, pp 233-279.
    • (1999) Targets in Heterocyclic Systems , vol.2 , pp. 233-279
    • D'Auria, M.1
  • 30
    • 2942615575 scopus 로고    scopus 로고
    • note
    • These ANRORC-like rearrangements appear determined by the presence of the perfluoroalkyl group at C-5 of the oxadiazole.9 The Addition of the Nucleophile on the C-5 is followed by Ring Opening and then Ring Closure by attack of the β nucleophilic center of the bidentate reagent (hydrazine or hydroxylamine) at the C-3 of the initial oxadiazole ring, a molecule of hydroxylamine being displaced in the final step.
  • 31
    • 0000728360 scopus 로고
    • and references therein
    • (a) Vivona, N.; Buscemi, S. Heterocycles 1995, 41, 2095-2116 and references therein.
    • (1995) Heterocycles , vol.41 , pp. 2095-2116
    • Vivona, N.1    Buscemi, S.2
  • 34
    • 0029994183 scopus 로고    scopus 로고
    • For photoinduced rearrangements involving the 1,2,4-oxadiazole heterocycle, see also: (a) Buscemi, S.; Vivona, N.; Caronna, T. J. Org. Chem. 1996, 61, 8397-8401.
    • (1996) J. Org. Chem. , vol.61 , pp. 8397-8401
    • Buscemi, S.1    Vivona, N.2    Caronna, T.3
  • 44
    • 2942524229 scopus 로고    scopus 로고
    • note
    • As previously observed,15c,16,17 the presence of an XH moiety at C-3 of the 1,2,4-oxadiazole heterocycle is needed for the ring photo. isomerization to occurr, and this is valid for both fluorinated and nonfluorinated substrates. Therefore, in the presence of a base, the involvement of deprotonated species from 3-N-methylaminooxadiazoles 9 in the reaction pathway cannot be excluded. In this context, it is worthy to note that the NH moiety of the starting oxadiazole is expected to show a significant acidity in the excited state and could be efficiently deprotonated.
  • 47
    • 2942615576 scopus 로고    scopus 로고
    • note
    • In an independent experiment, aminolysis on representative 3-methoxy-triazole 22a in the presence of methylamine left the starting material unchanged, thus excluding that compounds 11-15 could be formed by an aminolysis reaction of the first formed compounds 22 with the employed amines.
  • 48
    • 2942535048 scopus 로고    scopus 로고
    • note
    • For the open-chain compound 23, one could anticipate different tautomeric hydrogen-bonded structure or ring-chain equilibria. However, this structural aspect has not been developed in this study.
  • 49
    • 2942624582 scopus 로고    scopus 로고
    • note
    • This observation explains low yields of 3-amino- (or 3-N-alkylamino-)1,2,4-oxadiazoles obtained in the irradiation of 3-perfluoroalkanoylamino furazans in the presence of ammonia or aliphatic primary amines (see Scheme 1).6


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.