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Volumn 54, Issue 42, 1998, Pages 12745-12774

Total synthesis of the antifungal dilactones UK-2A and UK-3A: The determination of their relative and absolute configurations, analog synthesis and antifungal activities

Author keywords

Antifungals; Asymmetric synthesis; Medium ring heterocycles; Mitsunobu reactions

Indexed keywords

ANTIFUNGAL AGENT; CITRININ; LACTONE DERIVATIVE; UK 2A; UK 3A; UNCLASSIFIED DRUG;

EID: 0032532259     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4020(98)00777-7     Document Type: Article
Times cited : (31)

References (46)
  • 3
    • 85038546551 scopus 로고
    • New approaches for antifungal drugs. Boston: Birkhäuser
    • 3. Fernandes, P. B., Editor. New approaches for antifungal drugs. Boston: Birkhäuser, 1992, 1.
    • (1992) , pp. 1
    • Fernandes, P.B.1
  • 8
    • 85038540203 scopus 로고    scopus 로고
    • note
    • 5b
  • 21
    • 85038540771 scopus 로고    scopus 로고
    • note
    • 14. All new compounds except volatile compounds were spectroscopically characterized and furnished satisfactory elemental analyses (C, H, N, ± 0.3%) or high-resolution mass spectra. See in the experimental section.
  • 25
    • 85038552204 scopus 로고    scopus 로고
    • note
    • 34 was also examined, but the yield was poor because of the by-product formations.
  • 36
    • 85038551927 scopus 로고    scopus 로고
    • note
    • 25. 4-lodo-3-methoxymethoxypyridine was also prepared with 1,2-diiodo-1,1,2,2-tetrafluoroethane, but the next methoxy replacement was not as good as the case of 4-bromo-3-methoxymethoxypyridine because of the reductive deiodination by-reaction resulting in 3-methoxymethoxypyridine. It should also be noted that 4-bromo-3-methoxymethoxypyridine was much faster to react to NaOMe than 4-iodo-3-methoxymethoxypyridine, although the reason still remains unclear.
  • 37
    • 85038551785 scopus 로고    scopus 로고
    • note
    • 26. Structure of UK-2A is depicted with the absolute stereochemistry found in our synthetic UK-2A.
  • 38
    • 85038554250 scopus 로고    scopus 로고
    • note
    • 1H NMR of the synthesized γ-lactone 24 was different from the reported one. The coupling pattern of each signal in our γ-lactone 24 was very similar to the reported γ-lactone 24, however, the chemical shifts of some signals were not in accordance with those of the corresponding signals of the reported γ-lactone 24. Since γ-lactone 25 synthesized in our hands was identical with the reported γ-lactone 25, our γ-lactone 24 should be identical with the reported γ-lactone 24.
  • 39
    • 85038549799 scopus 로고    scopus 로고
    • note
    • 28. Every candidate was calculated as the protonated form at the nitrogen in the pyridine ring.
  • 43
    • 85038550057 scopus 로고    scopus 로고
    • note
    • 31. Though we have postulated it would be reasonable that the enolization process started from the most stable conformer of each substrate, there might be a possibility that the transformation occurred from the less stable conformer of the starting substrate to the less stable one of the terminal product.
  • 44
    • 85038539166 scopus 로고    scopus 로고
    • note
    • 10 because of the small amount of natural UK-3A. In the private communication from Prof. M. Taniguchi and Dr. O. Sakanaka, they were reported as δ 3.08 ppm and δ 65.1 ppm, respectively.
  • 45
    • 85038550709 scopus 로고    scopus 로고
    • note
    • 4 segment in the nine-membered dilactone were both chiral, we believe that the optical purity of our γ-lactone 25 is excellent.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.