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Tetrahedron Letters
Volumn 26, Issue 37, 1985, Pages 4419-4422
Avermectin-milbemycin studies. 4. An expedient two-step preparation of p-hydroxybenzoates
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Indexed keywords

EID: 0000289310     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(00)88919-4     Document Type: Article
Times cited : (30)
References (16)
  • 7
    • 84918423077 scopus 로고    scopus 로고
    • For previous publications in this series see: Smith, A.B., III, Thompson, A.S., Tetrahedron Letters, in press.
  • 10
    • 84918423076 scopus 로고    scopus 로고
    • 4), evaporated and the residue chromatographed on silica [7:3 (v/v) hexane/etherl to give 188 mg (42%) of Z-ethyl-4-methyl-5,7-dioxo-2-non-enoate (2b) as a colorless oil.
  • 11
    • 84918423075 scopus 로고    scopus 로고
    • A typical procedure follows: Method A. Diketoester 2b (124 mg O.547 mmol) was dissolved in 0.18 M ethanolic sodium ethoxide (20 mL) under argon at room temperature. After 1 h, the mixture was partitioned between ether and dilute aqueous HCl (0.5 M). The organic phase was dried and evaporated, and the residue chromatographed on silica [3:2 (v/v) hexane/etherl to give 91 mg (80%) of 2c. Method B. A solution of 4b (43.2 mg, 0.166 mmol) in absolute ethanol (20 mL) was added dropwise over 4 h to a solution of triethylamine (1.0 mL) In absolute ethanol (20 mL) held at reflux under argon. After 18 h the solution was evaporated and the residue was chromatographed on silica [3:2 (v/v) hexane/ ether] to give 28.1 mg (70%) of 4c as a colorless oil.
  • 12
    • 84918423074 scopus 로고    scopus 로고
    • 3) δ 7.8 (m, 2H), 7.5 (m, 3H), 6.97 (dt, J = 15, 7 Hz, 1H), 6.23 (s, 1H), 6.15, br d, J = [[Truncated]]

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.