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Volumn , Issue 14, 2007, Pages 2252-2256

Synthesis of highly functionalized isoxazoles via base-promoted cyclocondensation of stable nitrile oxides with active methylene compounds

Author keywords

Active methylene compounds; Benzonitrile oxide; Cyclocondensation; Isoxazole; Molecular sieves

Indexed keywords

CARBENE; ISOXAZOLE DERIVATIVE; NITRIC OXIDE;

EID: 34548862351     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-2007-985561     Document Type: Article
Times cited : (22)

References (23)
  • 18
    • 0344887064 scopus 로고    scopus 로고
    • Although the pKa of methanesulfonylacetone (6) has not been documented so far, we estimated it to be higher than that of ethyl acetoacetate (3) by analogy from the pKa of dimethyl sulfone (31.1 in DMSO) and EtOAc (29.5 in DMSO, a) Bordwell, F. G. Acc. Chem. Res. 1988, 21, 456
    • Although the pKa of methanesulfonylacetone (6) has not been documented so far, we estimated it to be higher than that of ethyl acetoacetate (3) by analogy from the pKa of dimethyl sulfone (31.1 in DMSO) and EtOAc (29.5 in DMSO): (a) Bordwell, F. G. Acc. Chem. Res. 1988, 21, 456.
  • 20
    • 34548863317 scopus 로고    scopus 로고
    • Structure of 21 was confirmed by X-ray crystallographic analysis (CCDC 647875).
    • Structure of 21 was confirmed by X-ray crystallographic analysis (CCDC 647875).
  • 21
    • 34548812539 scopus 로고    scopus 로고
    • For conventional synthesis of the isoxazolone via the reaction of hydroxylamine and 3-oxo ester, see reference 4a. For the access from nitrile oxides, see: (a) Scarpati, R.; Sorrentino, P. Gazz. Chim. Ital. 1959, 8, 1525.
    • For conventional synthesis of the isoxazolone via the reaction of hydroxylamine and 3-oxo ester, see reference 4a. For the access from nitrile oxides, see: (a) Scarpati, R.; Sorrentino, P. Gazz. Chim. Ital. 1959, 8, 1525.
  • 23
    • 34548851684 scopus 로고    scopus 로고
    • Typical Experimental Procedure for the Synthesis of Isoxazole 14 Using 4 Å MS: To a solution of 2-bromo-6-methoxybenzonitrile oxide (12; 214 mg, 0.937 mmol) and benzoylacetonitrile (4; 161 mg, 1.11 mmol) in i-PrOH (3.1 mL) was added 4 Å MS (938 mg) at r.t. The red suspension was heated at 50°C for 2 h. After cooling, the mixture was filtered through a Celite® pad, and the filtrate was concentrated in vacuo. The residue was purified by silica gel column chromatography (hexane-EtOAc, 85:15) to give 14 (253 mg, 76, as a yellow solid. Recrystallization of 14 from acetone-hexane gave a colorless prism; mp 177.2-177.6°C. 1H NMR (300 MHz, CDCl3, δ, 3.85 (s, 3 H, 7.00 (dd, J, 2.0, 7.6 Hz, 1 H, 7.33 (dd, J, 2.0, 7.6 Hz, 1 H, 7.37 (dd, J, 7.6, 7.6 Hz, 1 H, 7.55-7.64 (m, 3 H, 8.12-8.19 (m, 2 H, 13C NMR 75 MHz, CDCl3, δ, 56.1, 90.0, 110.2, 11
    • 1H NMR...


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.