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Volumn 1996, Issue 6, 1996, Pages 507-508

A Simple One-Pot Preparation of N,N′-Unsymmetrical Ureas from N-Boc Protected Primary Anilines and Amines

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EID: 0000095112     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1996-5476     Document Type: Article
Times cited : (56)

References (17)
  • 2
    • 0003405157 scopus 로고
    • Thieme, Stuttgart
    • Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis, 2nd ed.; Wiley: New York, 1991, p327; Kocienski, P. J. Protecting Groups; Thieme, Stuttgart, 1994, p192.
    • (1994) Protecting Groups , pp. 192
    • Kocienski, P.J.1
  • 12
    • 85033758283 scopus 로고    scopus 로고
    • note
    • The enantiomeric excess of both starting carbamates were evaluated by chiral HPLC and were found to be 99.6% ee for the (L) isomer and 99% ee for the (D) isomer. Experiments were performed at ambient temperature and with UV detection at 220 nm. A chiralcel OD column (250 x 4.6 mm I.D., Interchim, Montluçon, France) was used with the following mobile phase: n-hexane - 2-propanol 90 - 10; flow rate, 0.5 ml/min.
  • 13
    • 85033755870 scopus 로고    scopus 로고
    • note
    • HPLC conditions for the ureas: Chiralcel OD (250 x 4.6 mm I.D.), n-hexane - ethanol 70 - 30 modified with 0.1% diethylamine, 220 nm, 0.5 ml/min.
  • 17
    • 85033750482 scopus 로고    scopus 로고
    • note
    • Method A: A THF solution of the amine anion prepared from amine 2 and n-BuLi is added dropwise at room temperature to a solution of carbamate 1 in THF. The reaction is then heated at reflux for the given time. Method B: The carbamate 1 and the amine 2 are dissolved in the solvent at room temperature prior to the addition of the base. The reaction is then heated at reflux for the given time. Method C: A THF solution of the amine anion prepared from amine 2 and n-BuLi is added dropwise at -78°C to a solution of carbamate 1 in THF. The reaction is then heated at reflux for the given time.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.