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Volumn 8, Issue 15, 2006, Pages 3311-3314

Efficient access to cyclic ureas via Pd-catalyzed cyclization

Author keywords

[No Author keywords available]

Indexed keywords

BENZIMIDAZOLE DERIVATIVE; DRUG DERIVATIVE; IMIDAZOLE DERIVATIVE; PALLADIUM; PYRIDONE DERIVATIVE; UREA;

EID: 33746883528     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol061233j     Document Type: Article
Times cited : (73)

References (24)
  • 1
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    • and references cited therein
    • For selected examples, see: (a) Kuethe, J. T.; Wong, A.; Davies, I. W. J. Org. Chem. 2004, 69, 7752-7754 and references cited therein.
    • (2004) J. Org. Chem. , vol.69 , pp. 7752-7754
    • Kuethe, J.T.1    Wong, A.2    Davies, I.W.3
  • 8
    • 0033564994 scopus 로고    scopus 로고
    • For examples of intramolecular Pd-catalyzed amidation, see: (a) Yang, B. H.; Buchwald, S. L. Org. Lett. 1999, 1, 35-37.
    • (1999) Org. Lett. , vol.1 , pp. 35-37
    • Yang, B.H.1    Buchwald, S.L.2
  • 10
    • 0038644140 scopus 로고    scopus 로고
    • In a study directed toward the sysnthesis of benzothiazoles via cyclization of o-bromophenylthioureas, two benzimidazolones were prepared by Pd-catalyzed urea cyclization under relatively harsh conditions/high catalyst loadings; see: Benedi, C.; Bravo, F.; Uriz, P.; Fernández, E.; Claver, C.; Castillón, S. Tetrahedron Lett. 2003, 44, 6073-6077.
    • (2003) Tetrahedron Lett. , vol.44 , pp. 6073-6077
    • Benedi, C.1    Bravo, F.2    Uriz, P.3    Fernández, E.4    Claver, C.5    Castillón, S.6
  • 11
    • 0037140736 scopus 로고    scopus 로고
    • For examples of intermolecular Pd-catalyzed amidation using cyclic ureas, see: (a) Yin, J.; Buchwald, S. L. J. Am. Chem. Soc. 2002, 124, 6043-6048.
    • (2002) J. Am. Chem. Soc. , vol.124 , pp. 6043-6048
    • Yin, J.1    Buchwald, S.L.2
  • 12
    • 20444449293 scopus 로고    scopus 로고
    • For examples of Cu-catalyzed amidation using cyclic and acyclic ureas, see: (b) Trost, B. M.; Stiles, D. T. Org. Lett. 2005, 7, 2117-2120.
    • (2005) Org. Lett. , vol.7 , pp. 2117-2120
    • Trost, B.M.1    Stiles, D.T.2
  • 14
    • 0038003832 scopus 로고    scopus 로고
    • For Pd- and Cu-catalyzed synthesis of 2-aminobenzimidazoles via intramolecular C-N bond formation between an aryl bromide or iodide and a guanidine, see: Evindar, G.; Batey, R. A. Org. Lett. 2003, 5, 133-136.
    • (2003) Org. Lett. , vol.5 , pp. 133-136
    • Evindar, G.1    Batey, R.A.2
  • 18
    • 84987251005 scopus 로고
    • For a review on the use of CSI for various transformations, see: Dhar, D. N.; Murthy, K. S. K. Synthesis 1986, 437-449.
    • (1986) Synthesis , pp. 437-449
    • Dhar, D.N.1    Murthy, K.S.K.2
  • 20
    • 33746916659 scopus 로고    scopus 로고
    • note
    • Notably, the published procedures advocate a "normal" addition protocol, in which CSI is added to the substrate. Based on the observations from the current work, this could account for the moderate yields obtained in these cases.
  • 21
    • 33746883768 scopus 로고    scopus 로고
    • note
    • Attempted thermal cyclizations in a variety of solvents (DMSO, MeCN, NMP, water, toluene, i-PrOH, DMAc, pyridine, n-BuOH, and AcOH) were not successful, generally returning unchanged starting material.
  • 22
    • 0034794463 scopus 로고    scopus 로고
    • Cu-catalyzed conditions were less successful for this reaction, affording only 67% conversion of starting material. See: Klapars, A.; Antilla, J. C.; Huang, X.; Buchwald, S. L. J. Am. Chem. Soc. 2001, 123, 7727-7729.
    • (2001) J. Am. Chem. Soc. , vol.123 , pp. 7727-7729
    • Klapars, A.1    Antilla, J.C.2    Huang, X.3    Buchwald, S.L.4
  • 23
    • 33746902625 scopus 로고    scopus 로고
    • note
    • Again, the mass balance was found in the urea cleavage side reaction, apparently suppressed under the less basic conditions.
  • 24
    • 33746907307 scopus 로고    scopus 로고
    • note
    • 2 was also ineffective in attempts to cyclize the bromoaniline substrate.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.