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Volumn 13, Issue 11, 2011, Pages 2876-2879

Potassium hydroxide/dimethyl sulfoxide promoted intramolecular cyclization for the synthesis of benzimidazol-2-ones

Author keywords

[No Author keywords available]

Indexed keywords

BENZIMIDAZOL 2 ONE; BENZIMIDAZOL-2-ONE; BENZIMIDAZOLE DERIVATIVE; DIMETHYL SULFOXIDE; HYDROXIDE; POTASSIUM DERIVATIVE; POTASSIUM HYDROXIDE; UREA;

EID: 79957859393     PISSN: 15237060     EISSN: 15237052     Source Type: Journal    
DOI: 10.1021/ol2008878     Document Type: Article
Times cited : (70)

References (36)
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    • For Pd-catalyzed reactions, see: Xu, X.-J.; Zong, Y.-X. Tetrahedron Lett. 2007, 48, 129
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  • 22
    • 0010954389 scopus 로고
    • For a review on KOH-DMSO mixtures as "superbases", see
    • For a review on KOH-DMSO mixtures as "superbases", see: Trofimov, B. A. Sulfur Rep. 1992, 74, 207
    • (1992) Sulfur Rep. , vol.74 , pp. 207
    • Trofimov, B.A.1
  • 26
    • 70349783568 scopus 로고    scopus 로고
    • Great care was taken to avoid the presence of trace metals in the reaction mixture. Those measures included the transition-metal-free synthesis of the starting materials, reagent transfers with plastic spatulas, and the use of new glassware for the cyclization reactions. Such precautions appeared advisable in light of the recent reports on trace metal effects on cross-coupling reactions. For examples, see
    • Great care was taken to avoid the presence of trace metals in the reaction mixture. Those measures included the transition-metal-free synthesis of the starting materials, reagent transfers with plastic spatulas, and the use of new glassware for the cyclization reactions. Such precautions appeared advisable in light of the recent reports on trace metal effects on cross-coupling reactions. For examples, see: Buchwald, S. L.; Bolm, C. Angew. Chem., Int. Ed. 2009, 48, 5586
    • (2009) Angew. Chem., Int. Ed. , vol.48 , pp. 5586
    • Buchwald, S.L.1    Bolm, C.2
  • 30
    • 79957810787 scopus 로고    scopus 로고
    • Also attempted cyclizations of 1e with 3 or 4 equiv of KOH (at 40 °C) remained unsuccessful. At 100 °C (using 2 equiv of KOH) only traces of 2b were detected after 22.5 h.
    • Also attempted cyclizations of 1e with 3 or 4 equiv of KOH (at 40 °C) remained unsuccessful. At 100 °C (using 2 equiv of KOH) only traces of 2b were detected after 22.5 h.
  • 31
    • 79957865570 scopus 로고    scopus 로고
    • Even at 70 bar of hydrogen pressure (RT, 22 h) formation of 3a was not observed, and the yield of 1-(cyclohexylmethyl)-3-phenyl-1,3- dihydrobenzoimidazol-2-one was only 32%.
    • Even at 70 bar of hydrogen pressure (RT, 22 h) formation of 3a was not observed, and the yield of 1-(cyclohexylmethyl)-3-phenyl-1,3- dihydrobenzoimidazol-2-one was only 32%.
  • 36
    • 79958850927 scopus 로고    scopus 로고
    • For a recent overview on metal-free arylations under basic conditions involving radical anions, see:; ChemCatChem 2011, DOI: 10.1002/cctc.201000431.
    • For a recent overview on metal-free arylations under basic conditions involving radical anions, see: Yanagisawa, S.; Itami, K. ChemCatChem 2011, DOI: 10.1002/cctc.201000431.
    • Yanagisawa, S.1    Itami, K.2


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.