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Synthesis 1997; 1997(7): 759-763
DOI: 10.1055/s-1997-1418
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pH-Controlled Selective Protection of Polyaza Macrocycles

Zoltan Kovacs, A. Dean Sherry*
  • *Department of Chemistry, The University of Texas at Dallas, P.O. Box 830688, Richardson, Texas 75083-0688, USA, Fax +1(972)8832925
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Publication History

Publication Date:
31 December 2000 (online)

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Piperazine (1), tetraazacyclododecane 3 and pentaazacyclopentadecane 4 react with chloroformates in acid solution to give the selectively protected carbamate derivatives 1a, 3a-d, and 4a. The benzyloxycarbonyl derivatives 3d and 4a were alkylated with tert-butyl bromoacetate and removal of the benzyloxycarbonyl protection by catalytic hydrogenation afforded tert-butyl esters 5b and 6b in good yields.

polyaza macrocycles - selective protection - benzyloxycarbonyl group - catalytic hydrogenation - t-butyl ester