D. C. Ionescu

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The N-dicyclopropylmethyl (Dcpm) residue, introduced into amino acids via reaction of dicyclopropylmethanimine hydrochloride with an amino acid ester followed by sodium cyanoborohydride or triacetoxyborohydride reduction, can be used as an amide bond protectant for peptide synthesis. Examples which demonstrate the amelioration of aggregation effects include(More)
[reaction: see text] Isolated Fmoc amino acid fluorides have previously been shown to be among the most efficient reagents for peptide bond formation. Now, it has been found that anionic, polyhydrogen fluoride additives are capable of diverting many of the classical peptide coupling processes to acid fluoride couplings. Examples include the use of N-HBTU or(More)
Nine analogues of methotrexate, in which the side chain is modified by replacement of the terminal glutamyl moiety with other amino acids, were synthesized from 2,4-diamino-6-(chloromethyl)pteridine. None of these compounds exhibited significant activity against L1210.
The University of Ottawa has recently established a new undergraduate program in software engineering. In this paper we review how we resolved several issues that were raised during the development of the program. These key issues are: a) How should the program be made distinct from computer science and computer engineering programs? b) What should be the(More)
Of the three theoretically possible, Bsmoc-related, naphthothiophene sulfone-based amino-protecting groups, the two most readily available derivatives, the alpha- and beta-Nsmoc analogues, have been examined as substitutes for the Bsmoc residue in cases where the latter lead to oily protected amino acids or amino acid fluorides. All of the naphtho systems(More)