Bzl, benzyl

BjiHn] interacts with the Bn Hu anionic unit as shown in Figure 2.1-38. This leads to a distortion of the Bn cluster while the anion of the ammonium salt [N(bzl)Et3]2[BnHn] (bzl = benzyl) has almost perfect C2o symmetry [101]. 

Monomers are all 1,6-anhydroaldohexose derivatives. Parent monosaccharides are indicated by the conventional abbreviations, and maltose by Mai. Other symbols Ac, 3-O-acetyl An, 1,6-anhydro Bzl, benzyl Bbl, p-bromobenzyl Cro, 3-0-(2-butenyl) Ip, 3,4-O-isopropylidene and Xy, p-methylbenzyl (p-xylyl). 6 10 mole-% PF . 

Groups Me, methyl Et, ethyl Pr, propyl Bu, butyl Ac, acetyl Cp, cyclopentadienyl Ph, phenyl Bzl, benzyl Mes, mesityl Ar = TtbPh, tri-tertiary-butylphenyl Ad, adam-antyl Tms, trimethylsilyl. 

Fig. 7. Crude HPLC of Cyclo-[Phe-Asn-Val-(D)Glu-Ala-Gly]. HPLC A after one treatment of TFMSA/TFA/p-cresol. HPLC B after two treatments of TFMSA/TFA/ p-cresol. C = Cyclic peptide, Bzl = benzyl. Tit = Trityl, L = Linear.

Fig. 4a. Pathways of hydroxamic acid syntheses of siderophores containing Ns-hydroxyornithine building blocks, a) Starts with e-nitro-L-norvaline. Schemes b) and c) start with ornithine derivatives protected at N5 with CBZ (benzyloxycarbonyl) and Tos (toluenesulfonate), BZL (benzyl), respectively Fig. 4b. Scheme of the synthesis of aerobactin. Protected g-hydroxynorleucine 1 (P = BOC,P = CH3) is transformed into the protected hydroxamic acid 2. Deprotection of the a-NH2 grqup enables alkylation of the o-substituted hydroxamate to give compound 3...

Abbreviations Ala, alanine Leu, leucine BLAsp, /3-benzyl L-aspartate BLGlu, 7-benzyl L-gluta-mate MLGlu, 7-methyl L-glutamate Val, valine lie, isoleucine Gly, glycine Pro, proline Bu, butyl Et, ethyl Bzl, benzyl Me, methyl Z, benzyloxycarbonyl Nps, (o-nitrophenyl)sulphenyl. 

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