The pentasaccharide fragment α-d-Man-(1 → 5)-[α-d-Kdo-(2 → 4)-]α-d-Kdo-(2 → 6)-β-d-GlcNAc-(1 → 6)-α-d-GlcNAc equipped with a 3-aminopropyl spacer moiety was prepared by a sequential assembly of monosaccharide building blocks. The glucosamine disaccharide-as a backbone surrogate of the bacterial lipid A region-was synthesized using an 1,3-oxazoline donor, which was followed by coupling with an i...

Chiral N-protected α-amino aryl-ketones are one of the useful precursors used in the synthesis of various biologically active compounds and can be constructed via Friedel-Crafts acylation of N-protected α-amino acids. One of the drawbacks of this reaction is the utilization of toxic, corrosive and moisture-sensitive acylating reagents. In peptide construction via amide bond formation, N-hydroxy...

Treatment of O-benzyl protected S-glucosyl phosphorothioates with 1,3,5-trimethoxybenzene in the presence of iodine or boron trifluoride etherate led to appropriate aryl C-Dglucosides. The reaction of O-benzyl and O-acetyl-protected phosphorothioates of monosaccharides with allyltrimethylsilane, using boron trifluoride etherate as activator, gave mainly or exclusively, the corresponding 3-(α-Dg...

a simple and efficient one-pot, three-component strecker reaction of protected amino acids, aromatic aldehydes, and trimethylsilyl cyanide has been developed for the synthesis of chiral α-amino nitriles. the reaction was carried out in the presence of catalytic amount of phosphotungstic acid (h3[p(w3o10)4]) as an environmentally friendly catalyst.

A simple and efficient method for the synthesis of N,N'-orthogonally protected imide tethered peptidomimetics is presented. The imide peptidomimetics were synthesized by coupling the in situ generated selenocarboxylate of N(α)-protected amino acids with N(α)-protected amino acid azides in good yields. The protocol was also successfully applied for the synthesis of hybrid tripeptidomimetics bear...

We report a very mild synthesis of N-protected α-methylamines from the corresponding amino acids. Carboxyl groups of amino acids are reduced to iodomethyl groups via hydroxymethyl intermediates. Reductive deiodination to methyl groups is achieved by hydrogenation or catalytic transfer hydrogenation under alkaline conditions. Basic hydrodehalogenation is selective for the iodomethyl group over h...

The preparation of a crystalline, peracetyl adamantanyl thiosialoside donor protected by an isothiocyanate group is described. On activation at -78 °C in the presence of typical carbohydrate acceptors, this donor gives high yields of the corresponding sialosides with exquisite α-selectivity. The high selectivity extends to the 4-O-benzyl-protected 3-OH acceptors, which are typically less reacti...

The protecting group tetraisopropyldisiloxane-1,3-yl has been investigated for simultaneous protection of two hydroxyls on pentopyranosides. Methyl α-D-xylopyranoside is protected in excellent regioselectivity and high yield to form the 2,3-protected xylopyranoside whereas methyl β-D-xylopyranoside gives the 3,4-protected product also with excellent regioselectivity.

An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction-olefination process. The sequential reduction with DIBAL-H at -78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate t...

Enantiopure N(Boc)-β(3)-amino nitriles, valuable synthetic intermediates in the multistep homologation of α-amino acids, were alkylated using n-BuLi as base. Alkylations afforded easily separable, almost equimolecular mixtures of diastereomeric N(Boc)-protected syn and anti β(2,3)-amino nitriles. Suitable manipulations of both cyano and amino groups eventually led to enantiopure N- and/or C-pro...