Synthesis of orthogonally protected and functionalized bacillosamines

Abstract

The synthesis of bacillosamines carrying different functionalities at their C-2 and C-4 amine groups is described for the first time.

Total Syntheses of Conjugation‐Ready Repeating Units of Acinetobacter baumannii AB5075 for Glycoconjugate Vaccine Development

“…The Staudinger reaction failed for this trisaccharide, [37] while treatment with 1,3‐propanedithiol was too mild to reduce the azide, instead, one chlorine of the TCA group was cleaved to give a 2‐dichloroacetamido‐4‐azido product. [ 34 , 38 ] Finally, treatment of 36 with excess zinc and acetic acid at 40 °C in THF successfully converted the azide to the amine, subsequent coupling with freshly made ( S )‐3‐ O ‐benzylbutyryl chloride[ 39 , 40 ] gave 37 in 60 % yield over two steps. The Lev esters were cleaved to get diol 48 with two hydroxyl groups ready for inversion.…”

Total Synthesis of the All-Rare Sugar-Containing Pentasaccharide Repeating Unit of the O-Polysaccharide of Plesiomonas shigelloides Strain 302-73 (Serotype O1)

“…Recently, Codeé and co-workers have reported a synthesis of orthogonally protected D-bacillosamine derivatives via azidoselenation of D-fucal through a stepwise process. 24 For the synthesis of D-bacillosamine acceptor 6, which bears three differentially protected amino groups, we started with the known D-fucosamine derivative 11, 17,18 which could be readily prepared from D-rhamnose thioglycoside via our one-pot double-displacement methodology. As shown in Scheme 2a, compound 11 was subjected to azide reduction using Zn, AcOH conditions followed by selective protection of amine using trichloroacetyl chloride to obtain D-fucosamine derivative L-Fucosamine building blocks 7a and 7b were synthesized by a modification of our established protocol involving a highly regioselective one-pot S N 2 displacements of 3-OBz-protected L-rhamnosyl 2,4-bistriflates (Scheme 2b).…”

“…With this retrosynthetic plan, we began with the synthesis of the differentially functionalized d -bacillosamine acceptor 6 . Recently, Codée and co-workers have reported a synthesis of orthogonally protected d -bacillosamine derivatives via azidoselenation of d -fucal through a stepwise process . For the synthesis of d -bacillosamine acceptor 6 , which bears three differentially protected amino groups, we started with the known d -fucosamine derivative 11 , , which could be readily prepared from d -rhamnose thioglycoside via our one-pot double-displacement methodology.…”

Synthesis of Oligosaccharides Resembling the Streptococcus suis Serotype 18 Capsular Polysaccharide as a Basis for Glycoconjugate Vaccine Development

“…C6-Deoxygenation was achieved via iodination with NaI in refluxing acetone (93% yield of 15 ), and subsequent dehalogenation/reduction with tributyltin hydride yielded fucosamine 11 derivative 16 (76%). Selective acylation of the amine in 16 using trichloroacetyl choride 12 afforded 17 in 85% yield. The triflation of 17 using triflic anhydride followed by C4 inversion with stoichiometric amounts of sodium azide provided d -bacillosamine derivative 13 18 in 68% yield over two steps.…”

“…C6-Deoxygenation was achieved via iodination with NaI in refluxing acetone (93% yield of 15), and subsequent dehalogenation/reduction with tributyltin hydride yielded fucosamine 11 derivative 16 (76%). Selective acylation of the amine in 16 using trichloroacetyl choride 12 C4 inversion with stoichiometric amounts of sodium azide provided D-bacillosamine derivative 13 18 in 68% yield over two steps. Oxidative cleavage of the naphthyl ether (Nap) by 2,3dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) afforded Dbacillosamine derivative 14 building block 6 in 90% yield.…”