Amino sugars preparation

D-Glycopyranosiduronic Acids from Amino Sugars, Prepared by Catalytic Oxidation... 

The use of 4-chloro-sugars as intermediates in amino-sugar preparations is referred to in Chapter 8. 

The diphenylmaleimide is prepared from the anhydride, 33-87 % yield, and cleaved by hydrazinolysis, 65-75% yield. It is stable to acid (HBr, AcOH, 48 h) and to mercuric cyanide. It is colored and easily located during chromatography, and has been prepared to protect steroidal amines and amino sugars. " ... 

Nitro and 3-amino sugars have been prepared via stepv/ise constnicdon from acyclic precursors by the nitro-aldol strategy as shovm in Scheme 3 8... 

Jdger and co-workers have prepared various amino sugars by the reduction of the con sponding fi-nitro alcohols with H-, and Pd/C, as exemplified in Eq 6 49 fsee Chapter 3 ... 

Preparation of the TMS derivative Add 0.5 ml of TRI-SIL Z reagent (trimethylsilylimidazole in pyridine) to 1-5 mg of the sample. (This derivatizing preparation does not react with amino groups and tolerates the presence of water.) Heat in a sealed vial at 60° until the sample is dissolved. An alternate method is to let the reaction mixture stand at room temperature for at least 30 minutes (or overnight). This procedure is not appropriate for amino sugars. 

Preparation of TMS derivative To derivatize the amino sugars as well as the nonamino sugars, substitute TRI-SIL TBT or TRI-SIL/BSA (Formula P) reagent for TRI-SIL Z and follow the procedure given in Section I,A,1. 

The amino sugar counterparts of D-glucuronic acid and nonsulfated L-iduronic acid in heparin are either N-acetylated, or nonsulfated at C-6, or both. 2-Acetamido-2-deoxy-D-glucosyl residues account for only a minor proportion of the total hexosamine in heparin, and are especially low in beef-lung preparations (see Table II).8,138,147 -149 In contrast, they... 

Residues of non-N-substituted 2-amino-2-deoxy-D-glucose constitute only a tiny fraction (if any) of the total amino sugar of heparin and heparan sulfate. Although free amino groups are produced in the biosynthesis20,23 of heparin (between stages 1 and 2, see Scheme 1), the small proportions occasionally found in heparin and heparan sulfate preparations are most probably the result of some N-desulfation during extraction, or purification, or both. 

The hydroxy groups in natural products like, for example, the macrolide antibiotics erythromycin, 1"1 and desmycosin, 2001 2011 as well as the 3-(hydroxymethyl)-2- or 3-cephems 2021 and derivatives of the amino sugar garamin 2031 have been converted into the carbamate function with CDI and amines. In the case of aminoglycoside antibiotics of the sisomicin series, thiocarbamates or dithiocarbamates have been prepared from alcohols or thiols using ImCSIm and amines.12041... 

Nitroacetaldehyde diethyl acetal is prepared by the reaction of nitromethane with triethyl orthoformate in the presence of ZnCl2 (Eq. 5.8).17 Jager and coworkers have used this reagent for the synthesis of amino sugars via nitro-aldol reaction.18 Preparation of this useful reagent is now described in volume 74 of Organic Synthesis.19... 

The reduction of nitro sugars with H2 in the presence of Raney Ni is one of the standard methods for the preparation of amino sugars (Eq. 6.47).93... 

In carbohydrate chemistry, the most described method for the preparation of saccharidic thionocarbamates involves preliminary introduction of the amine function on a partially or non-protected saccharidic template. The condensation of amino sugars with carbon disulfide or thiophosgene leads to cyclization in 1,3-oxazolidine- or l,3-oxazine-2-thiones. This reaction involves the formation of an intermediate isothiocyanate, which reacts further with a 3- or y-located hydroxyl group. The viability and facility of this process depends on the saccharidic ring size and the inherent strain. Some major rules can be put into light from the cases studied 30... 

Reaction of nitromethane and monosaccharide-derived dialdehydes is a useful tool that has been broadly used for the preparation of nitro and amino sugars, and carbocycles.30 Dialdehydes can easily be obtained by oxidative cleavage of conveniently protected monosaccharides with sodium periodate. Their subsequent Henry reaction with a nitroalkene, commonly nitromethane, usually gives isomeric mixtures that require the isolation of the major isomer.31 Thus, treatment of the D-ribose derivative 27 with sodium periodate gave dialdehyde 28, which was subjected to a Henry reaction with nitromethane, to afford nitrosugar 29 as an epimeric mixture (Scheme 11).32... 

In this manner, several fractions were prepared which contained between 97.5 and 98.6% unidentified N, but only 0.84% amino add N, 0% amino sugar N, and 0.53 % ammonia N. 

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