Glucose ammonolysis

On the other hand, if ammonolysis first occurred at carbon atoms 4 or 5, the formation of a cyclic hemiacetal would be favored, and the possibility of obtaining a diacetamide would be correspondingly decreased. Such an explanation accounts for the formation of iV-acetyl-D-gluco-furanosylamine reported by Hockett and Chandler. Here, the first product of the reaction is a D-glucofuranose, which then condenses with acetamide. A similar explanation accounts for the results obtained by Brigl, Miihlschleger and Schinle with 2-thioethyl-3,4,5,6-tetrabenzoyl-oZde%do-D-glucose. 

Brigl and coworkers9 discovered the first example showing that the formation of aldose amides is not restricted to the degradation of acylated nitriles of aldonic acids. By ammonolysis of 2,3,4,5,6-penta-O-benzoyl-aldehydo-n-glucose (16), they obtained l,l-bis(benz-amido)-l-deoxy-D-glucitol (17). 

The similarity of the products obtained by ammonolysis, either of acylated nitriles, or of acylated aldehydo monosaccharides having one carbon atom less than the corresponding nitriles, was verified12 by ammonolysis of 2,3,4,5,6-penta-O-acetyl-aWehydo-D-glucose (20), which afforded the same N-acetyl-a-D-glucofuranosylamine (15) as that obtained from the peracetylated heptononitrile 14. 

An experiment whose results support certain mechanistic views (see Section VI, p. 110) was the ammonolysis of 2,3,4,6-tetra-O-benzoyl-D-glucopyranosylamine,30 which afforded a mixture of D-glucose and D-glucosylamine in 95% yield, and only 1.4% of l,l-bis(benzamido)-l-deoxy-D-glucitol (17) with traces of N-benzoyl-D-glucopyranosylamine. 

Imidazole derivatives were not detected in the ammonolysis of aldose esters, and pyrazines only appeared in the case of the per-nicotinates of D-glucose and D-xylose, as already described. 

The presence of alkoxide ion would enhance the rate of ammonolysis, and the formation of bis(amido) derivatives by an ortho-ester mechanism (see Section VI, p. 110) would be partially suppressed in the competitive set of reactions. Thus, ammonolysis of penta-O-benzoyl-D-glucose in the presence of 5 mmolar proportions of sodium meth-oxide showed a decrease of 11% in the yield of the bis(benzamido)-glucitol derivative as compared with the same reaction conducted without added methoxide ion.47... 

Compound 5 (see p. 82) was allowed to react83 with ethanolic ammonia-15N in the presence of an excess of acetamide-14N, and compound 6 containing a percentage of 15N similar to that of the ammonia employed was obtained, showing that, actually, the reaction occurs by an intramolecular mechanism. Were the mechanism intermolecular, in accordance with Wohl s views, the percentage of 15N in 6 would have been lower. Likewise, ammonolysis of D-glucose pentabenzo-... 

MacDonald and H. O. L. Fischer372 oxidized D-glucose diethyl dithioacetal pentaacetate (24) and its D-manno isomer with mono-peroxyphthalic acid in ether, isolating not the epimeric disulfones but a common product, to which they assigned the structure 3,4,5,6-tetra- O - acetyl -1,2- dideoxy-1,1 -bis (ethylsulfonyl)-D-arabtno-hex-1-enitol (176). Ammonolysis of 176 and reacetylation afforded 177, which was also prepared by oxidation of 2-acetamido-3,4,5,6-tetra-0-acetyl-2-deoxy-D-glucose diethyl dithioacetal, whereas the action of hydrazine in methanol on 176 produced a retroaldol reaction (and saponification) affording D-arabinose (179, 40% yield) and bis(ethyl-sulfonyl)methane (178). The latter reaction accords with earlier ob-... 

Dermocybin-l-P-D-glucopyranoside (299) was similarly cleaved with P-glucosidase and, with aqueous ammonia, the deoxyaminogluco-side (317) was produced indicating a free 5,7,8-trihydroxylation pattern in the parent glucoside. Hydrolysis of (317) with mineral acid (Scheme 51) afforded the aminoquinone (318) which had earlier been isolated upon ammonolysis of dermocybin itself 616). The position of the glucose residue in (299) was further corroborated by the acylation shifts observed in the H-n.m.r. spectra 614, 615). 

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