Streptosonic acid monolactone

Hydrolysis of pentaacetylstreptobiosamic acid monolactone in refluxing 2.5 N hydrochloric acid yielded a crystalline compound derived from the streptose moiety. This compound was designated streptosonic acid monolactone and was further characterized as its diacetate. The hydrolyzate was shown to contain N-methyl-L-glucosamine. 

Analysis of streptosonic acid monolactone showed a composition corresponding to the formula CsHgOe. The formulation of this compound as a monolj,ctone of a dibasic acid was based on its behavior during potentiometric titration, when neutral equivalents of 175 and 87.5 were... 

Confirmatory evidence for streptosonic acid diamide existing as structure XXI was obtained by a study of the oxidation products of streptosonic acid monolactone (XXIII). When this compound was oxidized with two moles of periodic acid, two of the cleavage products were identified as glyoxylic acid (XXIV) and oxalic acid (XXV). The suggested course of the oxidation, on the basis of structure XXIII, is shown... 

Assuming structure XXIII for streptosonic acid monolactone and structure XX for didesoxydihydrostreptobiosamine, streptobiosamic acid monolactone would be XXVI. 

Unlike the other streptobiosamine derivatives (Table IV, page 383) streptobiosamic acid monolactone formed a pentaacetyl derivative " rather than a tetraacetyl compound. Also, acetylation of streptosonic acid monolactone yielded a diacetyl derivative. It was pointed out that either the ordinarily resistant tertiary hydroxyl group had been acetylated in these compounds (XXVII) or that the lactone ring had shifted from the 7- to the /3-position, during the acetylation, with the introduction of an acetyl group at carbon atom four (XXVIII). Whatever the positions of the ester groupings in pentaacetylstreptobiosamic... 

Fried, Walz and Wintersteiner isolated 4-desoxy-i/-glycero-tetrose phenylosazone (XLII) from the reaction of streptobiosamine hydrochloride with phenylhydrazine and thus demonstrated that streptose was configurationally an l sugar. The levorotation ([a] o —37°, water ) of streptosonic acid monolactone (XXIII) might also be adduced as contributory evidence for the l configuration of the penultimate carbon of streptose, should Hudson s lactone rule be applicable to this rather complex structure. 

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