Maltose trimethylsilylation

With simple compounds, the trimethylsilylation reaction is rapid, but, if the reaction proceeds slowly, short reaction-times lead to incomplete substitution this is generally manifest on the gas chromatogram because of the presence of an unexpectedly large number of peaks.117 Maltose has been reported to require reaction for at least 30 minutes,118 and the time needed for complete trimethylsilylation of amino sugars has been examined by Oates and Schrager.36... 

The readily accessible peracetates of lactose, maltose, and melibiose are converted in good yields into the corresponding 1,2-trans glycobiosyl azide hepta-acetates more conveniently than by the previously published procedure for the preparation of hepta-(9-acetyl-p-cellobiosyl azide (59). Later this formation of hepta-(9-acetyl-p-lactosyl azide (60) was reported as a novel procedure, and the corresponding melibiosyl derivative was again described. Compound 59 can also be obtained from an orthoester precursor with trimethylsilyl azide as already described, but this route does not enjoy any particular preparative advantage. 

Scheme 39. Partial fragmentation of octa-O-trimethylsilyl maltose, 39.

The preparation of the octa-Q-benzoyl-aldobiononitriles of cellobiose, gentiobiose, lactose, and maltose from the unprotected oximes has been effected by treatment with benzoyl chloride in pyridine at SO C. Reaction of melibiononitrile perbenzoate with methanolic ammonia yielded the 1,1-dibenzamido-derivative (37) as the major product, isolated in 38% yield.The erythro- and threo-cyanohvdrins (38) were obtained in a 4 1 ratio from 2,3-Q-isopropylidene-D-glyceraldehyde on reaction with trimethylsilyl cyanide, and were converted to the four carbon lactone synthons (39). The chiral hexane-1,6-dinitrile (40) has been synthesized CHjOH... 

The simultaneous g.c. analysis of sugars (Ara, Rha. Fiu, Gal, Glc, sucrose, maltose and raffinosc), sorbitol, and nine organic acids in vegetables and strawberries utilized derivatives produced by oximation - trimethylsilylation."... 

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