Tritylation of glucose

Trimethylene bromide, 20, 25 Trimethylthiourea, 21, 84 Triphenylmethyl chloride, 22, 56 Tritylation of glucose, 22, 56 Trityl bromide, 22, 57 Trityl chloride, 22, 56 6-Trityl-/3-<7-glucose-1,2,3,4-tetra-ACETATE, 22, 56... 

The only dimethyl-D-fructose which has been characterized, 3,4-di-methyl-D-fructose, has been prepared by McDonald and Jackson141 from di-D-fructose anhydride I. Tritylation of this anhydride gives the 6,6 -ditrityl derivative which is methylated to 3,4,3, 4 -tetramethyl-6,6 -di-trityl-di-D-fructose anhydride I. Removal of the trityl groups followed by hydrolysis yields liquid 3,4-dimethyl-D-fructose, [ ]d —60.66° in water. It has also been obtained, with 4-methyl-D-fructose, from the hydrolysis of methylated di-D-fructose anhydride III. The structure of this dimethyl-D-fructose follows from its method of preparation from di-D-fructose anhydride I whose structure is known.10 McDonald and Jackson also prepared 3,4-dimethyl-D-fructose from inulin by the following method inulin — monotrityl inulin — monotrityl inulin diacetate — dimethyl monotrityl inulin — dimethyl isopropylidene-D-fructose — methyl dimethyl-D-fructoside —> 3,4-dimethyl-D-fructose. Its structure was confirmed by its oxidation without loss of methyl to the same lactol of the dimethyl dibasic acid obtained from 1,3,4-trimethyl-D-fructose (see page 78). The phenylosazone made from 3,4-dimethyl-D-fructose has m. p. 126° that from 3,4-dimethyl-D-glucose has not been recorded. 

In this manner 6-methyl-D-glucopyranose (XXIX) and some of its derivatives were synthesized from n-glucose derivatives containing a free hydroxyl group only in the 6-position. The 6-methyl ethers of D-mannose and of methyl a-n-mannoside were obtained similarly. Haworth and coworkers synthesized 2,3,4-trimethyl-n-glucose from 6-trityl-D-glucose and used the ether for the elucidation of structural problems. 

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