Ditrityl ether

Trityl chloride reacts more readily with primary than with secondary hydroxyl groups, so that it is possible to isolate 1,6-ditrityl ethers. ... 

Selective tritylation of methyl oc-L-rhamnopyranoside yielded 57% of the 3-0-trityl derivative, together with 1 % of the 2-0- and 3 % of 4-0-trityl isomers. For methyl P-L-rhamnopyranoside, 34% of the 3-trityl and 17% of the 4-trityl ether were obtained [315]. Similarly, the 3,6-ditrityl ether is the major product of ditrityl-ation of methyl and benzyl a-D-mannopyranosides [316]. The corresponding a-D-glucopyranosides yielded the 2,6-di-O-trityl derivative, whereas both the 2,6- and 3,6-ditrityl ethers were isolated in the case of [Pg.237]

Y. E. Tsvetkov, P. I. Kitov, L. V. Backinowsky, and N. K. Kochetkov, Highly regioselective glycosylation of a secondary position in sugar primary-secondary ditrityl ethers, J. Carbohydr. Chem., 15 (1996) 1027-1050. 

The third process consists of converting methyl D-arabofuranosides (ct(3 mixture) into the 3,5-ditrityl ether (XXII) by treatment with trityl chloride in pyridine, from which by methylation and subsequent detri-tylation and hydrolysis, 2-methyl-D-arabinose was obtained.28 The product gave D-arabinose phenylosazone on treatment with phenyl-hydrazine acetate. 

A l,6-ditrityl-2,3,4,5-dibenzylidene-dulcitol (m. p. 233-234°), prepared by Wolfrom, Burke and Waisbrot9 from 1,6-ditrityl-dulcitol and benzaldehyde in the presence of zinc chloride at room temperature, resembled, as might be expected, the ditrityl ether (m. p. 240-242°) derived from the higher-melting (m. p. 173-174°) 2,3,4,5-dibenzylidene-dulcitol reported above. 

C. Miscellaneous Methods a)Reaction with hydriodic acid (p342) b) Reaction with ammonium hexanitrocerate reagent (p343) c) Precipitation with silico-tungstic or phosphomolybdic acid (p344) and d) Determination as the ditrityl ether (p345)... 

A systematic examination of the tritylation of pentoses by Zeile and Kruckenberg resulted in the isolation of ditrityl ethers of D-xylose and... 

In 1931, Hockett and Hudson reported that pentosides without primary hydroxyls reacted with trityl chloride in pyridine. In later papers, these authors described the preparation of a monotrityl ether of methyl a-L-fucopyranoside (IV), and of derivatives of the mono and ditrityl ethers of methyl /3-D-xylopyranoside (V). 

This type of reaction has also been successful in more complicated instances. For example, methyl /3-cellobioside was converted to the 6,6 -ditrityl ether (XXXIII), the latter was acetylated (XXXIV), then detritylated (XXXV). The two primary hydroxyl groups were then esterified (XXXVI) with p-toluenesulfonyl chloride in pyridine and the ditosyl ester was converted to the diiodide (XXXVII) by treatment with... 

Bredereck and coworkers also studied the 1,6-ditrityl ether, and definite proof of its structure was afforded by an outstanding series of experiments. The amorphous material (m.p. 94r-96°) was treated with the ordinary acetylation mixture, and yielded 3,4,5-tri-O-acetyl-l,6-di-O-trityl-fce(o-D-fructose. Preparation of the oxime followed by further acetylation gave the crystalline acetate of the oxime [ m.p. 207-208° Ca ]D - -118° (in chloroform)]. < The oxime of l,6-di-t>-trityl-D-fructose affords the same product on acetylation. The keto form was proved by formation of the crystalline diethyl dithioacetal from the acetyl derivative. 

Another crystalline material (m.p. 165°), probably the furanoid form, was obtained when sodium acetate and acetic anhydride were used for acetylation of 1,6-di-O-trityl-D-fructose, and treatment of the product with hydroxylamine resulted in splitting of one acetyl group. A monotrityl (m.p. 150-153°) and a ditrityl ether (m.p. 221-226°) were prepared from... 

For the preparation of glycerol ditrityl ether (m.p. 170-171° presumably the 1,3-diether), glycerol (1 g) is heated with triphenylmethyl chloride (7 g) in pyridine (20 ml) for 30 min on the water-bath. Working up is as described above. 

Reduction of 3-ketosucrose with sodium borohydride gives mainly a-D-allopyranosyl-jS-D-fructofuranoside, and deuterium can be incorporated by this approach. Various derivatives of the disaccharide were prepared, including the 6,1, 6-tritrityl ether, the 6,6-ditrityl ether, the penta-acetate, and the hexa-acetate derivable from these, and the 6,6-dichloro-6,6-dideoxy-compound, ... 

In the area of non-reducing disaccharides it has been found that treatment of 2,3,4,6-tetra-0-benzyl-D-gluco5e, -D-mannose, and -D-galactose with trifluoro-acetic anhydride in DMF gives the a,a- and a,/3-dimers in the ratio 2 1 (the method can also be applied to give heterodisaccharides).0 ,o -Trehalose has been converted by way of the 6,6 -ditrityl ether and its hexa-acetate into the... 

Figure 10.5. Ditrityl ether (stereographic projection). The hydrogens have been deieted for clarity.

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