Methyl 2,4-di-O-

It has recently been reported21 that a mixed osazone of 3,4-di-O-methyl-D-glucose can be converted, by treatment with p-nitrobenzaldehyde, into an osone which reacts with phenylhydrazine to give 3,4-di-O-methyl-D-glucose phenylosazone. Von Lebedev29 claimed to have obtained D-glu-cosone 6-phosphate, isolated as an amorphous lead salt, by the action of hydrochloric acid on the phenylosazone prepared from D-fructose 6-phosphate. 

The methyl-substitution pattern of the neutral sugar residues can be reliably identified from their mass spectra.41-43 Identification of the substitution pattern from the electron-impact, mass spectra rarely presents any major problems. It should, however, be noted that, in some cases, the occurrence of symmetrical molecules jeopardizes the identification. An example of this is the symmetrical, 3,4-di-O-methyl derivative (6) of mannose, which is commonly found in the analysis of... 

Analysis of Freshly Cyclized 2,3-di-O-methyl-D-arabinose. The system 3,4-di-O-methyl-D-mannitol (2)—sodium metaperiodate meets the foregoing specifications. 3,4-Di-O-methylmannitol was rapidly cleaved by periodate to 2,3-di-O-methyl-D-arabinose (3), which is resistant to further oxidation (19). We prepared the crystalline / -anomer of this sugar (the a-anomer had previously been crystallized (20)) and showed that on a suitable GLC column the trimethylsilyl derivatives of the four ring forms could be separated (Figure 9). The individual peaks were characterized by preparative GLC and mass spectrometry. This allowed the analysis of the mixtures of anomeric forms generated in kinetic experiments (see p. 34). 

Methyl 6-deoxy-2,3-0-isopropylidene-4-0-tosyl-L-mannoside Methyl 0-deoxy-2,3-O-isopropyIidene-5-O-tosyl-L-mannoside Methyl 0-deoxy-2,3-di-O-methyl-4-O-to9yl- -L-mannoside Methyl 4,0-O-benzylidene-2-O-methyl-3-O-tosyl- 8-n-gaIactoside Methyl 0-deoxy-3-O-methyl-2,4-di-0-tosyl- 8-D-galactoside Methyl 0-deoxy-3,4-di-O-methyl-2-O-tosyl-acL-galactoside Methyl 2,0-dideoxy-3-O-methyl-4-O-tosyl-a-D- galactoside ... 

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