Altropyranoside deamination

As might be expected, the nitrous acid deamination of methyl 2-amino-4,6-0-benzylidene-2-deoxy-a-D-altropyranoside (10) hydrochloride leads45,46 uniquely to methyl 2,3-anhydro-4,6-0-benzylidene-a-D-allopyranoside (11). The benzylidene group does not play an... 

The deamination of methyl 3-amino-3-deoxy-/3-D-altropyranoside was studied in 1934, but the products were not fully characterized.14411 The syrupy product was converted into a methylated derivative that had an elemental analysis corresponding to that calculated for a methyl tetramethylhexoside. The conditions used for methyl-ation would have opened an epoxide ring. Methyl 2,3-anhydro-4,6-0-benzylidene-a-D-mannopyranoside precipitated quantitatively from solution when the corresponding 3-amino-3-deoxyaltroside derivative was deaminated in aqueous medium.145 Epoxide formation was likewise reported to be quantitative in the deamination of the analogous 2-amino-2-deoxyaltroside.83 145 On deamination, 4-amino-l,6-anhydro-4-deoxy-/3-D-mannopyranose also gave an epoxide, namely, 1,6 2,3-dianhydro-/3-D-talopyranose, in unspecified yield.146... 

---