P-Nitrophenyl glycosides

M sodium chloride p-nitrophenyl glycosides of chitin oligosaccharides 92... 

The application of diazo coupling is somewhat limited by the availability of the p-aminophenyl glycosides, particularly of those of the oligosaccharides. Their precursors, the p-nitrophenyl glycosides, are usually obtained by the condensation of a per-O-acetylated glycosyl halide with p-nitrophenol in ethanol (Michael reaction)19,20 or by the reaction of a per-O-acetylated sugar with p-nitrophenol in the presence of a Lewis acid catalyst (Helferich reaction).21 p-Nitrobenzyl 1-thioglycosides have also been prepared by the condensation of the... 

For further data, see Refs. 367, 483, and 631. 6 Ref. 435 states syrup, [a]D —88° (E) evidently, an impure sample. c Ref. 775 states syrup, [a]D -33.1° (E), for a product of the alkaline treatment of the p-nitrophenyl glycoside its structure is probably quite different. d Ref. 632 states crystalline, hydroscopic compound, without, however, any m.p. value. e In the original paper,746 the opposite sign (printer s error) appeared (see also, the acetate479,746). r Obtained by sublimation of the lower-melting modification at 85—100°. [a]D —9° was given by mistake. 

The existence of a linear free energy relationship between two enzymes acting on the same library of substrates can give an indication of common mechanism. Thus, a plot of log(kcat/Ani) for hydrolysis of a series of p-nitrophenyl glycosides and aryl glucosides by the GH 1 enzyme from the mesophile Agrobacterium... 

Snyder and Link had investigated the acid hydrolysis of some o- and p-nitrophenyl glycosides (see Table XXVII), and found that the ease of hydrolysis is in the same order as has been found for alkyl glycopyranosides ... 

The acid-catalysed addition of phenol to 3,4,6-tri-O-acetyl-D-galactal afforded phenyl 3,4,6-tri-0-acetyl-2-deoxy-0 -D-/yxo-hexopyranoside which was nitrated with nitric acid in a mixture of acetic acid and acetic anhydride to give the p-nitrophenyl glycoside. ... 

---