Hydrolysis osazones

Phenylhydrazine is, however, frequently supplied in the form of its hydro chloride or sulphate, since these salts on exposure to light darken less rapidly than the free base. If these salts are used, however, osazone formation is unsatisfactory, partly because the mineral acid formed by hydrolysis of... 

Chemical Synthesis. The first synthesis of ascorbic acid was reported ia 1933 by Reichsteia and co-workers (14,39—42) (Fig. 4). Similar, iadependent reports pubHshed by Haworth and co-workers followed shordy after this work (13,43—45). L-Xylose (16) was converted by way of its osazone (17) iato L-xylosone (18), which reacted with hydrogen cyanide forming L-xylonitfile (19). L-Xylonitfile cyclized under mild conditions to the cycloimine of L-ascorbic acid. Hydrolysis of the cycloimine yielded L-ascorbic acid. The yield for the conversion of L-xylosone to L-ascorbic acid was ca 40%. 

The unsaturated diamine, CgHgoNj, from the hydrolysis of sphero-physine, on oxidation with permanganate yields the ketoaldehyde, McgCH. CO. CHO fdioxime, m.p. 95-6°, and osazone, m.p. 113-4°) and putrescine, NH2[CH2]4NH2, which indicates that this unsaturated diamine is Me2CH. CH CH. NH[CH2]4. NH2. 

Lactosone was first prepared by the hydrochloric acid decomposition of the phenylosazone,1 although it had been noted that, in acid solutions, lactose phenylosazone forms an anhydride.197 Since its discovery,17 the benzaldehyde method has usually been employed,6-10-28 because it avoids the risks of osone hydrolysis and of alteration to the osazone. Lactosone is hydrolyzed by hot, dilute, mineral acid to D-glucosone and D-galactose.1-6 It reacts with cyanide to form an analog of iminoascorbic acid which, on acid treatment, is converted into a mixture of D-glucoascorbic acid and D-galactose.10... 

Hydrolysis of the diacetamides is effected by acids. Dilute hydrochloric, sulfuric and nitric acid have been used. An aldose with one carbon atom less than the original nitrile is then liberated from the combination. Only exceptionally can this aldose be isolated in pure condition without transforming it into an insoluble derivative in these instances, the method has been employed for preparative work. In most cases the sugar has been characterized as an osazone. The aldose, without great purification, has been employed successfully for reduction - or oxidation experiments. ... 

L-fhreo-Pentos-2-ulose (9) was prepared by several procedures (see Scheme 3). In procedure A, D-galacturonic acid (14) was reduced with sodium amalgam to L-galactonic acid (15), which lactonized to L-ga-lactono-1,4-lactone (16) by removal of water. Treatment of 16 with ammonia in methanol afforded L-galactonamide (17) which, on oxidation with sodium hypochlorite, gave L-lyxose (18). Reaction of 18 with phenylhydrazine yielded the corresponding osazone (19) which, on hydrolysis, afforded 9. 

In procedure B, a similar method was followed. D-Glucaro-1,4 6,3-dilactone (20) was reduced to L-gulono-1,4-lactone (21) which, when treated with ammonia in methanol, afforded L-gulonamide (22). Oxidation of 22 with sodium hypochlorite gave L-xylose (23), which formed osazone 19 with phenylhydrazine. Hydrolysis of 19 afforded 9. 

Watters, Hockett and Hudson1 have prepared a non-crystalline monomethylmannose which forms an osazone with the same properties as those of 6-methyl-n-glucosazone. The synthesis was achieved by methylation of methyl 2,3,4-triacetyl-a-D-mannopyranoside, followed by hydrolysis. Schmidt and Heiss,13 studying the epimerization of 6-methyl-D-gluconic acid, have claimed to have isolated the phenyl-hydrazide of 6-methyl-n-mannonic acid. 

Degradation of beet arabinan and yeast mannan afforded osazones which, on hydrolysis in ethanolic solution with a cationic exchange resin in the acid state, yielded arabinose and a mannobiose, respectively, together with glycerosazone. These results, and also the nitrogen content of the polymeric materials recovered after Barry degradations, show that... 

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