Aldonic acids hydrazides

Compounds 312 were also prepared by alternative routes that comprised cyclocondensation of aldonolactones (313) with 1-hydrazinophthalazines or aldonic acid hydrazides (315) with 1-chlorophthalazines. Their acetates 316 were obtained by direct acetylation of 312 or by condensation of aldonoyl chloride acetates (38) with 1-hydrazinophthalazines (90MI6) (Scheme 96). l,2,4-Triazolo[3,4-a]phthalazin-3-yl acyclo C-nucleosides derived from reducing disaccharides were similarly prepared (90MI2). 

Aldonic acids form crystalline esters, amides, hydrazides, and benzimidazoles. Many of these derivatives, as well as the lactones, have been valuable... 

Isolation of Aldonic Acid Lactones through their Hydrazides, Alva Thompson and M. L. Wolfrom,/. Amer. Chem. Soc., 68, 1509-1510 (1946). 

The aldonic acids are the initial oxidation products produced from aldoses by most oxidants and are usually isolated as the metallic salts or the lactones. As a result of the ease with which the crystalline lactones, salts, amides, hydrazides, and other derivatives can be formed, aldonic acids are... 

Normally the alkali salts of the aldonic acids are slightly more dextrorotatory than the free acids, when the hydroxyl of carbon 2 lies on the right 23). This correlation might be considered to be an extension of the hydrazide rule. The lead salts present an exception, apparently because a complex is formed between the lead ion and the hydroxyl on carbon 2 24)- The lead salts are acidic in contrast to the normal type. The rotatory displacement in relation to the calcium salts is levorotatory when the hydroxyl of carbon 2 is on the right. 

The salts and lactones of the aldonic and saccharic acids react readily with phenylhydrazine to form the hydrazides 48) The low solubility and ease of crystallization of the hydrazides have led to their use for the characterization and isolation of the acids. Aniline reacts in a manner similar to phenylhydrazine. 

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