Hydrazines cyanoethylation

Protective group for nucleosides. Stepwise synthesis of oligonucleotides utilizing 2-cyanoethyl phosphate (1, 172-173) requires protection of the 3 -hydroxyl group which can be cleaved under essentially neutral conditions, since a methoxy-trityl ether is sensitive to acid and a /3-cyanoethyl phosphoric ester is sensitive to alkali. The /3-benzoylpropionyl group meets these requirements, since it is quantitatively cleaved by dilute solutions of hydrazine hydrate in pyridine-acetic acid. The esters are prepared by condensation with DCC (dicyclohexylcarbodiimide). Definitive paper R. L. Letsinger and P. S. Miller, Am. Soc., 91, 3356 (1969)... 

Amidooximation of cyanoethylated starch is relevant here. The reaction of (cyanoethyl)starch with hydroxylamine at pH 7.1 and a temperature of 90 °C for 90 min produced a material used to chelate Fe(III) and A1 cations.2640 By reacting starch dialdehyde with acrylonitrile and hydrazine in alkaline solution, followed by adjusting the pH to 5-6 a glue was prepared.2641... 

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