Hydrazine treatment

During analysis of a series of tris(organosilyl)hydrazines, treatment with 1 1 mixtures of nitric and sulfuric acids had caused explosive reactions [1], Subsequently the hypergolic behaviour of a range of 20 silylhydrazines and congeners... 

It must be remembered that hydrazine treatment of peptides containing allyl-based protecting groups also results in reduction of the aUyl moiety 0 4 this is successfully prevented by adding a 200-fold excess of allyl alcohol as a scavenger.O Moreover, hydrazine treatment of peptides may lead to aspartimide formation in the case of cyclization-prone Asn-Xaa and Asp-Xaa sequences (see Section 2.2.2). 

The Wolff-Kishner reaction is a classical reduction method of ketones to alkanes. This method involves converting the ketone to its corresponding hydrazine treatment of the resulting hydrazine with base affords the alkane and nitrogen gas. Because elevated temperatures (> 200 °C) and strong base are required, this method is harsh when sensitive functionality is present. However, milder methods have been developed including the Myers modification where the reaction temperatures are much lower (s 100 °C). 

The process can be repeated by hydrolysis with hydrazine, treatment with tosylchloride, and reaction again with 3-phthalimidopropyl tosylate to form the tripropylene-tetraamine-type compound as shown on the bottom of the sequence. In this way, polyamines with a few tetramethylene, trimethylene, and ethylene bridges can be constructed. The final products will have terminal tosylamines that can be ring-closed using the Richman-Atkins procedure. It is also possible to convert the terminal tosylamines to the tosylates as shown below (Iwata and Kuzuhara, 1985). 

In those applications, anhydrous hydrazine treatment under mild conditions was... 

A variation of the Suzuki-type coupling reaction provides another means for placing a functionalized carbon atom on to position 17. The sequence starts with conversion of estrone methyl ether to its hydrazide by reaction with hydrazine. Treatment of this intermediate with 1,1,3,3 tetramethylguanidine (TMG) and iodine leads to the 17-enol... 

Aminoalkylquinoxalines (17) have been derived from a-amino acids (10) as shown in Scheme 2, the amino group is protected by formation of a phthalimide derivative (11). The intermediate chloromethyl ketone (12) is converted via a pyridinium salt (13) to a nitrone (14) which on hydrolysis yields the a-dicarbonyl compound (15) required for diamine condensation. Finally the phthalimide residue is removed from the condensation product (16) by hydrazine treatment. ... 

This reaction was first reported by MacDonald and Fischer in 1952. It is the degradation of hexoses into pentoses involving the steps of formation of dithioacetal, oxidation to unsaturated disulfone by means of perphthalic acid, hydrazine treatment, and benzalde-hyde splitting of the corresponding hydrazone. Therefore, the whole process is known as the MacDonald-Fischer degradation. In addition, when the unsaturated disulfone is dissolved in aqueous ammonia or methanol saturated with ammonia, 2-deoxy-2-amino sugar is resolved. This reaction in combination with mass spectroscopy was used to study the structure and stereochemistry of carbohydrates. ... 

Beginning in 1999, Kiebooms and Wudl reported the production of isothianaphthene analogs as shown in Scheme 12.29 [168]. After the removal of lower My, fractions by Soxhlet extraction with methanol and THF, polymer 124a was isolated as a purple solid that was found to be only soluble in 1,1,2,2-tetrachloroethane. It was found that the initially isolated material was partially doped, but could be dedoped by conventional hydrazine treatment. From the absorption onset of solvent cast films, the Eg was determined to be 1.2-1.5 eV [168,169]. Characterization of the IRAV modes correlated with the generation of charge within the doped polymer revealed sharp bands of quite low intensity, indicative of strongly localized charge carriers [98,169]. 

As part of their studies, Bruening and coworkers [15] examined the effects of common etching procedures on the work function of CdSe. They observed that the bromine/methanol etch increases the work function while a subsequent hydrazine treatment then reduces it. Because the bromine/methanol etch leaves an elemental Se residue on the surface, the authors suggest that the higher work function of Se relative to CdSe may account for the increase in work function. They noted that such etching effects lead to ir-reproducible surfaces and can produce substantial variations in adsorption properties [15]. 

If hydrazine treatment is carried out in presence of 1.5M NaCl, only C residues react well. The following piperidine treatment will therefore destroy glycosidic bonds before only C. Following fragments will be created. 

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