From hydrazines

Hydrazine hydrate of 60 per cent, and 100 per cent, are available commercially. The preparation from hydrazine sulphate is hardly worth while. 

The reaction represented is that with hydrazine solution, produced from hydrazine sulphate and sodium acetate in the presence of aqueous alcohol. Excellent results are also obtained by interaction of the commercially available 60-64 per cent, hydrazine solution with a solution of 2 4 dinitrochloro-benzene in triethylene glycol or in diethylene glycol at about 20°. 

Dimethylpyrazole (III) may be prepared from acetylacetone (I) and hydrazine (II) (produced from hydrazine sulphate and aqueous alkali). The reaction may be represented as ... 

All the sulfonic acid hydrazides are made from hydrazine or semicarbazide and the appropriate sulfonyl chloride in the presence of an HCl acceptor such as ammonia. 

Phenyl-3,6-dihydro-l,3,4-oxadiazin-2-one (50) is a high temperature blowing agent used primarily for polycarbonates (qv). It is prepared by the reaction of a-hydroxyacetophenone and methyl carbazate (52), made from hydrazine and dimethyl carbonate (175) ... 

Agricultural Uses. Pesticides represent the second largest commercial market for hydrazine. Hundreds of hydrazine derivatives have been patented for a wide range of agricultural appHcations. Table 13 presents a sampling of the 50—60 that are commercially available or developmental products. These compounds are made from hydrazine, MMH, and UDMH and are for the most part heterocycHc nitrogen compounds (see Insect control technology). 

Automobile safety air bags use sodium azide [26628-22-8] NaN, for gas generation. It can be made from hydrazine by refluxing ethyl or Abutyl nitrite with hydrazine hydrate and sodium hydroxide in alcohol (209,210) ... 

From Hydrazines and P-Bifunctional Compounds. One of the oldest examples in this class is the reaction of a p-diketone with a substituted hydrazine to give a pyrazole (eq. 1). 

Pyrazolo[3,4-d]pyridazines (555) can be prepared readily from hydrazines and pyrazoles substituted in positions 4 and 5 with an acyl and an ester group, or with two ester groups. 4,5-Pyrazolinediones have been used as starting materials for the synthesis of the quinoxaline derivatives (548) (see above) and of pyrazolo[3,4-e][l,2,4]triazines (556)... 

In a recent review of heterocyclic compounds no further mention is made of the three-membered ring structures for the condensation products from hydrazine and carbonyl compounds. However, the products obtained from azodicarbonyl derivatives with aliphatic diazo compounds were formulated as diaziridines [Eq. (1)]. Recent investi-... 

Propose a mechanism to account for the formation of 3,5-dimethylpyrazole from hydrazine and 2,4-pentanedione. Look carefully to see what has happened to each carbonyl carbon in going from starting material to product. 

Ammonia also may be present as the result of the partial breakdown of amines used for condensate system protection, from hydrazine, or potentially even from nitrate. 

This silyl hydrazone formation-oxidation sequence was originally developed as a practical alternative to the synthesis and oxidation of unsubstituted hydrazones by Myers and Furrow [31]. The formation of hydrazones directly from hydrazine and ketones is invariably complicated by azine formation. In contrast, silyl hydrazones can be formed cleanly from /V,/V -bis(7< rt-butyldimethylsilyl)hydrazine and aldehydes and ketones with nearly complete exclusion of azine formation. The resulting silylhydrazones undergo many of the reactions of conventional hydrazones (Wolff-Kishner reduction, oxidation to diazo intermediate, formation of geminal and vinyl iodides) with equal or greater efficiency. It is also noteworthy that application of hydrazine in this setting may also have led to cleavage of the acetate substituents. 

Acyclic ADC compounds, which are more correctly named as derivatives of diazene, are generally prepared from hydrazine derivatives. For example, diethyl azodicarboxylate (Chemical Abstracts name diethyl diazene-1,2-dicarboxylate)5 is prepared from hydrazine by treatment with ethyl chloro-formate followed by oxidation with chlorine in benzene-water.6 Other oxidants which have been used include JV-bromosuccinimide,7 nitric acid,8 inorganic nitrates,9 potassium dichromate,10 silver carbonate on celite,11 and phenyl iodosotrifluoroacetate.12 The hydrazine derivative may also be... 

Hydrazines react with thiocarbonyl compounds, such as dithioesters, to afford directly symmetrical 1,3,4-thiadiazoles via a dithioacylhydrazine intermediate, which can be isolated and converted to the thiadiazole upon treatment with an electrophilic reagent or under thermal conditions (see Section 5.10.9.1.1). Examples of the direct formation of thiadiazoles from hydrazines and thiocarbonyls can be found in CHEC-II(1996) <1996CHEC-II(4)379>. 

Vilsmeier type reagent 160 was employed in the direct and efficient synthesis of dimethylformamidrazones from hydrazines . 2-Benzotriazolyl-13-dioxolane (161) has been utilized as a novel formyl cation equivalent . 1-... 

Diimide from hydrazine hydrate Diimide can be generated from hydrazine hydrate by oxidation with this hypervalent iodine compound in CH2C12. 

Ethyl hydrazinecarboxylate, from hydrazine hydrate and diethyl carbonate, 51, 121 Ethyl 1-hydroxycyclohexylace-tate, 53, 67... 

Hypercoordinated Silicon Complexes with Ligands Derived from Hydrazine 491... 

The elegant synthesis of sodium azide from hydrazine and alkyl nitrite is carried out in the same way (Stolle) ... 

Mention should also he made of radicles with bivalent nitrogen which are derived from hydrazines, the so-called hydrazyls. They are deeply coloured compounds which are obtained by dehydrogenation of tertiary hydrazines and form equilibrium mixtures with colourless tetrazanes, which dissociate into these free radicles (S. Goldschmidt),... 

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