Hydrazine hydrochloride

Prepare a solution of phenylhydrazine by dissolving 1 0 g. of phenyl-hydrazine hydrochloride and 1 5 g. of crystallised sodium acetate in 10 ml. of water if the resulting solution is turbid, filter. Add a solution of 0 5 ml. of cycZohexanone in 8 ml. of water to the reagent... 

Sanofi-Synthelabo researchers discovered pyrazole 53 and analogs to have potent Cannabinoid receptor-1 (CB-1) antagonist/inverse agonist activity and have progressed 53 into development for treatment of obesity and alcohol dependence. The synthesis of 53 was accomplished by heating the diketone sodium salt 51 with the aryl hydrazine hydrochloride in acetic acid to provide the intermediate 52, which was further derivatized... 

Hanus recommends that )S-naphthyl hydrazine hydrochloride should be added to the solution of vanillin in such pioportion that from two to three parts are present for each part of vanillin. After standing for five hours the precipitate is transferred to a tared filter, washed with hot water until the washings no longer precipitate silver nitrate, dried at 90° and weighed. The weight of the hydrazine formed, divided by 1-92 gives that of the vanillin present. This method is avaUable in all cases where an aqueous solution of the vanillin can be prepared. 

For many years such media have been based on strong salt solutions, e.g. calcium chloride brines. Sodium dichromate has been used (seep. 17 26), but recently other inhibitors have been claimed to be effective. One patent quotes N-alkyl-substituted alkanolamines, e.g. 2-ethyl ethanolamine -I- BTA at pH A mixture of hydrazine hydrochloride -i- BTA has been claimed as well as a mixture of gelatin -h triethanolamine -h potassium dihydrogen phosphate . Other examples are to be found in the patent literature and the above are quoted to illustrate the diversity of chemicals that may be used. 

HKsym.-DllfF.THYT.HYDRAZINE HYDROCHLORIDE, 16, 22 Dimethyl malonate, 13, 100... 

Nitrilo-Trimethyl Phosphonic Acid Hydrazine Hydrochloride... 

A corrosion-resistant formulation [1767] is achieved by adding phosphonic acid and hydrazine hydrochloride, as shown in Table 18-3. Hydrazine hydrochloride, combined with nitrilo-trimethyl phosphonic acid, provides a synergetic effect of increased inhibition of the plugging solution. 

The hydrazine hydrochloride can bind the free oxygen present in the plugging solution. It also reduces the amount of sulfur oxides in the cement rock formed after hardening, thus preventing corrosion. The plugging rock has an increased corrosion stability in hydrogen sulfide-containing media. The... 

Plugging Portland cement Nitrilo-trimethyl phosphonic acid Hydrazine hydrochloride Water 73.20-73.38 0.02-0.04 0.18-0.32 up to 100... 

P. F. Tsytsymushkin, S. R. Khajrullin, A. P. Tamavskij, P. V. Kovalenko, Z. N. Kudryashova, R. M. Iskhakov, V. N. Levshin, and V. M. Sudakov. Plugging solution for oil and gas wells—contains plugging Portland cement, nitrilo-trimethyl phosphonic acid, hydrazine hydrochloride and water and has corrosion-protective properties. Patent RU 2(X)2037-C,... 

Whilst anhydrous hydrazine is reported124) to give products of nucleophilic ring opening and cyclization (7 62/7 63) with diphenyl cyclopropenone, hydrazine hydrochloride yielded the azine 16112s ... 

The groups of Giacomelli and Taddei have developed a rapid solution-phase protocol for the synthesis of 1,4,5-trisubstituted pyrazole libraries (Scheme 6.194) [356]. The transformations involved the cyclization of a monosubstituted hydrazine with an enamino-/8-ketoester derived from a /8-ketoester and N,N-dimethylformamide dimethyl acetal (DMFDMA). The sites for molecular diversity in this approach are the substituents on the hydrazine (R3) and on the starting j3-keto ester (R1, R2). Subjecting a solution of the /8-keto ester in DMFDMA as solvent to 5 min of microwave irradiation (domestic oven) led to full and clean conversion to the corresponding enamine. After evaporation of the excess DMFDMA, ethanol was added to the crude reaction mixture followed by 1 equivalent of the hydrazine hydrochloride and 1.5 equivalents of triethylamine base. Further microwave irradiation for 8 min provided - after purification by filtration through a short silica gel column - the desired pyrazoles in >90% purity. 

Organochlorine or -bromine compounds are burned in the presence of aqueous solutions of arsenious oxide (AS2O3) or hydrazine hydrochloride (N2H4.2HCI). These solutions are effective in reducing the elemental chlorine or bromine formed to the chloride or bromide ions according to the reactions (X = Cl, Br) [61,62,64-66] ... 

Preparative scale reduction of nitramines and nitrosamines in acid solution is a convenient route to substituted hydrazines. Early workers used a cathode of tinned copper [120], More recently mercury has been employed as cathode material, although tin would probably be equally suitable. Nitrosamines are conveniently reduced in dilute hydrochloric acid and evaporation of the electrolyte at the end of the reaction affords the hydrazine hydrochloride [121]. Some nitroso compounds are unstable to these acidic conditions. In the case of N-nitrosoindoles, this problem has been overcome in an ingenious manner [122]. The nitroso compound and aqueous sulphuric acid are mixed just prior to reaction and then forced through a porous cathode of bronze coated with mercury at such a rate that the reduction is completed in one pass through the cathode. Other workers have overcome the instability of N-benzyl-N-nitrosoanthraniiic acid towards acid by working in an acetate buffer at below room temperature [123],... 

All initiators are potentially explosive compounds and must be stored and handled with care. 2,2 -AIBN is obtained from the reaction of acetone with potassium cyanide and hydrazine hydrochloride. As shown in equation 17.51, the reaction produces hydrogen cyanide and hydrazine. The latter reacts with acetone forming acetone dihydrazone, which reacts with... 

Hydrazine hydrochloride is used to prepare other hydrazine derivatives. 

Hydrazine hydrochloride is prepared by the reaction of hydrazine with hydrogen chloride. 

Hydrazine hydrochloride is moderately toxic by all routes of exposure. The oral LD50 in mice is 126 mg/kg. 

The metal ion in higher oxidation states can be reduced by most common reducing agents, such as, sulfur dioxide, carbon monoxide, ferrocyanide ion, hydrazine hydrochloride, and hydroxylamine hydrochloride to form Pu3+ (or Pu4+) ions in solution. 

An acidic solution of tellurium (IV) or tellurium (VI) is treated with sulfur dioxide and hydrazine hydrochloride. Tellurium precipitated from solution can be estimated by gravimetry. Selenium interferes with this test. A volumetric test involves converting tellurium to tellurous acid and oxidizing the acid with excess ceric sulfate in hot sulfuric acid in the presence of Cr3+ ion as catalyst. The excess ceric sulfate is measured by titration with a standard solution of ferrous ammonium sulfate. 

In a later report, Mojzych and Rykowski showed that pyrazolo[4,3-< ][l,2,4]triazine 5 could be obtained using a condensation between hydrazine hydrochloride and 5-acetyl-3-(methylsulfanyl)-l,2,4-triazine (Scheme 62). When 1 rather than 2 equiv of hydrazine hydrochloride was used, and the reaction temperature was kept at room temperature, azine intermediate 86 was isolated <2003PJC1797>. 

Reaction of 160 with hydrazine affords the hydrazino derivative 161, which reacts further with hydrazine to yield the pyrazolo [3,4-d] pyrimidine derivative 162. Reaction with hydrazine hydrochloride afforded 163, which was converted into 162 upon treatment with hydrazine (79JHC1109). 

To an ice-cooled (0°C to-—10°C) stirred flask containing 300 ml of water and 55.5 ml of concentrated hydrochloric acid is added dropwise over a 10 min period 33.5 gm (0.31 mole) of freshly distilled phenylhydrazine. Phenyl-hydrazine hydrochloride crystals precipitate as they are formed. Addition of... 

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