Hydrazine dihydrochloride

Hydrazine dihydrochloride [5341-61-7] M 105.0, m 198 , d 1.42. Crystd from aqueous EtOH and dried under vacuum over CaS04. 

Reaction of diacylfuroxans with hydrazine dihydrochloride gave furoxano-pyridazines (55JA4233, 77MI2, 99KGS1259), whereas treatment with hydrazine hydrate in acetic acid afforded furazanopyridazines (Scheme 63) (92JHC87). 

Microwave irradiation of a reaction mixture containing aromatic nitriles, hydrazine hydrate, hydrazine dihydrochloride, and ethylene glycol as solvent in a one-pot process gave 3,5-disubstituted 4-amino-l,2,4-triazoles 98a-i in excellent yields (Equation 35 and Table 14) <2000TL1539>. 

A number of symmetrically 3,5-disubstituted 4-amino-1,2,4-triazoles were able to be rapidly synthesised via focussed microwave heating, by the reaction of aromatic nitriles with excess hydrazine hydrate in ethylene glycol, in the presence of hydrazine dihydrochloride (Scheme 3.21)37. 

Oxadiazoles have often attracted the attention of medicinal chemists as stable bioiso-steres of metabolically labile esters. 1,3,4-Oxadiazoles are generally prepared by cyclodehydration of 1,2-diacylhydrazines or their equivalents. Symmetrical 2,5-disubstituted examples were able to be rapidly prepared in a one-pot condensation-cyclodehydration of benzoic acids (2 equiv) with hydrazine dihydrochloride, in the presence of... 

RECOVERY OF HYDRAZINE RESIDUES AS HYDRAZINE DIHYDROCHLORIDE OR HYDRAZINE SULFATE... 

Preparation of Hydrazine Dihydrochloride from Benzalazine. One hundred and four grams of benzalazine (0.5 mol) is suspended in 400 ml. of water in a 4-1. round-bottom flask, and 80 ml. of concentrated hydrochloric acid added. The suspension is subjected to- steam distillation until no more benzaldehydef comes over in the distillate. 

Hydrazine dihydrochloride, 92 Hydrazine residues, recovery of, 92 Hydrazine sulfate, 90, 92 Hydrazoic acid, 77, 78 Hydriodic acid, 157, 159 by action of iodine on hydrogen sulfide, 157 constant boiling, 158 fuming, 162 stabilization of, 159 Hydrobromic acid, 151, 152, 155 constant boiling, 155... 

Hexamminenickel(II) iodide, 3 194 Hydrates, nomenclature of, 2 264 Hydrazidicarbamide, 4 26 Hydrazine, 1 90 and derivatives, from hydroxyl-amine-O-sulfonic acid, 5 124 derivatives of, by reduction of A -nitrosohydroxylamine-Ar-sulfonates, 6 121 residues, recovery of, 1 92 Hydrazine dihydrochloride, 1 92 Hydrazine urazolate, formation of, in preparation of urazole, 5 53, 54... 

NH2NHCONHNHCONH2 Carbo-hydrazide-A -earhoxamide, 4 36 NH2NH2 Hydrazine, 1 90, 92 NH2NH2-2HC1 Hydrazine dihydrochloride, 1 92... 

With alkylamines, the primary reaction products are aminophosphonium salts, [Ph3PNHR]+Br , which need to be dehydrobrominated with ammonia or sodium amide. In a similar marmer, dichlorotriphenylphosphorane reacts with hydrazine dihydrochloride, at 180-220 °C, to form a bis(phosphorane)diimine after treatment with a strong base (hquid ammonia or potassium teri-butoxide), equation (3). ... 

A series of 2,5-diaryl-l,3,4-oxadiazoles have been synthesized by reacting a mixture of corresponding aromatic acid, hydrazine dihydrochloride and phosphorus pentoxide in orthophosphoric acid under microwave conditions [23]. 

The dihydrochloride may be crystallized by dissolving in boiling absolute ethyl alcohol (i g. requires 20 cc. of alcohol), adding a little concentrated hydrochloric acid and, after cooling slightly, about one-fifth of the volmne of ether. The dimethyl-hydrazine dihydrochloride separates as a white crystalline powder, melting at 165-167°. 

One route to these compounds is the reaction of 3-amino-1,2,4-triazoles (312) with dicyanodiamide (485) to yield (49USP2473797 53JOC1610) 5,1-diamino-l,2,4-triazolo[4,3-a]l,3,5-triazines (486). The 1,3,5-triazine ring of 7-methoxy-3-phenyl-l,2,4-triazolo[4,3-a] 1,3,5-triazine (489) was formed (70T3357) by the direct cyclocondensation of 0-methyl-N-(5-phenyl-l,2,4-triazol-3-yl)urea (488) with methyl diethoxyacetate (487) or triethyl orthoformate. 3,5,7-Triamino-1,2,4-triazolo[4,3-a] 1,3,5-triazine (490) was prepared (53JOC1610 63ZOB1355) in one step by the reaction of two equivalents of dicyanodiamide (485) with one equivalent of hydrazine dihydrochloride. 

Substituted pyrazoles can be prq>ared by the alkylation of a-(dimethylamino)nitriles with bromodi-ethyl acetal followed by heating with hydrazine dihydrochloride in ethanol. 3,5-Dialkylpyrazoles were... 

Nagata and Itazaki " developed a procedure for the reduction of the highly hindered 11-ketosteroids not requiring anhydrous hydrazine. The ketone (1 m.) is heated with 66 moles of hydrazine hydrate, 8 moles of hydrazine dihydrochloride, and 150 moles of triethylene glycol at 130° for 2.5 hrs. Potassium hydroxide (22 m.) is added as pellets, the temperature is gradually raised to 210° (distillation of hydrazine-water) and held for 2.5 hrs. yield 90%. 

Reaction of 5,6-bis( crf-butylsulfanyl)-l-[2,3-bis(/erf-butylsulfanyl)cyclopropenylium]calicene perchlorate with an equimolar amount of hydrazine dihydrochloride in dichloromethane in the presence of triethylamine at — 78 "C afforded 3,8-bis( crr-butylsulfanyl)-5,6-diazatetracyclo [8.3.0.0. 0 ]trideca-l,3,6,8,10,12-hexaene (8) as a pale yellow solid in 43% yield. ... 

The three toxins are hydrazine dihydrochloride, a-naphtyl-isothiocyanate (ANIT) and butylated hydroxytouluen (BHT), all of which are well-known and well-studied toxins. The same data have previously been analysed by Antti et al.20 using batch analysis and the results obtained with the Tucker3 analysis are compared with the results of the batch analysis. 

---