5-Hydrazino-3-phenyl Hydrazin

Aryl-tetrazole liefern mit 2-Benzyliden-l-chlorcarbonyl-l-phenyl-hydrazin 5-Aryl-2-(2-benzyliden-1 -phenyl-hydrazino)- , 3,4-oxadiazole547. 

Reactions of 2-benzoselenopyrylium salts 74 with methyl- or phenyl-hydrazine afforded the 1 -hydrazino-1 //-isoselenochromenes, while the treatment of the selenopyrylium salts 74 with anhydrous hydrazine in dry MeCN resulted in a ring transformation to give the 5/7-2,3-diazepines 75 in the one-pot reaction under mild conditions in moderate yields <2005CPB60> (Equation 9). 

Derivatives of the amino acid type in which phenyl hydrazine, as an amjne, is substituted for a hydrogen atom of the hydrocarbon radical of an acid. They are known as hydrazino acidSy e.g. ... 

Heptatriensaure-nitril und Phenyl-hydrazin ergeben 5-Amino-3-(3-butenyl)-l-phenyl-lH-pyrazol (96%) 2-Hydrazino-pyridin und Butadiensaure-nitrile werden zu 3-Alkyl-5-amino-l-(2-pyridy I )-lH-pyrazolen ( 90%) umgesetzt625. 

Beim Erhitzen des 1,3-Thiazols i mit Phenyl-hydrazin wird unter Verbrauch von zwei Mol Phenyl-hydrazin das entsprechende 5-(2-Phenyl-hydrazino)-lH-pyrazol erhalten1030 ... 

Bis-[trifluor-acetyl]-l-dimethylamino-naphthalin erleidet mit Hydrazinen einen nukleophi-len Stickstoff-Austausch der Dimethylamino-Gruppe am Aren durch die Hydrazino-Funktion, gcfolgt von einer Cyclokondensation zu 5-(Trifluor-ac,ciyl)-i-trifluormethyl- ILf-(benzo g]inda-zol) (mit Hydrazin) bzw. 2-Phenyl-5-(trifiuor-acetyl)-3-trifluormelhyl-2H-(benzo g indazoi) [mit Phenyl-hydrazin 100% Schmp. 154-155° (Hexan/Benzol)]681 ... 

Eine Erweiterung der Reaktionsmoglichkeiten stellt der Einsatz von Natrium-hydra-zid/Hydrazin dar, das 1-Aryl-l -alkene zu den entsprechenden Aryl-alkanen reduziert. So erhalt man bei der Reduktion von rrans-Stilben in Benzol 96% d.Th. 1,2-Diphenyl-athan6 7, als Nebenprodukt fallt /-Phenyl-2-(2-hydrazino-phenyl)-dthan1 an. 

Bloink and Pausacker suggested a mechanism similar to that of Braude and Forbes, in which the hydrazonium salt, instead of oxidizing the hydroxyl group, oxidizes the hydrazino hydrazone formed by the action of phenyl hydrazine on the phenylhydrazone by way of (7). The hydrazino hydrazone is also an intermediate in the Weygand scheme B (see p. 145) for ketoses, where it is produced by an Amadori rearrangement. 

An additional heterocyclic ring fused to a (6 5 6) system can be constructed by a cyclocondensation reaction of an appropriately substituted tricyclic derivative with an external reagent. The NH2-CN functionality of (177) was transformed into a pyrimidine by the reaction with formamide <91H(32)895>, and cyclocondensation of the Ac-OH functionality in (178) with phenyl-hydrazine gave a pyrazole <9lH(32)90l>. A hydrazino derivative (179) was condensed with a carboxylic acid to give a 1,2,4-triazole in the reaction that involves an N-2 atom of (179) <88Ci(L)785>. 

The specificity of the response was not directed solely against the hydrazino-group as compounds such as phenyl-hydrazine did not cross-react. 

The methoxy group is replaced in the reaction of 3-methoxy-5-phenyl-1,2,4-triazine 1-oxide 46 with ammonia, resulting in 3-amino-5-phenyl-1,2,4-triazine 1-oxide 47. The treatment of 3-methoxy-1,2,4-triazine 1-oxide 20 with hydrazine leads to 3-hydrazino-1,2,4-triazine 1-oxide 48 (71JOC787). 

The free selenazole hydrazines are solids, sometimes well crystallized compounds. They show the typical properties of hydrazines. Thus they reduce Fehling s solution on warming and liberate silver, even in the cold, from ammoniacal silver nitrate solution. Further, they react with carbonyl compounds for example, benzylidene hydrazones are formed with benzaldehyde. These are identical with the hydrazones formed by direct condensation from benzaldehyde selenosemicarbazone and the corresponding a-halogenocarbonyl compound. 2-Hydrazino-4-phenylselenazole has also been reacted with acetophenone. The 2-a-methylbenzylidenehydrazone of 4-phenyl-selenazole (2, K = CJl, R" = H, R" = NH—N CMe-aH ) forms golden yellow plates mp 171°C. ... 

Hydrazone of 1 -hydrazino-1 -hydroxy-4-phenyl-1,2-dihydro-3//-pyrido [l,2-c]pyrimidin-3-one was patented as cross-linkers for making physiologically compatible and H2O insoluble hydrazine or hydrazono compounds (97JAP(K)97/59303). 

The parent heterocycle of pyrido[2,3-e][l,2,4]triazine and its phenyl derivative 39 were prepared (89JHC475) by cyclization with polyphos-phoric acid of 3-acyIhydrazino-2-aminopyridines 36, obtained by reduction of the corresponding 3-acylhydrazino-2-nitropyridines 35. Compounds 35 were obtained from 3-fluoro-2-nitropyridine 34 either by reaction with benzoylhydrazine or by reaction with hydrazine and subsequent for-mylation of the initially formed 3-hydrazino-2-nitropyridine 38. Attempts to prepare 38 from 3-chloro-2-nitropyridine gave 2-hydrazino-3-chloropyridine 37. These results could be explained by semiempirical calculations (CNDO and MNDO calculations). 

Quite similarly, the reaction product obtained from 2-benzylthio-3-phenylquinazolin-4(3H)-thione and hydrazine should be assigned the structure 2-anilino-3-aminoquinazoline-4(3//)-hydrazone instead of the reported 2-hydrazino-3-phenyl quinazoline-4(3//)hydrazone (Scheme III.23) (70IJC1055). 

It was reported that 7-chloro-3-phenyl-4H-pyridazino[6,1 -c ]-1,2,4-triazine underwent reaction with hydrazine to give the unexpected product (146) (69AC(R)552). However, it was later established that the assigned structure for this reaction product was incorrect, and the correct hydrazino structure (147) for this product was confirmed by an independent synthesis (70S180). 

DMQPH = 6,7-dimethoxy-l-methyl-2(177j-quinoxalinone-3-proprionylcarboxylic acid hydrazide, HCPI = 2-(4-hydrazinocarbonylphenyl)-4,5-diphenyli-midazole, DBPM = 7V-[4 (6 dimethylamino-2-benzofuranyl)phenyl]maleimide, DNS-H = dansyl hydrazine, DBD H = 4 (AA -dimethylaminosulphonyl) 7-hydrazino-2,l,3-benzoxadiazole, DETBA = l,3-diethyl-2-thiobarbituric acid, DCIA = 7-dimethylamino-3- 4-[(iodoacetyl)amino]phenyl -4-methylcou marin, m-CED = 1, 2-bjs(3-chlorophenyl)ethylenediamine. 

Synthesis of 4-amino-2-pyrazolin-5-ones is usually achieved by treatment of an a-amido-/3-aldehydo- or /9-ketoester with hydrazines according to the classical method for preparation of 2-pyrazolin-5-ones. Variants on this procedure consist of using an a-amidoester which has /9-substituents whose reaction is equivalent to that of a /9-carbonyl substituent. Such compounds are D-benzylpenicilloic acid a-methyl ester,1027 ethyl phenylpenaldate243 and the acetal of an a-amido-/9-formyl ester.59,243 Cornforth has isomerized 2-phenyl-4-hydrazino-methylidyneoxazolidone to 4-benzamido-2-pyrazolin-5-one. The same compound was obtained by treatment of 1-ethoxyvinyl-2-phenyl-oxazolidone with phenylhydrazine.319... 

Phenyl-hydrazino)-malonsaure-amid-nitril liefert mit Hydrazin-Hydrat ohne Losungsmittcl auf dem Wasserbad 3(5)-Amino-5(3)-hydroxy-4-phenylazo-1 H-pyrazol (95% Schmp. 238°)724. 

Mit (2-Chlor-6-phenyl-3,4-dihydro-pyrimidin-4-yliden)-malonsaure-dinitril ist die direkte Umsetzung mit Hydrazin ebenfalls moglich, wobei gleichzeitig Halogen-Substitution erfolgt443 und man erhalt 3,5-Diami-no-4- (2-hydrazino-6-phenyl-4-pyrimidyl)-1 H-pyrazol (44%). 

The bis-adducts of 4-phenyl-4/f-l,2,4-triazole-3,5-dione with 2-vinylpyridines are reported to yield, on treatment with hydrazine, pyrido[3,2-c]pyridazines unsubstituted in the pyridazine moiety together with the corresponding 4-hydrazino compounds.106... 

Bromo-l-phenylethan-l-one oxime 2 reacts with thiocyanates to give 2-thiocyana-toethan-l-one oximes 3 which, upon treatment with hydrazine hydrate or phenylhydrazine, furnish via the intermediate 4 the 2-hydrazino- or 5-phenyl-2-(phenylhydrazino)-6//-l,3,4-thia-diazines 6a, b.70 Compound 6a is also accessible from phcnacyl bromide and thiocarbohy-drazide.46 2-Bromo-1-phenylethan-1-one oxime reacts with thiourea to afford 5-phenyl-A//-1,3,4-thiadiazin-2-amine 5.70... 

Direct amination of 3(2//)-pyridazinones occurs when they are heated with hydrazine hydrate and this is a convenient route to many 4-amino-6-substituted-3(2//)-pyridazinones (Scheme 11). The reaction generally gives high yields and amination is regiospecific when the 6-position is occupied by an aromatic or heteroaromatic ring, but the parent 3(2/ -pyridazinone gives a mixture of the 4- and 5-amino-3(2//)-pyridazinones. The reaction tolerates jV-methyl substitution of the pyridazinone, but is sensitive to steric factors the presence of a 5-substituent causes a marked reduction in reaction rate, and amination does not occur with 4-phenyl-3(2//)-pyridazinone. With maleic hydrazide 4-hydrazination occurs, possibly by displacement of an intermediate amino compound or by oxidation of an intermediate 4,5-dihydro-4-hydrazino adduct both 4-hydrazino- and... 

The action of hydrazine,125,127 hydroxylamine,125,127 and guanidine306 proceeds as expected. 3-Phenyl-5-hydrazino-1,2,4-triazole (401) reacts with 402 to yield the hydrazinothiadiazole (404) this unequivocal synthesis confirms the course of the alternative formation of 404 by the cyclization of l-benzoyl-5-(3-phenyl-l,2,4-thiadiazol-5-yl)diaminoguanidine (403). Air oxidation of 404 in the presence of alkali produces the azo compound 405.307... 

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