Hydrazino

The terminal amino group of 2-hydrazino-4-phenylthiazole is also the reactive center in reactions with activated aryl halides such as 288. A solution of the product (289) obtained from this reaction when shaken with PbOj gives a deeply colored radical, whose structure has been studied by ESR (Scheme 173) (532. 533). 

Mechanistically, the reaction results from the mesomeric donor effect of the 2-hydrazino group. The coupling between the two molecules takes place in the 5-position (Scheme 48). 

Purine, 2,6-dithioxo-1,2,3,6-tetrahydro-dethiation, 5, 558 Purine, 8-ethoxy-synthesis, 5, 577, 596 Purine, 6-ethoxycarbonylmethyl-nucleoside synthesis, 5, 561 Purine, 8-ethoxy-7-methyl-synthesis, 5, 577 Purine, 9-ethyl-synthesis, 5, 593 Purine, 6-fonnyl-reactions, 5, 547 synthesis, 5, 593 Purine, 8-fonnyl-reactions, 5, 547 Purine, 2-fluoro-synthesis, 5, 597 Purine, 6-fluoro-alkylation, 5, 529 synthesis, 5, 563, 573 Purine, 6-fluoro-9-methyl-reactions, with ammonia, 5, 562 Purine, 6-furfurylamino- — see Kinetin Purine, 9-glycofuranosyl-synthesis, 5, 572 Purine, 2-glycosyl-synthesis, 5, 587 Purine, 8-glycosyl-synthesis, 5, 585 Purine, 9-glycosyl-synthesis, 5, 572 Purine, 8-halo-synthesis, 5, 598 Purine, 2-hydrazino-synthesis, 5, 593 Purine, 8-o -hydroxyethyl-synthesis, 5, 574... 

Selenazole, 2-aryl-4-chloromethyl-hydrolysis, 6, 344 Selenazole, 2-diethylamino-nitration, 6, 341 Selenazole, 2,4-dimethyl-oxidation, 6, 341 Selenazole, 2-hydrazino-oxidation, 6, 342 Selenazoles, 6, 339-347 electrophilic substitution, 6, 340 hetero fused synthesis, 6, 344 mass spectra, 6, 340 mesoionic... 

For the first time the sensitization of Tb luminescence by Cu ions has been detected in solution of Tb-Cu complex with l,5-bis(2-hydrazino-carbophenoxy)-3-oxapentane (L). 

Girard Reagent T (2-hydrazino-N,N,N-trimethyi-2-oxo-ethanaminium chioride) [123-46-6] M 167.6, m 192 . Should be crystd from absolute EtOH (slight decomposition) when it has a slight odour, and stored in tightly stoppered containers because it is hygroscopic. 

Reaction of 2,4-dichloro-l,5-naphthyridine with ammonia (170°, 20 hr), hydrazine (100°, 16 hr), or aqueous hydrochloric acid (100°, 3 hr) was shown to yield the 2-amino- (47% yield) and 2-hydroxy-4-chloro derivatives (66% yield), but 2-hydrazino substitution (68% yield) was assumed. Disubstitution with ammonia (190°, 4 hr), hydrazine (100°, 48 hr), and ammonia-phenol (180°, 6 hr) occurred in high yield. Displacement of the 4-oxo group in 2,4-dioxo-l,5-naphthyridine occurs with aniline plus its hydrochloride (180°, 12 hr, 88% yield) to yield 429. Oxo groups in the 2- or 4-positions were... 

Attempts to obtain 5-nitro-l,7-naphthyridine and 3,6-dinitro-l,8-naph-thyridine (83) from the corresponding 8-chloro-5-nitro-l,7-naphthyridine and 2-chloro-3,6-dinitro-l,8-naphthyridine using the similar reaction failed (85JHC761 98MI2). However, 3,6-dinitro-l,8-naphthyridine (83) could be prepared in 21% yield by hydrazino-dechlorination of 2-chloro-3,6-dinitro-1,8-naphthyridine (82) and subsequent cupric sulfate oxidation of the intermediate 2-hydrazino-3,6-dinitro-l,8-naphthyridine (93LA471). 

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. ... 

It has also been stated that the 5-position of selenazoles is more reactive toward electrophilic substitution than that of thiazoles. Such reactivity is still further increased by substituents in the 2-position of the selenazole ring, which can have an —E-effect. Simultaneously, however, an increasing tendency toward ring fission was observed by Haginiwa. Reactions of the selenazole ring are thus limited mainly to the 5-position which, specially in the 2-amino-and the 2-hydrazino-selenazoles, is easily substituted by electrophilic reagents. However, all attempts to synthesize selenazole derivatives by the Gattermann and by the Friedel-Crafts methods... 

As a result of various side reactions, the yields are relatively low. However, in no case was ring fission found during the oxidations. Specially noteworthy is the ease with which the two methine groups in the 5-position of the 2-hydrazino-selenazoles are coupled together. Reference to models indicates that the quinonoid dyes exist in the trans form. 

The cyclization of the 2-hydrazino-4-methylquinohne derivatives of sugars 740 by the action of ferric chloride to give the acyclic nucleosides 741 (94MI295) (Scheme 128). 

Chloro-2-hydrazino-4-phenylquinoline A stirred mixture of 2,6-dichloro-4-phenylquino-line 12.7 g,0.01 mol) and hydrazine hydrate (6.8 g) was refluxed under nitrogen for 1 hour and concentrated in vacuo. The residue was suspended in warm water, and the solid was collected by filtration,dried and recrystallized from ethyl acetate-Skelly B hexanes to give 1.81 g (67% yield) of 6[Pg.46]

Chloro-2-hydrazino-5-phen.vl-3A/-l,4-benzodiazepine 4-Oxide (40c) Typical Procedure 235... 

Hydrazino-3//-l, 4-benzodiazepines, such as 14, are transformed into triazolobenzodiazepines 15 by reaction with ortho esters241 or with acyl chlorides and subsequent heating in acetic acid (see Houben-Weyl, Vol. E8d, p502fif).242... 

Dinuclear cyanines, see Thiazoiocyanines 2,2 -Dioxo-A-3,3 -biselenazol-5.5 -inylidene-bis hydrazones, from 2-hydrazino-selenazoles, by oxidation with FeCl3 and H,Oj, 252... 

H2NNH2 H20, EtOH, reflux, 3h 92%) 2-hydrazino-3-propyl- (89, R = Pr) (>95%), 2-hydrazino-3-pentyl- (89, R = C5Hn) (79%), and 2-hydrazino-3-nonylquinoxaline (89, R = C9H19) (83%) were made simi-larly.235... 

Chloro-3-methyl-6-nitroquinoxaline (96, R = Cl) gave 2-hydrazino-3-methyl-6-nitroquinoxaline (96, R = NHNH2) (H2NNH2 H2O, EtOH, 20°C, lh >95% H2NNH2 H2O, EtOH, reflux, 3h 60% the second of these procedures appears to be a classical example of overkill in nucleophilic displacement that results in a lower yield). 

Dichloroquinoxaline 4-oxide (119, R = C1) gave 6-chloro-2-hydrazino-(119, R = NHNH2) (H2NNH2 H20, EtOH, reflux, 2h 67%), 6-chloro-2-(A -methylhydrazino)- (119, R = NMeNH2) (MeHNNH2, CHCI3, reflux, 2h ... 

Hydrazino-3-methyl-7-nitroquinoxaline (223, R = NHNH2) gave 2-methyl-6-nitroquinoxaline (223, R = H) (PbOi, HjO, PhH, reflux, 15 h 63%)." ... 

Hydrazino-3-methylquinoxaline (247) and phenacyl cyanide gave 2-(3-amino-5-phenylpyrazol-l-yl)-3-methylquinoxaline (248) (EtOH, reflux, 4 h 60% or neat reactants, fused, 5 min >50%) analogs likewise. " ... 

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