Hydrazides, oxidation

The substituents may be essential for the chemical reaction of the hydrazide oxidation itself the excitation step may depend on them or they may affect the fluorescence efficiency of the product. It would appear that all three influences are at work both quantitatively and qualitatively. For example, substitution may result in general instability towards oxidation as in the cases of 3,6-diamino- or 3-amino-6-methoxy phthalhydrazide [8]. The ease of oxidation on the chemiluminescent pathway is certainly significant, although it is difficult to separate this from the influence on the population of the excited state. An example of this effect is that of the 4-dialkylamino-phthalhydrazides. Differences in chemiluminescence quantum yields of up to 600-fold were observed, whereas the fluorescence quantum yields of the corresponding 4-dialkyl-amino phthalates only differ by a factor of about 10 [9]. 

Thiazole carboxylic acid hydrazides were prepared in a similar way (444, 445). Thus by refluxing thioacetamide or thiobenzamide with y-bromoaceto acetic ester arylhydrazones (83) for several hours in alcohol the 4-carboxythiazole derivatives (84) listed in Table II-ll were obtained (Scheme 36) (656). This reaction is presumed to proceed via dehydration of the intermediate, thiazoline-S-oxide. 

Pyridazine-3,6-diones (diazaquinones) are prepared from cyclic hydrazides by oxidation with lead tetraacetate or other oxidizing agents, such as r-butyl hypochlorite, chlorine or nickel peroxide. 

A number of di- and trisubstituted hydrazides of penicillin and cephalosporin derivatives were prepared to study the effect of A-substitution on ease of oxidative cleavage. ... 

Aminosalicylic acid (5-amino-2-hydroxybenzoic acid) [89-57-6] M 153.1, m 276-280 , 283 (dec), pK 2.74 (CO2H), pK 5.84 (NH2). Cryst as needles from H2O containing a little NaHS03 to avoid aerial oxidation to the quinone-imine. The Me ester gives needles from C6H6, m 96°, and the hydrazide has m 180-182° (From H2O). [Fallab et al. Helv Chim Acta 34 26 1951, Shavel J Amer Pharm Assoc 42 402 1953.]... 

Deuterio-3-iiitro-l,6-iiaphthyridiiie (168) was prepared from 4-chloro-3-iiitro-l,6-iiaphthyridiiie (166) by a reaction with tosyl hydrazide and subsequent hydrolysis of the 4-tosylhydrazino derivative (167) with Na2C03/ D2O solution (83RTC359). 7-Deuterio-l,8-naphthyridin-2(lH)-one was prepared by heating l,8-naphthyridin-2(lH)-one with deuterium oxide at 230°C for 35 h (85JHC761). Tliis deuterio compound could be converted into 2-chloro-(or 2-ethoxy-) 7-deuterio-3,6-dinitro-l,8-naphthyridine. 

In the other extreme, ethyl 3-oxohexanoate 75 required fusion with 3-pyridyl-hydrazide 73a or 3-hydrazinocarbonyl-pyridine-l-oxide 73b at 120°C in order to give the corresponding pyrazol-3-ones 76a,b (92AF1350) (Scheme 22). Depending on the reaction conditions, the reaction of ethyl 3-oxo-3-phenylpropanoate 77 and cyanomethylhydrazide 78 gave different products. Thus, fusion at 140°C gave pyrazol-3-one 79 and N,A -bis(cyanoacetyl)hydrazine 80, while heating in ethanol... 

Anilinofervenulin 4-oxides 151 were synthesized by the reaction of 6-hydra-zino-l,3-dimethyluracil with triethyl orthoformate, followed by the treatment of the hydrazide 152 with aniline and further cylization of 153 in the presence of potassium nitrate in acetic acid (82JHC1309). 

A piridazine ring forms the nucleus for a rather unusual nontricyclic antidepre.ssant. Condensation of the keto ester 136 with hydrazine leads to the cyclic hydrazide 137. Oxidation, for example with bromine, gives the corresponding pyridazone 138. The oxygen is then replaced by chlorine by reaction with phosphorus oxychloride. Displacement of the halogen in 139 with N-ethylami-nomorpholine affords minaprine 140 [30]. 

The available studies indicate that diimide has been used as a reducing agent for the preparation of HNBR. It has been used mainly as an alternative for hydrogenation of nitrile rubber latex. The use of diimide to hydrogenate low-molecular weight olefines is well known in the organic literature [93]. Diimide can be conveniently generated in situ by thermal treatment of solutions of p-tolu-enesulfonyl hydrazide or oxidation of hydrazine. 

Dehydrogenation of the hydrazide derivative 33 with mercuric oxide in the presence of ethylene diamine tetraacetic acid (EDTA) gave 34 and 35 (77AP588). The latter (35) was prepared from a reaction of ester 36 with the appropriate lactam 37 (Scheme 11). 

Furo[3,4-c][l,2,4]triazines 201 were prepared (75USP3962240 77USP-4013767) by condensing furandione 199 with the respective 2-aryl or pyri-dylcarboximidic acid hydrazide 200. Compound 201 (X = N) was oxidized to its N-oxide. Both 200 and 201 have sedative and tranquilizer properties (Scheme 42). 

Van Zyl JM, BJ van der Walt (1994) Apparent hydroxyl radical generation without transition metal catalysts and tyrosine nitration during oxidation of the anti-tubercular drug, isonicotinic acid hydrazide. Biochem Pharmacol 48 2033-2042. 

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