Hydrazines acetylation

Hydrazine bisthiosemi, clethodim, clofentezine, diclomazine, difenzoquat, ferimzone, flupoxam, maleic hydrazide, metamitron, methidathion, metribuzin, pymetrozine, tebuthiuron, thiazafluron, triclopyr Hydrazine (acetyl) metamitron Hydrazine (tertiobutyl) tebufenozide Hydrazine (p.tertio butyl benzyl) pyridaben Hydrazine (2.4 dichloro phenyl) sulfentrazone Hydrazine (dimethyl) daminozide Hydrazine (2.6 dimethyl phenyl) oxadixyl... 

Forty-eight hours after a 1-hour exposure to 10-500 ppm hydrazine, approximately 8.4-29.5% of the inhaled dose was excreted in the urine of rats (Llewellyn et al. 1986). Most of the recovered dose was excreted during the first 24 hours. Three metabolites were identified in the urine as unchanged hydrazine, acetyl hydrazine, and diacetyl hydrazine. No other studies were located regarding excretion in animals after inhalation exposure to hydrazine. 

Bonnet D, OUivier N, Gras-Masse H et al (2001) Chemoselective acylation of fully de nt)tected hydrazine acetyl peptides. Application to the synthesis of lipopeptides. J Org Chem 66 443-446... 

Pyridyl)hydrazine (Aldrich), 4-acetylpyridine (Acros), N,N,N -trimethylethylenediamine (Aldrich), methylrhenium trioxide (Aldrich), InQj (Aldrich), Cu(N0j)2-3H20 (Merck), Ni(N03)2-6Il20 (Merck), Yb(OTf)3(Fluka), Sc(OTf)3 (Fluka), 2-(aminomethyl)pyridine (Acros), benzylideneacetone (Aldrich), and chalcone (Aldrich) were of the highest purity available. Borane dimethyl sulfide (2M solution in THE) was obtained from Aldrich. Methyl vinyl ketone was distilled prior to use. Cyclopentadiene was prepared from its dimer immediately before use. (R)-l-acetyl-5-isopropoxy-3-pyrrolin-2-one (4.15) has been kindly provided by Prof H. Hiemstra (University of Amsterdam). 

The principal reactions of this class of compounds are summarized in Scheme 172. In most of these reactions the reactive nucleophilic center is the terminal NHj group, although the other exocyclic nitrogen may also be involved, as shown by acetylation, which yields 284 and 285. However, the structure of compound 281 is not the one proposed in a recent report (1582) that attributes the attack to the other exocyclic nitrogen. The formation of osazones (287) from sugars, 2-hydrazinothiazoles, and hydrazine has been reported (525, 531). 

Acetyl-3-mercaptopropanol reacts with acetaldehyde in the presence of hydrazine hydrate to yield 2,4-dimethyl-5-(/3-hydroxyethyl)thiazole (10), R, = Rj = Me, R3 = CH2CH2OH (556). 

Sorm et a/. prepared azacytidine and some of its derivatives in a similar way. The 4-thio derivative was obtained from 2, 3, 5 -tri-0-acetyl- or 2, 3, 5 -tri-0-benzoyl-6-azauridine by treatment with phosphorus pentasulfide this liberated 4-thio-6-azauridine (126) which was identified with 4-thio-6-azauracil on comparing the UV spectra. Treatment with ammonia produced 6-azacytidine (127) treatment with hydrazine, hydroxylamine, and n-butylamine yielded the corresponding derivatives. 

Acetyl-l 2-ketochenodeoxycholic acid Hydrazine hydrate Potassium hydroxide... 

To 1,400 ml of an approximately 50% water/triglycol solution of the potassium salt of cheno-deoxycholic acid, obtained by the Wolff-Kishner reduction (using hydrazine hydrate and potassium hydroxide) from 50 g of 7-acetyl-12-ketochenodeoxycholic acid, 220 ml of dilute hydrochloric acid is added to bring the pH to 2. The solution is stirred and the crude cheno-deoxycholic acid precipitates. The precipitate is recovered and dried to constant weight at about 60°C. About 36 g of the crude chenodeoxycholic acid, melting in the range of 126°-129°C, is obtained. 

Another dihydro derivative has been described in connection with medicinal chemical studies. Thus, reaction of 2-(chloromethyl)quinazoline-3-oxide (3) with hydrazine gives hydr-oxytriazocinamine 4 (and not a diazepine derivative as originally assigned), vigorous acetylation of which results in a rearrangement to give oxazolotriazocine 5.10... 

The reaction of l-acetyl-3-indolinone 124 with carbon disulfide in the presence of sodium hydride gave thiazolo[3,4-with hydrazine or phenylhydrazine gave 2H[ 1,2,4]triazino[4,5-a]in-dole 126 (75YZ980) (Scheme 29). 

Reaction of hydrazine 165 with a number of monosaccharides give hydrazones 166 (92BCJ546). Their acetylations gave peracetyl derivatives 167. The same reactions were extended to the /V-methyl and the 7-methyl derivatives of 165 (93 JPROO). That compounds 166 exist as open-chain structures was based on a 2D NMR study (93MI1) (Scheme 35). 

Amino-5-hydrazinopyrazole dihydrochloride 300 is a good source for the synthesis of this type of heterocyclic compound [78JCS(P1)885] and it was prepared by reaction of malononitrile with two equivalents of hydrazine. Reaction of 300 with ethyl pyruvate afforded 301. Unstable hydra-zone 302 formed when 300 was boiled with diacetyl rapidly cyclized to 303. Reaction of 300 with benzil gave 304 directly, which gave an acetyl derivative and resisted reductive deamination. On the other hand, a polymer was isolated from the reaction of 300 with glyoxal (Scheme 65). 

Treatment of 2-acetyl- or 2-formyl-benzimidazole 587 with hydrazines gave the corresponding hydrazones 588, which cyclized with ethyl chloro-formate to give [84JCR(S)384] triazinobenzimidazoles 589. 

JV-Acetyltransferases (NATs) catalyze the conjugation of an acetyl group from acetyl-CoA on to an amine, hydrazine or hydroxylamine moiety of an aromatic compound. NATs are involved in a variety of phase II-diug metabolizing processes. There are two isozymes NAT I and NAT II, which possess different substrate specificity profiles. The genes encoding NAT I and NAT II are both multi-allelic. Especially for NAT II, genetic polymoiphisms have been shown to result in different phenotypes (e.g., fast and slow acetylators). 

In Dimethoxymethan wird z. B. 2-[l-Dimethylamino-propyl-(2)]-l-acetyl-hydrazin zu 2-Athyl-l-[/-dimethylamino-propyl-(2)]-hydrazin (17% d.Th.) reduziert1 2 und 2-Phenyl- 1-acetyl-hydrazin zu 2-Athyl-l-phenyl-hydrazin (89% d.Th.)3 ... 

Condensation of phenylalaninenitrile, prepared from phenyl acetaldehyde, with 1-oxime of pyruvaldehyde afforded the pyrazine N-oxide, which was further rearranged to give the N-acetyl pyrazinone. The acetyl groups were removed by treatment with hydrazine to give the target 6-aminopyrazinone. 

As mentioned before for other azolide reactions, acylations can be carried out with polymer-supported azolides as acylating reagents. For example, acetic acid hydrazide can be prepared with a polymer of l-acetyl-4-vinyl-imidazole/divinylbenzene (96 4) and hydrazine (no diacylation occurs when this method is used) [122]... 

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