Oximes and derivatives

Brom-4-nitroso-methylanilin in Ger], H3C.N C6H3(Br) N.OH or H3C.HN.CgH3(Br).NO. See 4-Nitroso-3-bromonethylaniline under Bromomethylaniline and Derivatives or 3-Bromo -l,4-benzoquinone-l-methylimine-4-oxime under Benzoquinone Oxime and Derivatives... 

This section contains the chemical shifts of the oximes and derivatives which contain the -CH=N- group. The carbon-13 spectra usually display resonance bands for both the syn- and anti- forms. The oxime -CH=N- resonance is found in the chemical shift range from 137 to 158 ppm depending upon its... 

M.ps. of oximes and semicarbazones are those of the di-derivatives, except those marked which are mono-derivatives. 

Section IV, 135,5), but are unaflFected by the dimedone reagent (Section 111,70, 2). The general reactions are similar to those already given under Aliphatic Ketones (Section 111,74). Owing to their higher molecular weight, such derivatives as oximes and phenylhydrazones are frequently quite satisfactory. 

The imides, primaiy and secondary nitro compounds, oximes and sulphon amides of Solubility Group III are weakly acidic nitrogen compounds they cannot be titrated satisfactorily with a standard alkaU nor do they exhibit the reactions characteristic of phenols. The neutral nitrogen compounds of Solubility Group VII include tertiary nitro compounds amides (simple and substituted) derivatives of aldehydes and ketones (hydrazones, semlcarb-azones, ete.) nitriles nitroso, azo, hydrazo and other Intermediate reduction products of aromatic nitro compounds. All the above nitrogen compounds, and also the sulphonamides of Solubility Group VII, respond, with few exceptions, to the same classification reactions (reduction and hydrolysis) and hence will be considered together. 

An example of the electrophilic reactivity of the C-4 atom is the easy formation of oxime and phenylhydrazone derivatives (422). It has been reported, however, that 2 pheny -A-2-thiazoline-4-one does not react with phenylhydrazine (397). 

The controversy seemed then to be closed. In 1890 Hantzsch had already started his work on the structure of oximes, and his synthetic work on heterocycles was practically ended. However, 27 years later, in July 1919, Tcherniac published a new paper entitled TTiiocyanoacetone and its derivatives as isomerides (33), where, after the description of improved and generalized methods for the preparation of thiocyanoacetone he came to the explosive conclusion that the substance which has been known since 1887 as hydroxymethylthiazole is not a thiazole at all. It might be called 2-imino-4-methylthioxole, but for the sake of simplicity, and in view of the now proved existence of two other isomerides of thiocyanoacetone, it seems preferable to adopt the generic... 

Hydroxybenzaldehyde has extensive use as an intermediate in the synthesis of a variety of agricultural chemicals. Halogenation of Nhydroxybenzaldehyde, followed by conversion to the oxime, and subsequent dehydration results in the formation of 3,5-dihalo-4-hydroxybenzonitrile (2). Both the dibromo- and dhodo-compounds are commercially important contact herbicides, hromoxynil [1689-84-5] (2) where X = Br, and ioxynil [1689-83-4]( where X = I respectively (74). Several hydrazone derivatives have also been shown to be active herbicides (70). 

Hydroxyalkyl groups attached to pyridopyridazines have been converted to haloalkyl groups by standard methods and the products reacted with amines. Ketones have been converted to hydrazones and oximes and the resulting derivatives deprotected during syntheses. 

The carbonyl group forms a number of other very stable derivatives. They are less used as protective groups because of the greater difficulty involved in their removal. Such derivatives include cyanohydrins, hydrazones, imines, oximes, and semicarbazones. Enol ethers are used to protect one carbonyl group in a 1,2- or 1,3-dicarbonyl compound. 

Dihydromorphinone, Cj,Hjg03N, and derivatives. Dihydromorphinone (LIII MeO HO) is formed when morphine in solution is treated with relatively large quantities of platinum or palladium catalyst under various conditions.It melts at 262-3° and yields an oxime, m.p. > 234°. The hydrochloride is the drug known as dilaudid. On 0-methyla-tion dihydromorphinone yields dihydrocodeinone (see above), and when dissolved in ether and treated with methyllithium the corresponding tertiary alcohol, 6-methyldihydromorphine, CigHggOgN, m.p. 209-211°, Wd ° 14i7° (EtOH), is formed. This on methylation with diazomethane gives 6-methyldihydrocodeine as described above (Small and Rapoport... 

On distillation with zinc dust the alkaloid gives an easily hydrogenated pyrrole base, and on dehydrogenation by platinised asbestos at 260-290 it yields (1) an amorphous dehydro-base, which forms an oxime and a methiodide, C17H23O4N. Mel, decomp. 227-8 , and contains a lactone and a methoxyl group, (2) a neutral pyrrole derivative, and (3) an acid giving a dark green colour with ferric chloride (1939). 

Imine formation from such reagents as hydroxylamine and 2,4-dinitro-phenylhydrazine is sometimes useful because the products of these reactions— oximes and 2,4-dinitrophenylhydrazones (2,4-DNPs), respectively—are often crystalline and easy to handle. Such crystalline derivatives are occasionally prepared as a means of purifying and characterizing liquid ketones or aldehydes. 

The problem of slow turnover has been noted. Initial reaction of a nucleophilic group, e.g. imidazole or oximate, in a functional micelle, with a carboxylic or phosphoric ester, for example, gives an acylated or phosphory-lated imidazole or oxime, and these derivatives hydrolyze slowly to regenerate the nucleophile. Kunitake and Shinkai (1980) discuss a number of reactions in micelles which contain both nucleophilic and basic groups which are potentially capable of acting as bifunctional reagents (Tonellato, 1979, Kunitake and Shinkai, 1980 Bunton, 1984)... 

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