Oximes quinone dioximes

The nitrosation of oximes can also serve to produce N-hydroxy-N-nitrosamines (Scheme 3.9). The acidified nitrite procedure can be applied to oximes derived from terpenes [132] and hydroxyguanidine [133] for the synthesis of N-hydroxy-N-nitrosamines. However, some a, 5-uri saturated oximes were converted into pyrazole-1,2-dioxides [134]. The alkyl nitrites under basic conditions have produced interesting results. Quinone dioximes yielded only monodiazeniumdiolates [135], while simple aliphatic oximes gave products resulting from addition to the imine double bond... 

The utility of the method depends on the availability of the dioxime precursors. When the parent quinone is readily accessible, direct oximation provides a straightforward approach which has been used for the acenaphtho- and phenanthro-furazans, (22) and (94 n= 0), although in the former case mild conditions (SOCl2, 20 °C) are required for the subsequent cyclodehydration in order to avoid fragmentation of the product (73JOC1054) (see Section 4.22.3.1.1). o-Quinone dioximes can be generated by reduction of benzo-furoxans, but in many such cases direct deoxygenation to the benzofurazan is also possible. 

SYNS ACTOR Q l,4-BEi ZOQL L ONEDIOXINE 2,5-CYCLOHEX. DIENE-l,4-DIONE DIOXIME DIBENZO PQD DIOXIME-1,4-CYCLOHEXA-DIENEDIONE DIOXIME-2,5-CYCLOHEX. DIENE-l,4-DIONE G-M-F NCI-C03850 PQD QDO QUINONE DIOXIME p-QUINONE DIOXIME p-QUINONE OXIME... 

Reduction of unsaturated oximes without effect on the C=C double bond is best carried out by sodium amalgam at not too high a temperature. Quinone dioximes are best converted into the amines by use of sodium sulfide in boiling alcohol.115 Amino carboxylic acids are prepared from the corresponding oxo carboxylic acid oximes, catalytic reduction being in these cases the method of choice. 

Di-(N-nitrosohydroxylamines) from quinone dioximes 1-Oximino-l-N-nitrosohydroxylamines from oximes... 

The properties of quinones are to a certain extent similar to those of carbonyl compoimds. They form oximes, thiosemicarbazones, and phenylhydrazones. The rate of the reaction of quinones with hydroxylamine varies, and a number of quinones do not react with it at all. Substituents already present in the quinone molecule play a predominant role (16). In acid media hydroxylamine can have an oxidative influence, parallel to oximation, for example in the case of quinol, which is converted to quinone dioxime (17) free hydroxylamine can, however, have a reductive influence it reduces quinone to hydroquinone (18). 

B) Oximes. Dissolve i g. of the quinone in 5 ml. of glacial acetic acid. Dissolve i g. of hydroxylamine hydrochloride in 10 ml. of 10% aqueous sodium acetate solution and shake the mixture for 5 minutes. Cool, filter off the dioxime and recrystallise from ethanol. (M.ps., p. 549.)... 

In the next part of the section, [Ru (bpy)2L2] complexes containing oximes, dioximes and quinones are considered. We then move to [Ru(bpy)2L]"" complexes with other 0,0- and N,0-donors as well as N,S- and F,0-donor ligands. 

These compounds are obtained by action of nitrous acid on phenols, and were formerly regarded as nitrosophenols but this assumption has gradually been abandoned. They may also be obtained by action of hydroxylamine on quinones, and yield dioximes on further treatment with this reagent. It is therefore more probable that the nitrosophenols are really oximes of quinones, i. e.j quinones in which one oxygen atom is replaced by the divalent group = IN —OH. 

Quinone reacts with hydroxylamine to form a monoxime and a dioxime. This fact indicates that it contains two carbonyl groups which possess the properties of the carbonyl group in the ketones. The formulas assigned to the oximes are as follows —... 

CAS 105-11-3 EINECS/ELINCS 203-271-5 Synonyms p-Benzoquinone dioxime 1,4-Benzoquinone dioxine 2,5-Cyclohexadiene-1,4-dione dioxime Dioxime-p-benzoquinone Dioxime-1,4-cyclohexadienedione Dioxime-2,5-cyclohexadiene-1,4-dione PQD Quinone dioxide p-Quinone oxime Empirical C6H6N2O2 Formula HONC6H4NOH Properties Yel. needles si. sol. in water m.w. 138.06 m.p. 243 C (dec.)... 

The dioximes (and also monoximes) of benzoquinone, naphtha-quinone, and anthraquinone were iuvestigated by Elofson and Atkinson [97], who observed one wave in acidic and alkaline solutions and two waves in neutral solution the smallest wave, of kinetic character, was explained by nitrone — oxime isomerization at the electrode ... 

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