Benzonitrile Benzoquinone

Dihydro-l,2-benzisoxazole was prepared by the cycloaddition of benzonitrile N-oxide to 1,4-benzoquinones with subsequent oxidation of the hydroquinone (Scheme 174) (72JAP(K)7242659, 50G140). 

The addition of the anion of a-bromo-a-nitrotoluerie (564) to cyclohexene gave the hexahydro derivative (565) of 3-phenyl-l,2-benzisoxazole (75TL2131). An unusual hexahydro derivative (566) was produced by the bis addition of benzonitrile N-oxide to benzoquinone (67AHC(8)277). 

For example, reductive elimination of benzonitrile from (Et3P)2Pd(CN)Ph is promoted by the addition of triethyl phosphite [4], addition of benzoquinone promotes reductive eliminations in palladium chemistry (Chapter 12), etc., but in all cases different roles can be envisaged, such as simple ligand exchange. 

An alternative approach to form a cyclobutylmethyl cation from a vinylcyclobutane uses organopalladium chemistry.25 For example, exposure of l-methyl-7-vinylbicyclo[4.2.0]octan-7-ol to 5mol% of bis(benzonitrile)palladium dichloride and 1,4-benzoquinone in boiling tetrahydrofuran gave the desired 6,9-dimcthylbicyclo[4.3.0]non-l(9)-en-8-one (7) in 67% yield.25 The mechanistic pathway of this transformation is shown. Further examples, showing the utility of the reaction, are shown for the rearrangement to 8.23... 

Reactions of /)-benzoquinone and its derivatives with alkoxide ions (RO R = H, Me, Et, i-Pr, PhCH2) in MeCN also result in formation of the corresponding semiquinone radical anions accompanied by the formation of RO-substituted p-benzoquinones, which are the oxidized products of p-benzoquinones [360], Detailed product and kinetic analyses of the reactions indicate that RO-adduct anion of /)-benzoquinone is an actual electron donor and that RO is acting as a very strong base or nucleophile rather than a one-electron reductant in an aprotic solvent, such as MeCN [360], Similarly, the reaction of C o with methoxide anion (MeO ) in benzonitrile (PhCN) results in the disproportionation of Cgo to yield both C(,o and the methoxy adduct [360]. Spectroscopic and kinetic studies also indicate that a methoxy adduct anion of Ceo is a real electron donor and that MeO is acting as a very strong base or nucleophile rather than an electron donor in PhCN [360],... 

Figure 3.3 The Ea of benzonitrile, 1,2 dicyanoethylene, 1,2 dicyanobenzene, maleic anhydride, benzoquinone, s-tetracyanobenzene, fluoranil, chloranil, hexacyanobenzene, tetracyanoquinodimethane, tetracyanoethylene, and hexacyanobutadiene reported in 1975 [64] from reduction potentials and charge transfer absorption maximum versus the current best values. These are precision and accuracy plots. The slopes are determined with a fixed intercept of zero, so that the displacements are random uncertainties.

Benzonitrile, 2,6-dimethoxy-, 22, 35 Benzophenone, 23, 99 Benzophenone azine, 24, 55 Benzophenone hydrazone, 24, 54 1,2-Benzopyran-3-carboxylic acid, 2-oxo-, ethyl ester, 28, 24 Benzopyrrole, 23, 42 Benzo(j) )quinolizine, 1,2,3,5,6,7-HEXAHYDRO-, 26, 40 -Benzoquinone, 26, 25 Benzothiazole, I-amino-5-methyl-, 22,16... 

Polymethyl 3a,4,7,7a-tetrahydroindoxazenes (77) are obtained by thermal rearrangement of the benzonitrile oxide-hexamethyl-Dewar-benzene cycloadducts (76).90 Reaction of 2,4,6-trimethylbenzonitrile oxide with 3,6-dimethyl-p-benzoquinone yields the 4,7-dioxo-3a,4,7,7a-tetrahydroin-doxazene78(Ar = 2,4,6-Me3C6H2) or its regioisomer, and addition proceeds similarly with 2,6-dimethyl-p-benzoquinone. In a number of other examples, nitrile oxides were found to cycloadd to the C=0 bond of quinones.91... 

BZ was al so partially oxidized by Ag(II) in a small H-cell with stationary platinum electrodes. Compounds identified in anolyte extracts included phenol, hydroquinone, benzoquinone, benzaldehyde, benzoic acid, methyl benzoate, benzonitrile, benzonitrile aldehyde, and 4-nitro butylnitrile. The yellow color of the anolyte was probably due to benzoquinone, which had a relatively high concentration. A compound which was tentatively identified as benzoquinone epoxide ( 11403) was present at the highest concentration and is believed to be a product of the oxidation of benzoquinone. Numerous nitrated aromatics were also detected and include nitrobenzene, dinitrobenzene isomers, nitrophenol isomers, and dinitnophenol isomers. Intermediates are summarized in Table 3 and classified as I. BZ substrate II. nitrated BZs HI. phenols, quinones, and epoxides IV. nitrated phenols V. BZ substituted with aliphatic and aromatic... 

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