G. V. Palamarchuk

Thiocyanation of N-arylsulfonyl-, N-aroyl-, and N-[(N-arylsulfonyl)benzimidoyl]-1,4-benzoquinone imines

Reactions of thiocyanate ion with N-aroyl-, N-arylsulfonyl-, and N-(N-arylsulfonylbenzimidoyl)-1,4-benzoquinone imines follow the 1,4-addition pattern, and the adducts undergo intramolecular cyclization to give the corresponding N-substituted 5-amino-1,3-benzoxathiol-2-ones as final products.

Synthesis and structure of N-alkyl(aryl)aminocarbonyl-1,4-benzoquinone imines

New N-alkyl(aryl)aminocarbonyl-1,4-benzoquinone imines were synthesized by reaction of isocyanates with the corresponding substituted 4-aminophenols, and their structure was determined on the basis of 1H and 13C NMR spectra and X-ray diffraction data.

Synthesis and structure of N-aryl(phenoxy, benzylidene)acetyl-1,4-benzoquinone monoimines

New N-aryl(phenoxy, benzylidene)acetyl-1,4-benzoquinone monoimines were synthesized by reaction of aminophenols with arylacetyl, phenoxyacetyl, and cinnamoyl chlorides in dimethylformamide-acetic acid (1: 3) in the presence of anhydrous sodium acetate. Structural parameters of the products and their probable biological activity were determined.

Reaction of N-alkyl(aryl)aminocarbonyl-1,4-benzoquinone monoimines with alcohols

Reactions of N-alkyl(aryl)aminocarbonyl-3,5-dimethyl-1,4-benzoquinone monoimines with alcohols led to the formation of products of 1,2-addition, quinolide compounds. They are the final products in reactions with alkyl derivatives, but in event of aryl derivatives they underwent cyclization with the subsequent elimination of the alcohol molecule to provide 4,7a-dimethyl-1-aryl-7,7a-dihydro-1H-benzimidazole-2,6-diones.

Thiocyanation of N-aryl, N-acetyl, and N-[arylsulfonylimino(methyl)methyl] derivatives of 1,4-benzoquinone monoimine

N-[arylsulfonylimino(methyl)methyl] derivatives of 1,4-benzoquinone monoimine with alkyl substituents in the quinoid ring have been synthesized and their spectral characteristics were determined. The thiocyanation of N-aryl, N-acetyl, and N-[arylsulfonylimino(methyl)methyl] derivatives of 1,4-benzoquinone monoimine depending on the LUMO energy of the initial quinone monoamine affords derivatives of benzo[d][1,3]oxathiol-2-ones and benzo[d]oxazole-2(3H)-thiones.

Activated sterically strained C=N bond in N -substituted p -quinone mono- and diimines: XIII. Reactions of N -alkyl(aryl, trifluoromethyl)sulfonyl-, N -arylsulfinyl- and N -arylsulfanyl-1,4-benzoquinone monoimines with alcohols

Steric strains arising between the substituent atoms at nitrogen (S, SO, or SO2) and the methyl group located in positions 3 or 5 of the quinoid ring of 3,5-dimethyl-substituted quinone monoimines lead to the increased angle C=N-S. As a result in these quinone monoimines the reactions of 1,2-addition become thermodynamically possible since the formation of quinolide structures with the sp3-hybridized carbon atom removes the steric strain.

Halogenation of n-substituted p-quinone monoimines and p-quinone monooxime esters: VIII. Halogenation of N-aroyl(arylsulfonyl)-2,6-di-tert-butyl-1,4-benzoquinone monoimines and their reduced forms

Chlorination of N-aroyl(arylsulfonyl)-2,6-di-tert-butyl-1,4-benzoquinone imines gave Z and E isomers of 4-arylsulfonylimino-2,6-di-tert-butyl-5,6-dichlorocyclohex-2-en-1-ones and Z isomers of 4-aroyl-(arylsulfonyl)imino-2,6-di-tert-butyl-5,5,6-trichlorocyclohex-2-en-1-ones, in which the tert-butyl group on the sp3-hybridized carbon atom occupies exclusively the axial position. The formation of Z/E-isomeric structures is related to configurational stability of the chlorination products. The chlorination of 4-aroylamino-2,6-di-tertbutylphenols was found to be accompanied by replacement of one tert-butyl group by chlorine atom with formation of 4-aroylimino-6-tert-butyl-2,3,5,6-tetrachlorocyclohex-2-en-1-ones.

Reaction of N-aryl-1,4-benzoquinone imines with sodium arenesulfinates

N-Aryl-1,4-benzoquinone imines reacted with sodium arenesulfinates to give products of orbital-controlled nucleophilic 1,4- and 6,3-addition.

Activated sterically strained C=N bond in N-substituted p-quinone mono- and diimines: XIV. Reaction of some 3,5-dimethyl-1,4-benzoquinone monoimines with alcohols

Steric strain in the C=N-C fragment in 3,5-disubstituted N-acyl-1,4-benzoquinone monoimines, unlike their N-arylsulfonyl analogs, leads to increase of the C=N-C angle above 130° or twisting of the double C=N bond and loss of planarity of the quinoid ring. This structural transformation enhances the reactivity of the C=N bond so that 1,2-addition of alcohols becomes possible with formation of sterically unstrained cyclohexadienone structure with sp3-hybridized C4 carbon atom.

Halogenation of N -substituted p -quinone monoimines and p -quinone monooxime ethers: XIV. Halogenation of N -[arylsulfonylimino(phenyl)methyl]-2,5-dialkyl-1,4-benzoquinone monoimines and their reduction products

Despite steric hindrances created by the bulky substituent on the nitrogen atom, halogenation of 2,5-dialkyl-N-[arylsulfonylimino(phenyl)methyl]-1,4-benzoquinone monoimines fairly readily gives their derivatives having two halogen atoms in the quinoid ring.