S. S. Mochalov

Mercuration of some styrenes and phenylcyclopropanes. The effect of the aromatic nitro group on reductive demercuration with sodium borohydride

Abstract Mercuric acetate reacts with o - and p -nitrostyrenes and with nitrophenylcyclopropanes in methanol or glacial acetic acid to give β- and γ-mercurated nitroderivatives, respectively. In contrast to the nitrostyrenes, mercuration of the corresponding nitrophenylcyclopropanes only occurs in the presence of perchloric acid as catalyst. 2,4-Dinitrophenylcyclopropane does not react with mercuric acetate even under the catalysis conditions. Aromatic nitro groups decelerate reductive demercuration of γ-mercurated alcohols and their derivatives with sodium borohydride to the extent that other fragments of the molecule may undergo reduction while the HgX function remains intact. This result may be explained by intermolecular coordination of the nitro group to the mercury atom, which reduces effective positive charge on the metal and hinders the attack by the reducing reagent.

Nitration of 5-formyl-substituted 2-cyclopropylfurans and 2-methylfurans and the corresponding thiophenes

In the nitration of 5-formyl-substituted 2-cyclopropylfurans and the corresponding thiophenes, in addition to the formation of the corresponding 3-nitro derivative the replacement of the formyl group by a nitro group takes place. For a thiophene derivative the latter direction of the reaction is observed to a substantially smaller degree. Under nitration conditions, 5-formylsylvane is converted only into 5-nitrosylvane, while the corresponding formylmethylthiophene is nitrated exclusively in position 3. The difference observed in the behavior on nitration of the furans and thiophenes studied is explained by the different degrees of participation of the heteroatom in the delocalization of the charges in the heterocyclic ipso-ions formed as intermediates.

Synthesis and biological activities of substituted 2- and 3-chloropropylthiophenes

Beginning in 1970 we have systematically studied the potential reactivities and biological properties of several thiophene derivatives. In these studies special attention was paid to development of synthetic methods for various functionally substituted cyclopropylthiophenes. It was proposed that the strength of the electronic bonds in the triangular ring would confer special biological properties on its derivatives. Particular attention was paid to obtaining cyclopropylthiophenes substituted with electron-accepting groups in the heterocyclic ring, which according to the literature [2] increases the antibacterial activity of several medicinal compounds in comparison with unsubstituted analogs or analogs substituted with electron-donating groups.

Behavior of 2-nitroso-4-nitropropiophenone under conditions of cyclization to haloanthranils

The cyclization of 2-nitroso-4-nitropropiophenone under the influence of hydrogen chloride proceeds in a more complex manner than in the cases previously described for other 4-substituted-2-nitrosopropiophenones: three, rather than two, haloanthranils are formed, and their formation is accompanied simultaneously by a number of redox transformations. This fact is explained by a decrease in the ability of the carbonyl group in the investigated ketone to undergo protonation.

Cyclization of o-nitrosoacylbenzenes to anthranils

Abstract5-Bromo- and 5-methoxy-3-ethylanthranils, respectively, were obtained by cyclization of o-nitrosopropiophenone under the influence of hydrogen bromide in benzene and hydrogen chloride in methanol. In these reactions, the starting nitroso ketone undergoes redox transformations that also proceed readily in an inert solvent in the absence of any cyclizing reagents.

The 3,4-dihydro-N-oxo-3-ethyl-2,1-benzoxazinium cation in the synthesis of β- and γ-substituted arylbutanes and 1-aryl-2-butenes

The reaction of 3,4-dihydro-N-oxo-3-ethyl-2,1-benzoxazinium salts with reagents with nucleophilic and basic character can be used to obtain β- or γ-substituted arylbutanes and trans-1-aryl-2-butenes. The reactions proceed regiospeciflcally and are regulated by the nature of the reagents used.

New rearrangement in the 3-indolinone series

In an aqueous alcohol solution of hydrogen chloride 1-(2-propionylphenyl)amino-2-alkoxy-2-methyl-3-indolinone undergoes rearrangement to 2-(2-acetylcarbonyl)phenyl-3-ethylindazole. The structure of the rearrangement product was investigated by x-ray diffraction analysis.

Intramolecular cyclization of 2,2′-dipropionylazoxybenzenes. X-ray structural investigation of 1-(2-propionylphenylamino)-2-methyl-2-methoxyindolin-3-one

X-ray structural analysis has revealed that the product of base-promoted intramolecular rearrangement of 2,2′-dipropionylazoxybenzenes has a 1-(2-propionylphenylamino)-2-methyl-2-methoxyindolin-3-one structure, not that of 3-[1-alkoxy-1-(2-propionylphenylamino]ethylbenzo[c]isoxazole, as was previously thought.

Conversion of 2,1-benzisoxazolinium ions to anthranils by treatment with hydrohalic acids

Abstract2,1-Benzisoxazolinium ions, obtained from o-nitrophenylcyclopropanes, react with hydrobromic and hydrochloric acids to give halo-substituted benzo[c]isoxazoles.

New transformations of o-substituted azoxybenzenes

Under the influence of equimolar amounts of bases, o-propionylazoxybenzenes undergo previously unknown transformations to difficult-to-obtain cinnolinones, bisindoxyls, and indolinones. The ratios of the resulting transformation products depend on the substituent in the para position with respect to the propionyl group. Possible pathways for the transformations of monopropionylazoxybenzenes are discussed.