Preparation of certain 2-N-alkylamino-and 2-N,N-dialkylamino-10-methylphenothiazines via phenothiazyne

The treatment of 2-chloro-10-methylphenothiazine, 1 , with lithium alkylamide/alkylamine or lithium dialkylamide/dialkylamine yields the corresponding 2-N-alkylamino-or 2-N,N-dialkylaminophenothiazines in good yields via phenothiazyne. No significant reduction of 1 to 10-methylphenothiazine is observed. Yields of amines obtained by this method are considerably higher than those obtained by reacting 1 with sodamide in refluxing amine solvent. Attempts to introduce the -CH₂CN moiety onto the phenothiazine nucleus by treating 1 with sodamide and acetonitrile in liquid ammonia produced only 2-amino-10-methylphenothiazine.     

Photolysis of 2-dialkylamino-3-methyl-1,4-naphthoquinones

The photolysis of 2-dialkylamino-1,4-naphthoquinones is significantly more efficient when a methyl group is at C³. The quantum yields are 2–6 times greater than for 2-dialkylaminonaphthoquinones lacking a methyl group. 2-Monoalkyl-amino-1,4-naphthoquinones also undergo photochemical dealkylation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2387–2392, October, 1991.     

Thermal conversions of 2-azido-3-piperazino-substituted 1,4-naphthoquinones

Conclusions The 2-azido derivatives which are formed when 2-chloro-3-(4-acylpiperazino)-1,4-naphthoquinones are reacted with NaN₃ in DMF are converted during the reaction to the corresponding 2-amino derivatives and the cyclization products-naphthimidazolediones.2. It is shown that the precursors of the naphthimidazolediones are 1-(3-amino-1,4-naphthoquinonyl-2)-1,4,5,6-tetrahydropyrazines, which are products from dehydrogenation of the piperazine ring.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2822–2826, December, 1988.     

Thermal decomposition of 2-amino-3-aziridino-1,4-naphthoquinones

The course of the thermal decomposition of various 2-amino-3-substituted aziridino-1,4-naphthoquinones (Ia-g) was investigated. In all the cases, the thermal decomposition gave variable amounts of 2,3-diamino-1,4-naphthoquinone (II) and of substituted 1,2,3,4,5,10-hexahydrobenzo[g]quinoxaline-5,10-diones (IIIa-g) with complete stereospecificity. The decomposition of the aziridines Ib,f also gave significative amounts of 2-amino-3-allylamino-1,4-naphthoquinones (IVb,f). In the case of 2-amino-3-(2′-phenyl-3′-ethylaziridino)-1,4-naphthoquinone (Ig), the formation of trans-1-phenyl-1-butene (V), 2-(1-phenylpropyl)-1H-naphtho-imidazole-4,9-dione (VI), 2-phenyl-3-ethyl-3,4,5,10-tetrahydrobenzo[g]quinoxaline-5,10-dione (VII), 2-phenyl-3-ethyl-5,10-dihydrobenzo[g]quinoxaline-5,10-dione (VIII), and a mixture of cis- and trans-4H-2,3,5,6-tetra-hydro-2-phenyl-3-ethyl-5-iminonaphtho[1,2-b]oxazin-6-one (IX) also occurred. Hypotheses concerning the mechanism and the steric course of this reaction are given. The reaction is a general method for the stereospecific synthesis of 2,3-disubstituted 1,2,3,4,5,10-hexahydrobenzo[g]quinoxalines.     

Synthesis and Transformations of 2-Hydroxy-3-arylazo-1,4-naphthoquinones

A series of 2-hydroxy-3-arylazo-1,4-naphthoquinones were prepared by coupling of 2-hydroxy-1,4-naphthoquinone with aryldiazonium chlorides. The reactivity of the products toward electrophilic and nucleophilic agents was studied. In reaction with o-phenylenediamine they give condensation products, the corresponding benzo[a]phenazines.     

Acylation of 2-arylamino-3-chloro-5,8-dihydroxy-1,4-naphthoquinones

2-Arylamino-3-chloro-5,8-dihydroxy-1,4-naphthoquinones reacted with acetic anhydride and benzoyl chloride in pyridine to give in succession the corresponding O-acyl derivatives at both hydroxy groups. The primary acylation products were 8-acyloxy-2-arylamino-3-chloro-5-hydroxy-1,4-naphthoquinones.     

Three different dimerizations of 2-bromo-3-methyl-1,4-naphthoquinones

Three types of dimeric naphthoquinones, which possess structurally diverse skeletons, can be prepared in one step from 2-bromo-3-methyl-1,4-naphthoquinones. 2,2'-Dimeric naphthoquinones were prepared by a one-pot Stille-type reaction via vinylstannanes. Oxepines are formed by unexpected domino reactions via 1,4-dihydroxynaphthalene species. Epoxides are formed by a Michael/Darzens reaction via the o-quinone methides.     

Photolysis of 2-piperidino- and 2-morpholino-3-methoxy-1,4-naphthoquinones

PMR and¹³C NMR spectroscopy was used to establish the structure of the primary products of the photolysis of 2-piperidino- and 2-morpholino-3-methoxy-l, 4-naph-thoquinones. A scheme for the subsequent dark transformations of these compounds is proposed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 709–713, March, 1991.     

Synthesis,photolysis, and redox properties of 2-dialkylamino-3-methoxy-1,4-naphthoquinones

A synthesis is reported for 2-dialkylamino-3-methoxy-1,4-naphthoquinones. The photolysis of these compounds in the liquid phase was studied and their halfwave potentials (E_1/2) were determined. The introduction of a methoxy group at C³ leads to a shift in the spectral absorption toward longer wavelengths, shift in E_1/2 toward positive values, and a slight change in the photolysis quantum yield. The physicochemical parameters were found to be dependent on the nature of the dialkylamino group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 657–661, March, 1990.     

Isomerization of 4-arylamino-1,2-naphthoquinones to 2-arylamino-1,4-naphthoquinones

4-Arylamino-1,2-naphthoquinones isomerize into 2-arylamino-1,4-naphthoquinones upon refluxing in acetic acid. The isomerization follows two routes via intermediate 2-hydroxy-1,4-naphthoquinone and 2-arylamino-1,4-naphthoquinone 4-N-arylimines.     

Intramolecular cyclization of 2-aryl-3-aminoacetyl-1,4-naphthoquinones to 3-benzocoumaranone derivatives

The isomerization of 2-aryl-3-(N-alkyl-N-arylamino)acetyl-1,4-naphthoquinones to 2-(N-alkyl-N-arylamino)-4-aryl-5-hydroxy-6,7-benzocoumaran-3-ones was studied. The structures of the compounds obtained were confirmed by the data from the UV, IR, mass and PMR spectra.Communication 30 from the series Synthesis and Properties of Charge-Transfer Complexes and Self-Complexes; see [1] for communication 29.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 739–745, June, 1979.     

Synthesis of 2-amino(alkylamino)-3-nitro-1,4-naphthoquinones

The reaction of 2-amino(alkylamino)-1,4-naphthoquinones with nitrating mixture in concentrated sulfuric acid leads to the formation of 2-amino(alkylamino)-3-nitro-1,4-naphthoquinones.     

5-arylethynyl-1,4-naphthoquinones

Conclusions The syntheses of a series of 5-arylethynyl-1,4-naphthoquinones were carried out by the reaction of 5-iodonaphthoquinone with substituted cuprous acetylides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2561–2565, November, 1984.     

Photolysis of 2-dialkylamino-3-amino(or alkylamino)-1,4-naphthoquinones

Using¹H and¹³C NMR spectroscopy, naphthodihydroimidazolediols were identified as the primary products of photolysis of 2-dialkylamino-3-amino(alkylamino)-1,4-naphthoquinones. Their further non-photochemical (thermal) transformations depend on their structure and on the photolysis conditions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 358–362, February, 1993.     

Gas chromatographic analysis of 1,4-naphthoquinones

Summary A gas chromatographic method is described for the analysis of 1,4-naphthoquinone derivatives in the mixtures of their isomers. The best results were obtained using 7.5% XE-60 on Chromosorb G at 180°. Quantitative determination was carried out with 1,4-naphthoquinone as the internal standard and using relative response factors or by means of the direct calibration method.