Revision of the structure of cuculoquinone to 3,3′-bis(6-ethyl-2,5,7,8-tetrahydroxy-1,4-naphthoquinone) and confirmation of the proposed structure by synthesis

A reinvestigation of cuculoquinone, previously isolated from the lichen Cetraria cucullata, led to a revision of the proposed structure to 3,3′-bis(6-ethyl-2,5,7,8-tetrahydroxy-1,4-naphthoquinone). The new structure was confirmed by synthesis.     

Spinazarin and ethylspinazarin,pigments of the sea urchin <Emphasis Type="Italic">Scaphechinus mirabilis</Emphasis>

2,3,5,8-Tetrahydroxy-1,4-naphthoquinone (spinazarin) and 6-ethyl-2,3,5,8-tetrahydroxy-1,4-naphthoquinone (ethylspinazarin) were first isolated from the sea urchin Scaphechinus mirabilis. The structures of spinazarins were established based on analysis of spectroscopic data. A preparative synthetic route to ethylspinazarin was proposed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 788–791, April, 2007.     

The chemistry of naphthazarin derivatives

Direct oxidation of naphthazarin with manganese dioxide in conc. H₂SO₄ was found to be a simple and effective method for the synthesis of mompain. For Part 3, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1019–1021, May, 1999.     

Formation of substituted 6-hydroxy-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridine upon photochemical transformation of nifedipine

Long-term exposure of nifedipine to daylight in ethanol gives 2,2"-bis[3,5-bis(methoxycarbonyl)-2,6-dimethylpyridin-4-yl]azoxybenzene and 6-hydroxy-1-methoxycarbonyl-2,4-dimethyl-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridine as the major products.     

两种含杂环的氨基萘醌化合物的合成

以2,3-二氯-1,4-萘醌为主要原料,分别与吗啡啉和糠胺在一定条件下反应生成2种含杂环的氨基萘醌类化合物。2,3-二氯-1,4-萘醌与吗啡啉及2,3-二氯-1,4-萘醌与糠胺物质的量比均为1∶2,反应温度为60℃,溶剂为乙醇。2,3-二氯-1,4-萘醌与吗啡啉反应时间为1 h,产物2-氯-3-吗啡啉基萘-1,4-二酮(a)收率为93.5%;2,3-二氯-1,4-萘醌与糠胺反应时间为4 h,产物N~2,N~3-二(2-呋喃甲基)-1,4-二((2-呋喃甲基)亚胺)-1,4-二氢化萘-2,3-二氯化铵(d)收率为46.7%。对产物进行IR、Uv、MS和H-NMR等分析表征。     

Reaction of 3,3-dichloropentane-2,4-dione with aromatic aldehydes under the conditions of Darzens reaction

3,3-Dichloropentane-2,4-dione reacts with aromatic aldehydes under the conditions of Darzens reaction to give 4-acetoxy-4-aryl-3,3-dichlorobutan-2-ones, the products of insertion into the -C-C bond. The reaction of ethyl dichloroacetylacetate with benzaldehyde yields a derivative of tricyclo[5.1.0.0^3,5]octane, rather than 2,6-bis(1-chlorobenzylidene)cyclohexane-1,4-dione, as the by-product.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1294–1298, July, 1995.     

7-Substituted 8-vinyl-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-diones and their broncholytic activity

Summary Alkylation of 8-vinyl-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione (1) with alkyl halides inDMF in the presence of potassium carbonate, or alternatively, alkylation of its sodium salt (2) with alkyl iodide or hydroxyalkyl iodide afforded the 7-alkyl- or 7-(-hydroxyalkyl)-8-vinyl-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-diones3. 2-Substituted oxiranes reacted with1 catalyzed by2 or Triton B to yield 7-(2-hydroxyalkyl)-8-vinyl-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-diones4. Compounds3 and4 were tested for broncholytic activity. The most effective derivatives were3c and4b.

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7-Substituierte 8-Vinyl-1,3-dimethyl-3,7-dihydro-1H-purin-2,6-dione und ihre broncholytische Wirkung

Zusammenfassung Alkylierung von 8-Vinyl-1,3-dimethyl-3,7-dihydro-1H-purin-2,6-dion (1) mit Halogenalkanen in Gegenwart von Kaliumkarbonat inDMF oder Alkylierung seines Natrium-Salzes (2) mit Iodalkanen beziehungsweise Iodalkanolen führte zu den 7-Alkyl- bzw. 7-(-Hydroxyalkyl)-8-vinyl-1,3-dimethyl-3,7-dihydro-1H-purin-2,6-dionen3. 2-Substituierte Oxirane reagierten mit Verbindung1 unter Katalyse durch2 oder Triton B zu den entsprechenden 7-(2-Hydroxyalkyl)-derivaten4. Die Substanzen3 und4 wurden auf ihre broncholytische Wirkung geprüft. Die höchste Aktivität wurde bei den Derivaten3c und4b festgestellt.

     

Chemistry of naphthazarin derivatives. 8. Determination of structures of substituted 2-hydroxy-6(7)-methoxynaphthazarins and 7(8)-hydroxypyranonaphthazarins by IR spectroscopy

A set of substituted 2-hydroxy-6(7)-methoxynaphthazarins and 7(8)-hydroxypyranonaphthazarins were synthesized. The IR spectra of 2-hydroxy-6-methoxynaphthazarins and 7-hydroxypyranonaphthazarins, on the one hand, and of 2-hydroxy-7-methoxynaphthazarins and 8-hydroxypyranonaphthazarins, on the other hand, have the characteristic nonoverlapping intervals of stretching vibration frequencies of the -hydroxy groups. These regularities confirm the structures of cristazarin and 6-methylcristazarin, which are metabolites of lichen Cladonia cristatella.     

Structure and Spectroscopic Characteristics of N,N′-bis(2-Hydroxy-3-methoxyphenylmethylidene)2,6-pyridinediamine

The Schiff base N,N-bis(2-hydroxy-3-methoxyphenylmethylidene)-2,6-pyridinediamine has been synthesized and characterized in the solid state and in solution using X-ray analysis, IR, UV/Vis, and NMR spectroscopy. Crystal data: C₂₁H₁₉N₃O₄, M _r = 377.39, orthorhombic, space group Pnc2, a = 4.9288(8), b = 8.8873(19), c = 20.870(5) Å, V = 914.19(20) ų, Z = 2, R = 0.0387, R _w = 0.0530, 1845 independent reflections, 778 with I > 2(I). There are two intramolecular hydrogen bonds O—H-N between the hydroxyl and imino groups of 2.622(3) Å. The enolimine form is found in the solid state and is also the predominant tautomeric form in solution. Comparison of the title compound with the structurally related N,N-bis(salicylidene)-2,6-pyridinediamine and N,N-bis(salicylidene)-2,3-pyridinediamine is given.     

1,1,3,3,3-Pentafluoro-2-pentafluorophenyl-1,2-epoxypropane and trimethylphosphite: unusual 1,4-dioxan-2,5-dione ring formation

1,1,3,3,3-Pentafluoro-2-pentafluorophenyl-1,2-epoxypropane 1 reacted with trimethylphosphite giving two diastereomers, (Z)- and (E)-3,6-bis(trifluoromethyl)-3,6-bis(pentafluorophenyl)-1,4-dioxan-2,5-dione 2a, b in a 1:1 ratio, cyclodimerisation product of the intermediately generated α-lactone 4. Compounds 2a, b were hydrolysed to furnish 3,3,3-trifluoro-2-hydroxy-2-(2,3,4,5,6-pentafluorophenyl)propionic acid 5.     

Free radical formation during ethylbenzene oxidation catalyzed by cetyltrimethylammonium bromide

The dimer of 2,2"-bis[2-(p-dimethylaminophenyl)indane-1,3-dione] and -tocopherol were used as free radical acceptors in a study of the kinetic regularities of free radical formation during ethylbenzene oxidation by molecular oxygen at 60 °C. The reaction initiated by the -phenylethyl hydroperoxide—cetyltrimethylammonium bromide (CTAB) catalytic system, which generates free radicals. The oxidation kinetics was analyzed using computer simulation.     

Synthesis of new heterocycles by oxidation of functionalized cyclic derivatives of bis(2-chlorovinyl) sulfide and selenide

Oxidation of 4-substituted 2,6-bis[(E)-chloromethylidene]thiomorpholine with hydrogen peroxide in a mixture of chloroform with acetic acid afforded the corresponding 4-R-2,6-bis[(E)-chloromethylidene]-thiomorpholine 1-oxide. The results of oxidation of bis[(E)-chloromethylidene]-1,4-dichalcogenanes under analogous conditions depended on the chalcogen nature and its position in the ring. The reaction of 2,6-bis[(E)-chloromethylidene]-1,4-dithiane gave 2,6-bis[(E)-chloromethylidene]-1,4-dithiane-1,1,4,4-tetraone, whereas 3,5-bis[(E)-chloromethylidene]-1,4-thiaselenane-1,1-dione was unexpectedly obtained from 3,5-bis[(E)-chloromethylidene]-1,4-thiaselenane. 2,6-Bis[(E)-chloromethylidene]-1,4-thiaselenane and 2,6-bis[(E)-chloromethylidene]-1,4-diselenane decomposed under the oxidation conditions.     

Regiospecificity in the reaction of 2,3-dichloronaphthazarins with azide anions. Synthesis of echinamine A—a metabolite produced by the sea urchin Scaphechinus mirabilis

It was found that 6-hydroxy- and 6-alkoxy-2,3-dichloronaphthazarins react smoothly with sodium azide in methanol to produce the corresponding 2-azido derivatives as single regioisomers. We have explored the utility of this reaction for the synthesis of echinamine A (3-amino-7-ethyl-2,5,6,8-tetrahydroxy-1,4-naphthoquinone)—the first marine aminated hydroxynaphthazarin, a metabolite of the sea urchin Scaphechinus mirabilis (Agassiz).     

Synthesis and photonics of ketocyanine dyes, 2,6-bis(4-dimethylaminoalka-1,3-dienyl)-4H-pyran-4-ones and ethoxytridecamethine salts based on them

The reactions of β-dimethylaminoacrolein aminals with 2,6-dimethyl-γ-pyrone lead to 2,6-bis(4-dimethylaminoalka-1,3-dienyl)-4H-pyran-4-ones, whose alkylation affords ethoxytridecamethine salts. The spectral and fluorescence properties of the synthesized compounds were studied. Their absorption spectra are unusual; along with the long-wavelength band in the visible spectral region, they contain a much more intense short-wavelength band in the near UV region. This pattern of the absorption spectra is explained in terms of the model of chromophore interaction, assuming an acute angle between the chromophore “halves” of the polyene chain of the dye molecule. The central pyran ring in the ethoxytridecamethine salts can hamper conjugation in the polymethine chain. Thermochromism of 2,6-bis(4-dimethylaminoalka-1,3-dienyl)-4H-pyran-4-ones (the long-wavelength shift of the absorption spectra on cooling of the solutions) is observed; only the long-wavelength absorption band undergoes a pronounced thermochromic shift. The introduction of methyl or phenyl substituents into the polyene chains of substituted 4H-pyranones decreases the fluorescence quantum yield. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1340–1345, July, 1999.     

Facile synthesis of (±)-2,6-dimethyloctan-1-ol formate,the biologically active analog of the smaller flour beetle aggregation pheromone,from 1-allyloxy- and 1-benzyloxy-2,6-dimethyl-2,7-octadienes,the telomers of isoprene with allyl and benzyl alcohols

A careful investigation of the telomerization of isoprene with allyl, benzyl, 2-chloroethyl and methyl alcohols on -allylpalladium complex catalysts was carried out. The structures of the obtained telomers were determined by¹H NMR spectroscopy. 1-Alkoxy-2,6-dimethyl-2,7-octadiene is a predominant telomer. 2,6-Dimethyloctan-1-ol, which reacts with HCOOH to give (±)-2,6-dimethyloctan-1-ol formate in high yield, was obtained from 1-allyloxy- and 1-benzyloxy-2,6-dimethyl-2,7-octadienes by the removal of allyl and benzyl protective groups and by the hydrogenation of double bonds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1539–1543, August, 1995.     

Synthesis of 2-(3-amino-2-oxoindolin-3-yl)-3-hydroxynaphthalene-1,4-dione derivatives via a one-pot,three-component reaction under catalyst-free conditions

A concise, facile and straightforward synthetic method has been described for the synthesis of 2-(3-amino-2-oxoindolin-3-yl)-3-hydroxynaphthalene-1,4-dione derivatives by a one-pot, three-component reaction of isatins, 2-hydroxy-1,4-naphthoquinone and ammonium acetate under catalyst-free conditions in ethanol. This protocol becomes highly efficient due to its mild reaction conditions, operational simplicity, and overall good to excellent yields (80–99%).     

Synthesis of 1,2-bis(methoxyamino)cycloalkanes from alicyclic 1,2-bis(hydroxyamines)

Derivatives of 1,4-dihydroxypiperazine-2,3-dione were obtained by reaction of cis-1,2-bis(hydroxyamino)cycloalkanes with diethyl oxalate. Their alkylation with CH₂N₂ or Mel afforded 1,4-dimethoxypiperazine-2,3-diones. Hydrolysis of the latter gave 1,2-bis(methoxyamino)cycloalkanes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 925–929, April, 1996.     

Simons electrochemical fluorination of substituted homopiperazines(hexahydro-1,4-diazepines) and piperazines

Simons electrochemical fluorination (ECF) of 1,4-dimethyl-1,4-homopiperazine, methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine was studied. For comparison, ECF of three piperazines with a N-(methoxycarbonylmethyl) group(s) was also studied. ECF of 1,4-dimethyl-1,4-homopiperazine gave a low yield of corresponding perfluoro(1,4-dimethyl-1,4-homopiperazine) together with perfluoro(2,6-diaza-2,6-dimethylheptane) as the major product. Corresponding perfluoro(homopiperazines) with mono- and/or di-(fluorocarbonyldifluoromethyl) groups [CF₂C(O)F] at the 1- and/or 4-position were formed in low yields from methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine, respectively. These new seven-membered perfluoro(1,4-dialkyl-1,4-homopiperazines) were accompanied by the formation of mono- and/or di-basic linear perfluoroacid fluorides resulting from the CC bond scission at the 2- and 3-positions of the ring. From mono- and/or di-N-(methoxycarbonylmethyl)-substituted piperazines, corresponding perfluoropeperazines having the acid fluoride group(s) were formed in low yields.     

The chemistry of naphthazarine derivatives

Based on IR and¹H and¹³C NMR spectroscopic studies, the oxidation product of echinochrome with Ag₂O was assigned the structure of 2,3-epoxy-7-ethyl-2,3-dihydro-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone. For part 4, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1607–1609, August, 1999.     

2,6-Bis[(o-hydroxy)phenyliminomethyl]-1-hydroxybenzene as a reagent for the selective spectrofluorimetric determination of aluminium

A spectrofluorimetric method for the determination of aluminium at ng/ml level has been developed. The method is based on the formation of a fluorescent 11 complex between Al(III) and 2,6-bis[(o-hydroxy)phenyliminomethyl]-1-hydroxybenzene at an apparent pH of 5.0 in an aqueous-ethanol medium (70% v/v ethanol). The influence of reaction variables is discussed. The range of concentration of the method is 1.0–10.0 ng/ml aluminium, the relative standard deviation 1.5% and the limit of detection 0.1 ng/ml. The advantages of the proposed method include high sensitivity and selectivity. The method has been applied to the determination of aluminium in natural waters.