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.     

5-Substituted pyrimidine derivatives

The properties and reactivities of 4-hydroxy- and 2,4-dihydroxy-5-(β-hydroxyethyl)pyrimidines and of the products of their transformations have been studied. 4-Chloro- and 2,4-dichloro-5-(β-chloroethyl)pyrimidines have been obtained. A number of 4-alkyl(aryl)amino-5-(β-chloroethyl)pyrimidines have been synthesized, and they have been converted into derivatives of 5,6-dihydropyrrolo[2,3-d]pyrimidine.     

Isolement et identification de l'acide furfurique,nouvelle depsidone du lichen Pseudevernia furfuracea (L.) Ach

Isolation and Identification of Furfuric Acid a New Depsidone from the Lichen Pseudevernia furfuracea (L.) Ach. The structure of furfuric acid, ( 1 ), a new depsidone, isolated from the lichen Pseudevernia furfuracea (L.) Ach. has been established as 4-formyl-3,8-dihydroxy-9-(2,4-dihydroxy-5-methoxycarbonyl-3,6-dimethylbenzyl)-1,6-dimethyl-11-oxo-11H-dibenzo[b,e][1,4]dioxepin-7-carboxylic acid by spectral and chemical methods.     

Azonia polycyclic quinones,o-diazo-oxides and related products

4α-Azoniaanthracene-5,6- and 5,8-dione salts have been prepared by nitric acid oxidation of their respective diols, and are shown to function as either an electrophilic dienophile or a diene component in Diels-Alder-type reactions. Several azonia o-quinones have been treated with tosylhydrazine in methanol saturated with hydrogen chloride to give unusually stable o-diazo-oxides. A four-step dehydroxylation procedure is detailed for the conversion of .5,6-dihydroxy-4α-azonia-anthracene salts to new 5-hydroxy-4α-azoniaanthracene salts.     

Hydroxy and methoxy substituted N 1,N 4-diarylidene-S-methylthiosemicarbazone iron(III) and nickel(II) complexes

Template reactions of 2,4-dihydroxy-, 2,5-dihydroxy-, 2-hydroxy-3-methoxy- and 2-hydroxy-4-methoxy-benzaldehyde with methoxy- and hydroxy-substituted salicylaldehyde S-methylthiosemicarbazones in the presence of NiCl₂ and FeCl₃ resulted in the corresponding hydroxy- and methoxy-substituted N¹,N⁴-diarylidene-S-methylthiosemi-carbazone complexes. Characterization of the compounds, [Fe(L)Cl] and [Ni(L)], was accomplished by means of elemental analysis, conductivity and magnetic measurements, i.r. and ¹H-n.m.r. spectra. A systematic trend has been observed for the chemical shift values of the aromatic protons in the spectra of complexes.     

Synthesis and Study of Aromatic Derivatives of 5,6-Dihydro-4-pteridinol

The reaction of 4-hydroxy-5,6-diamino- and 2,5,6-triaminopyrimidines with substituted -bromoacetophenones gives aryl derivatives of 5,6-dihydro-4-pteridinols. The course of these reaction is discussed and the physicochemical characteristics of these products were studied.     

A new synthesis of 5-hydroxy-6-methyluracil

Dehydration of 5,6-dihydro-5,6-dihydroxy-6-methyl- and 5,6-dihydro-5,6-dihydroxy-1,3,6-trimethyl-uracil in 0.4 M aqueous sulfuric acid gives 5-hydroxy-6-methyl- and 5-hydroxy-1,3,6-trimethyluracil in quantitative yields. Two possible mechanisms have been examined using the mPW1k/6-311+G(2df,2pd)//mPW1k/6-31+G(d,p) method for the transformation of methylated and non-methylated 5,6-dihydro-5,6-dihydroxy-6-methyluracils into the corresponding 5-hydroxy-6-methyluracils. The first is a hydride C5-C6 shift occurring in concert with the loss of a water molecule and formation of the corresponding protonated 5,6-dihydro-5-oxo-6-methyluracils. The second is an acid-catalyzed dehydration reaction to yield 5-hydroxy-6-methyluracils. The calculations demonstrated that the second pathway was energetically most favorable.     

The reaction of 2,2,4,4-tetramethyl-1,3-cyclobutanedione with o-aminophenols,o-aminothiophenol and with aliphatic 2- and 3-hydroxy- and -mercaptoamines

Studies of the reaction of the dione dimer of dimethylketene ( 1 ) with a series of o-aminophenols and with o-aminothiophenol have been carried out. These reactions give 2-[2-(2,4-dimethyl-3-oxopentyl)]benzoxazoles and -benzothiazole, respectively. Aliphatic 2- and 3-hydroxy- and 2- and 3-mercaptoamines yield 2-substituted 2-oxazolines, 5,6-dihydro-4H-1,3-oxazines, 2-thiazolines and 5,6-dihydro-4H-1,3-thiazines.     

The synthesis of benzofuroquinolines. III. Two dihydroxybenzofuroquinolinones

Two dihydroxybenzofuroquinolinones, 3,9-dihydroxy-5H-benzofuro[3,2-c]quinolin-6-one (V) and 3,8-dihydroxy-6H-benzofuro[2,3-b]quinolin-11-one (VI), were obtained by the demethyl-cyclization of 3-(2,4-dimethoxyphenyl)-4-hydroxy-7-methoxy-1H-quinolin-2-one (IV). By the methylation with diazomethane, V gave a dimethylated compound (VII), while VI gave a trimethylated compound (VIII).     

二[4-羟基-5,6-二氢-6-烷基(芳基)-2H-吡喃-2-酮-3-]烃的合成及生物活性的研究

采用5,6-二氢-6-烷基(芳基)-2H-吡喃-2,4-二酮和醛进行缩合反应,合成了二[4-羟基-5,6-二氢-6-烷基(芳基)-2H-吡喃-2-酮-3-]烃.其结构经¹HNMR和元素分析证实.对反应条件(反应温度、反应时间)进行了探讨.生物活性初步测定表明,该类化合物具有一定的杀菌和抗烟草花叶病毒的活性.     

Synthesis of carbazomycin B by radical arylation of benzene

Iodination of 2-methoxy-3,4-dimethyl-5-nitrophenol followed by acetylation yields (6-iodo-2-methoxy-3,4-dimethyl-5-nitrophenyl) acetate. Reduction with iron and acetic acid followed by reaction with methyl chloroformate then provides N-methoxycarbonyl-3-acetoxy-2-iodo-4-methoxy-5,6-dimethylaniline. Treatment of this substance in benzene at reflux with tributyltin hydride and a catalytic quantity of diphenyl diselenide leads to the formation of N-methoxycarbonyl-3-acetoxy-2-(2,5-cyclohexadienyl)-4-methoxy-5,6-dimethylaniline which on exposure to phenylselenenyl bromide affords a phenylselenenyl tetrahydrocarbazole. Oxidation deselenation and rearomatization are achieved by heating with tert-butylhydroperoxide finally affording carbazomycin B after saponification.     

Synthesis of 5,6-Dimethylbenz[a]phenazine

5,6-Dimethylbenz[a]phenazine ( 4 ), an aza analogue of the carcinogenic 5,6-dimethylbenz-[c]acridine has been obtained by a 1,1-dehydration-rearrangement (Wagner-Meerwin type) from 5,5-dimethyl-6-hydroxy-5,6-dihydrobenz[a]phenazine ( 3 ). The alcohol 3 was obtained from the hydrogenation of the corresponding ketone 2 which was prepared in two ways: Method A, the oxidation of 5,5-dimethyl-5,6-dihydrobenz[a]phenazine ( 1 ); Method B, the hydrolysis of the 6,6-dibromo derivative 5 of 1.     

天然产物的绝对构型研究(Ⅰ)——通过比较旋光和碳谱的实验值与计算值确定酮类、内酯类和醇类化合物的绝对构型

在研究天然产物绝对构型的过程中, 筛选了系列绝对构型未鉴定的化合物, 在B3LYP/aug-cc-pVDZ//B3LYP/6-31G(d)水平上计算了它们的旋光和碳谱数据. 结果表明, 计算结果与实验数值十分符合, 从而鉴定出了这些化合物的绝对构型. 另外, 根据计算结果和早期实验报告更正了1个化合物的碳谱化学位移.     

Anthraquinones from the roots of Prismatomeris malayana

A novel anthraquinone, 1,3-dihydroxy-5,6-dimethoxy-2-methoxymethyl-9,10-anthraquinone (9) and a new natural product, 2-hydroxymethyl-1-methoxy-9,10-anthraquinone (8) were isolated from the roots of Prismatomeris malayana together with seven known anthraquinones, tectoquinone (1), 1-hydroxy-2-methyl-9,10-anthraquinone (2), rubiadin (3), rubiadin-1-methyl ether (4), 1,3-dihydroxy-5,6-dimethoxy-2-methyl-9,10-anthraquinone (5), nordamnacanthal (6), and damnacanthal (7). Their structures were determined on the basis of spectroscopic data. Some of the anthraquinones were tested for anticancer, antifungal, and antimalarial activities.     

2-Phenyl-4-quinolinone Alkaloids from Casimiroa edulis Llave et Lex (Rutaceae)

 Three new 4-quinolinone alkaloids (5,6-dimethoxy-2-(3-methoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(3,4-dimethoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(2,5,6-trimethoxyphenyl)-1H-quinolin-4-one) were isolated from the leaves of Casimiroa edulis Llave et Lex (Rutaceae) cultivated in Egypt. Their structures were determined by UV/Vis, IR, ¹H and ¹³C NMR, and EI mass spectroscopy. The alkaloids were also detected in the kernels of the seeds.     

Reactivity of acyclic (pentadienyl)iron(1+) cations: synthetic studies directed toward the frondosins

A short, 4-step route to the scaffold of frondosin A and B is reported. The [1-methoxycarbonyl-5-(2',5'-dimethoxyphenyl)pentadienyl]Fe(CO)(3)(+) cation was prepared in two steps from (methyl 6-oxo-2,4-hexadienoate)Fe(CO)(3). Reaction of this cation with isopropenyl Grignard or cyclohexenyllithium reagents affords (2-alkenyl-5-aryl-1-methoxycarbonyl-3-pentene-1,5-diyl)Fe(CO)(3) along with other addition products. Oxidative decomplexation of these (pentenediyl)iron complexes, utilizing CuCl(2), affords 6-aryl-3-methoxycarbonyl-1,4-cycloheptadienes via the presumed intermediacy of a cis-divinylcyclopropane.     

Halogenation of N-Substituted p-Quinonimines and p-Quinone Oxime Esters: II. Chlorination and Bromination of 4-Aroyl(arylsulfonyl)oxyimino-2-methyl-2,5-cyclohexadienones

Halogenation of 4-aroyl(arylsulfonyl)oxyimino-2-methyl-2,5-cyclohexadienones yields Z,E-isomeric 4-aroyl(arylsulfonyl)oxyimino-5,6-dihalo-2-methyl-2-cyclohexenones and (E)-4-aroyl(arylsulfonyl)oxyimino-5,6-dihalo-6-methyl-2-cyclohexenones. Further chlorination leads to formation of (Z,E)-4-aroyl(arylsulfonyl)oxyimino-2,5,6-trichloro-6-methyl-2-cyclohexenones.     

Retro-ene reactions in heterocyclic synthesis. II. A facile synthetic method for 4-hydroxy-2-pyridones

Schiff's bases 1 derived from ketones and t-butylamine reacted with diphenyl malonate, diphenyl methyl-malonate and diphenyl phenylmalonate to give 4-hydroxy-2-pyridones 4–6 . Schiff's bases b on reaction with trimethyl methanetricarboxylate afforded 4-hydroxy-3-methoxycarbonyl-2-pyridones 12 .     

Xanthones from stems of Hypericum chinense

Six new xanthones, 4,6-dihydroxy-2,3-dimethoxyxanthone (1), 2,6-dihydroxy-3,4-dimethoxyxanthone (2), 6-hydroxy-2,3,4-trimethoxyxanthone (3), 3,6-dihydroxy-1,2-dimethoxyxanthone (4), 4,7-dihydroxy-2,3-dimethoxyxanthone (5), and 3,7-dihydroxy-2,4-dimethoxyxanthone (6) were isolated from the stems of Hypericum chinense, together with four known xanthones. Their structures were established based on spectroscopic studies.     

3-Furylchromones

-[2-(5-Methoxycarbonyl)furyl]-2,4-dihydroxy- and 2,4,6-trihydroxyacetophenones were obtained by the condensation of polyphenols with (2-methoxycarbonyl-5-furyl)acetonitrile. 7-Acetoxy- and 5,7-diacetoxy-2-methyl-3-[2-(5-methoxycarbonyl)furyl]chromones were obtained from them by reaction with acetic anhydride in the presence of triethylamine and were subsequently deacylated to 7-hydroxy and 5,7-dihydroxy compounds. 7-Hydroxy- and 5,7-dihydroxy-2-ethoxycarbonyl-3-[2-(5-methoxycarbonyl)furyl]chromones were obtained from the indicated acetophenones by reaction with ethoxalyl chloride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1317–1320, October, 1972.