Potassium fluoride-promoted reaction of (2-chloro-2-nitroethenyl)benzenes with 1,3-dicarbonyl compounds. A general synthesis of 6,6-dimethyl-2-nitro-3-phenyl-3,5,6,7-tetrahydro-4(2H)benzofuranones and some analogs

A convenient procedure to prepare in good yields 6,6-dimethyl-2-nitro-3-phenyl-3,5,6,7-tetrahydro-4(2H)-benzofuranones starting from (2-chloro-2-nitroethenyl)benzenes and 5,5-dimethyl-1,3-cyclohexanedione in the presence of potassium fluoride is reported. This method also proved efficient with other 1,3-dicarbonyl compounds, and has been successfully extended to 1,3-cyclohexanedione, 2,5-pentanedione, dibenzoylmethane and ethyl acetoacetate.     

KF-Al_2O_3催化下达米酮与查尔酮的麦克尔加成反应

5，5-二甲基-1，3-环己二酮（达米酮）、1，3-二芳基-2-丙烯-1-酮（查尔酮 ）在KF-Al_2O_3催化下，在DMF中进行麦克尔加成反应，生成产物为1，3-二芳基- 3-（5，5-二甲基-3-羟基-2-环己烯-1-酮-2-基）-1-丙酮，产率良好。     

KF-Al2O3催化下3-芳基-3-(5，5-二甲基-3-羟基-2-环己烯-1-酮-2-基)丙酰胺衍生物的合成

芳醛、5，5—二甲基—1，3—环己二酮、丙二酸亚异丙酯、芳胺在KF-Al2O3催 化下，在DMF中反应生成3—芳基—3—(5，5—二甲基—3—羟基—2—环己烯—1— 酮—2—基)丙酰胺衍生物，产率良好。     

Electrochemical oxidation of 2,3-dimethylhydroquinone in the presence of 1,3-dicarbonyl compounds

The electrooxidation of 2,3-dimethylhydroquinone (1) has been studied in the presence of 2-phenyl-1,3-indandione (3a), 3-hydroxy-1H-phenalen-1-one (3b), and 2-chloro-5,5-dimethyl-1,3-cyclohexanedione (3c) as CH acid nucleophiles in water/acetonitrile (85/15) solution, using cyclic voltammetry and controlled-potential coulometry. The results indicate that p-benzoquinone, generated by electrochemically driven oxidation of the 2,3-dimethylhydroquinone (1), is scavenged by 3a-c, to give related products (5a, 9b, 8c) via various electrochemical mechanisms. The electrochemical syntheses of 5a, 9b, and 8c have been successfully performed in one-pot in an undivided cell using an environmentally friendly method with high atomic economy.     

无外加催化剂条件下芳香醛与活性亚甲基化合物的缩合反应和迈克尔加成反应

在DMF溶剂中，不外加催化剂使芳香醛(1)与2,2-二甲基-1,3-二氧六环-4,6-二酮(2)发生缩合反应生成2,2-二甲基-5-芳亚甲基-1,3-二氧六环-4,6-二酮(3a～f)。在同样条件下，芳香醛与5,5-二甲基-1,3-环己二酮(4)则发生缩合和迈克尔加成反应生成2,2'-芳亚甲基双(3-羟基5,5-二甲基-2-环己烯-1-酮)(5a～h)。用单晶X-射线分析法确定了产物5b的晶体结构。     

2-Substituted 5-oxo-5,6,7,8-tetrahydroquinazolines

Twenty novel 2-substituted 5-oxo-5,6,7,8-tetrahydroquinazolines in reactions of 2-formyl-1,3-cyclohexanedione and its 5,5-dimethyl- and 5-phenyl derivatives with 4-chloro- and 4-carbonylaminobenzamidines, 3- and 4-carbamidinopyridines, 2-carbamidinopyrazine, 2-carbamidino-5-trifluoromethylpyridine, 1-carbamidinopyrrolidine, 4-carbamidinomorpholine, and 1-carbamidino-3,5-dimethylpyrazole have been obtained.Riga Technical University, Riga LV-1658, Latvia; e-mail: marina@osi.lv. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 212–26, February, 2000.     

2-(1-Isonicotinoylhydrazinoalkylidene)-5,5-dimethyl-1,3-cyclohexanediones and their polychromism. A new type of compound with intramolecular charge transfer through the hydrazonocarbonyl bridge

The product of condensation of 2-formyldimedone with the hydrazide of isonicotinic acid, namely 2-isonicotinoylhydrazinomethylene-5,5-dimethyl-1,3-cyclohexanedione, has been obtained in three forms — red, colorless, and yellow — which with methyl iodide give one and the same iodide 2-[N-(1-methyl-4-pyridiniumcarbonyl)hydrazinomethylene]-5, 5-dimethyl-1, 3-cyclohexanedione. On the basis of UV spectra and x-ray structure analysis of this betaine and also the dark-red iodide of N-(4-diethylaminobenzal)-N-(1-methyl-4-pyridiniumcarbonyl)hydrazine, it has been shown that intramolecular charge transfer in these linear molecules proceeds along the system of bonds D:-RC=N-NH-CO-A through the hydrazonocarbonyl bridge, which does not interrupt the conjugation chain. The existence of colored forms of the 2-isonicotinoylhydrazinomethylene-5,5-dimethyl-1,3-cyclohexanedione can be explained by an admixture of the betaine form.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 489–498, April, 1993.     

New Practical Synthesis of Tetrahydronquinolin-2,5-diones

A series of 4,6,7,8-tetrahydro-2,5-(1H,3H)-quinolinediones was prepared from ethyl-2-cyanoacetate, aromatic aldehydes and 1,3-cyclohexanedione or 5,5-dimethyl-1,3-cyclohexanedione by two steps, the yields were moderate to excellent. This method is a new practical promising green strategy to synthesize tetrahydronquino-lin-2,5-diones.     

1-(2-Quinoxalyl)-, 1-[3,5-Di(trifluoromethyl)phenyl]-, 1-(2-Carboxyphenyl)-, and 1-Ethoxycarbonyl-4-oxo-4,5,6,7-tetrahydroindazoles

The corresponding 1-(2-quinoxalyl)-, 1-[3,5-di(trifluoromethyl)phenyl]-, and 1-ethoxycarbonyl-3-methyl-4-oxo-4,5,6,7-tetrahydroindazoles have been obtained from reactions of 2-acetyl-1,3-cyclohexanedione, its 5,5-dimethyl and 5-(2-furyl) derivatives, with 2-hydrazinoquinoxaline, 3,5-di(trifluoromethyl)phenylhydrazine, and ethoxycarbonylhydrazine. On interaction with ethoxycarbonylhydrazine the intermediate 2-[1-(-ethoxycarbonyl)hydrazino]ethylidene-1,3-cyclohexanediones were also isolated. From the potassium salt of 2-formyldimedone and 2-carboxyphenylhydrazine hydrochloride, 2-(2-carboxyphenyl)hydrazinomethylene-5,5-dimethyl-1,3-cyclohexanedione was obtained, the cyclization of which in ethanol in the presence of HCl led to 1-(2-carboxyphenyl)- and 1-(2-ethoxycarbonylphenyl)-6,6-dimethyl-4-oxo-4,5,6,7-tetrahydroindazole.     

Reactions of Bisazomethines of the Naphtalene Series with 1,3-Diketones

Bisazomethines prepared from aromatic dialdehydes and 2-naphthylamine were for the first time reacted with the following diketones: 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 5-phenyl-1,3-cyclohexanedione, indandione, and 2,2-dimethyl-1,3-dioxane-4,6-dione was studied. The reactions with 1,3-diketones of the cyclohexane series yield benzophenanthridine derivatives. The reactions with indandione, depending on conditions, give either bisarylideneindandiones or bisdihydrobenzo[f]indenoquinoline. As evidenced by the ^13C NMR and IR spectra, in the case of biphenyl-4,4'-dicarbaldehyde bis[N-(2-naphthyl)imine] and 2,2-dimethyl-1,3-dioxane-4,6-dione, 4,4'-bis(3-oxo-1,2,3,4-tetrahydrobenzo[f]quinolin-1-yl)biphenyl is formed.     

Mechanistic studies in the attempted synthesis of 5,5-dimethyl-2-isopropylidene-1,3-cyclohexanedione

In contrast to the corresponding cyclopentanedione derivative, 5,5-dimethyl-2-isopropyl-2-phenylsulfinyl-1,3-cyclohexanedione (3) does not undergo the expected cis-elimination of phenylsulfenic acid on warming in CH₂Cl₂ to afford the title compound 1, but instead gives an equimolar mixture of 5,5-dimethyl-2-(1 ′-isopropyl-4′,4′-dimethyl-2′,6′-dioxocyclohexyl)-2-isopropyl-1, 3-cyclohexanedione (9) and S-phenyl benzenethiosulfonate (10). These products result from dimerization of the 4,4-dimethyl-1-isopropyl-2,6-dioxocyclohexylradical (7) andthephenylsulfinyl radical (8), respectively. Diploma Thesis, University of Hamburg, 1990.     

Synthesis of N-substituted acridinediones and polyhydroquinoline derivatives in refluxing water

Acridinediones were synthesized by the one-pot Hantzsch condensation of an aromatic aldehyde, 5,5-dimethyl-1,3-cyclohexanedione, and aniline/4-methylaniline in re?uxing water. This method has then been extended to the four-component reaction of an aromatic aldehyde, 5,5-dimethyl-1,3-cyclohexanedione, ethyl acetoacetate and ammonium acetate for the synthesis of polyhydroquinoline derivatives. This is an environmentally friendly and efficient procedure providing good to excellent yields.     

A convenient one-pot synthesis of substituted 2-pyrone derivatives

2-Pyrone derivatives were prepared in a one step procedure from readily available (chlorocarbonyl)phenyl ketene and 1,3-diketones such as 2,4-pentanedione, 1,3-diphenyl-1,3-propanedione, 1-phenyl-1,3-butanedione, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-dimethyl-pyrimidine-2,4,6-trione and ethyl 2,4-dioxopentanoate. A mechanism is presented to account for the formation of the products. This method provides an easy route to prepare 3,4,5,6-tetrasubstituted 2-pyrones in good to excellent yields and in a short experimental time.     

A Convenient Synthesis of 3-Aryl-3-(5,5-dimethyl-3-hydroxy-2-cyclohexene-1-one-2-yl) Propanic Esters Catalyzed by KF-Alumina

A series of 3-aryl-3-(5,5-dimethyl-3-hydroxy-2-cyclohexene-1-one-2-yl) propanic esters were synthesized by reaction of aromatic aldehydes, 5,5-dimethyl-1,3-cyclohexanedione and isopropylidene malonate in alcohols catalyzed by KF-Al₂O₃. The structure of 4a was determined by X-ray analysis.     

在离子液体中4-芳基-5-氧代-1,4,5,6,7,8-六氢喹啉-3-羧酸酯的合成

以芳醛、氨基巴豆酸酯和5,5-二甲基-1,3-环己二酮或1,3-环己二酮为原料在离子液体[bmimBF₄]中合成了一系列4-芳基-5-氧代-1,4,5,6,7,8-六氢化喹啉-3-羧酸酯, 该方法具有产率高、环境友好等特点. 产物的结构通过红外光谱和核磁共振氢谱进行表征, 并通过X单晶衍射分析进一步证实产物的结构.     

2,2,7,7-四甲基-5,6-二氧代-9-(2-氯苯基)-10-(4-甲基苯基)-9,10-二氢-2H-吖啶的合成和晶体结构

标题化合物2,2,7,7-四甲基-5,6-二氧代-9-(2-氯苯基)-10-(4-甲基苯基)-9,10-二氢-2H-吖啶(C30H32ClNO2,Mr=474.02)是由邻氯苯甲醛和5,5-二甲基-1,3-环己二酮和对甲基苯胺以乙二醇作溶剂在微波辐射下而得到的。结构通过单晶X-射线衍射分析确定,其晶体属于单斜晶系,空间群P21/c,a=12.048(3),b=11.044(2),c=19.989(5)?b=101.42(2),Z=4,V=2607(1)3,Dc=1.208g/cm3,m(MoKa)=0.173mm-1,F(000)=1008,R=0.0450,wR=0.0869。X-射线衍射分析表明:原子C(8),C(13),C(14),C(15),C(20)和N形成1个六员环,采用船式构象,六员环C(8)~C(13)和C(15)~C(20)采用半椅式构象。     

Solid-state radical reactions of 1,3-cyclohexanediones with in situ generated imines mediated by manganese(III) acetate under mechanical milling conditions

Under solid-state conditions, manganese(iii) acetate-mediated radical reactions of 1,3-cyclohexanedione and 5,5-dimethyl-1,3-cyclohexanedione with in situ generated imines proceeded efficiently by mechanical milling at room temperature and good to excellent yields were achieved.     

Synthesis of New Water-Soluble Cholesterol Derivatives

L-Proline has been used as an organocatalyst for an efficient synthesis of 1,8-dioxo-octahydroxanthenes by treatment of aldehydes (aromatic, heteroaromatic, and aliphatic) with 5,5-dimethyl-1,3-cyclohexanedione. Three new compounds have been prepared.     

Reusable silica-bonded S-sulfonic acid catalyst for three-component synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes and 2-amino-4H-pyrans in aqueous ethanol

Silica-bonded S-sulfonic acid (SBSSA)-catalyzed, facile, one-pot, three-component coupling of 5,5-dimethyl-1,3-cyclohexanedione (dimedone) or 5,5-dimethyl-1,3-cyclohexanedione, aromatic aldehydes, and malononitrile at reflux temperature is described for preparation of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene derivatives. 2-Amino-3-cyano-6-methyl-4-phenyl-4H-pyran-5-ethylcarboxylate derivatives can also be prepared in good yield under the same experimental conditions by use of ethyl acetoacetate, aldehydes, and malononitrile. The catalyst, silica-bonded S-sulfonic acid, was reused and recycled without any loss of activity or product yield.     

水介质中5-氧代-4-芳基-1,4,5,6,7,8-六氢喹啉-3-羧酸甲酯的合成

在水介质中有三乙基苄基氯化铵(TEBA)存在下, 以芳醛、β-氨基巴豆酸甲酯、5,5-二甲基-1,3-环己二酮(或1,3-环己二酮)三组分混合反应, 一步合成了5-氧代-4-芳基-1,4,5,6,7,8-六氢喹啉-3-羧酸甲酯. 该反应具有操作简单、产率高、环境友好的优点.