Vinylphosphonium Salt Mediated One-Pot Stereoselective Synthesis of Dialkyl 3,3-Diacetyl-3 a -hydroxy-8-oxo-2,3,3 a ,8-tetrahydrocyclopenta-[ a ]indene-1,2-dicarboxylates

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine (or tributylphosphine) and dialkyl acetylenedicarboxylates by acetylacetone leads to sterically congested phosphorus ylides, which undergo an intermolecular Wittig reaction with ninhydrin and concomitant annulation in CH 2 Cl 2 at room temperature to produce dialkyl 3,3-diacetyl-3 a -hydroxy-8-oxo-2,3,3 a ,8-tetrahydrocyclopenta[ a ]indene-1,2-dicarboxylates in fairly high yields.     

Silica Gel Catalyzed Stereoselective Conversion of Dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to Dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 1-hydroxy-2-acetonaphthone leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates. Silica gel was found to catalyze conversion of dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in solvent-free conditions at 90°;C in fairly good yields.     

Vinylphosphonium Salt Mediated Facile Synthesis of Trialkyl 4-(2-Quinolyl)-1-cyclobutene-1,2,3-tricarboxylates and Dialkyl 3-Ethoxy-4-oxo-5-(2-(1H)-quinolinylidene)-2-cyclopentene-1,2-dicarboxylates

Summary.  The reactive 1:1 intermediate produced in the reaction between dialkyl acetylenedicarboxylates and triphenylphosphine was trapped by ethyl 3-(1,2-dihydroquinoline-2-ylidene)-pyruvate to yield the isomeric dialkyl 3-ethoxy-4-oxo-5-(2-(1H)-quinolinylidene)-2-cyclopentene-1,2-dicarboxylates and trialkyl 4-(2-quinolyl)-1-cyclobutene-1,2,3-tricarboxylates in nearly 4:1 ratio. Received April 3, 2001. Accepted (revised) May 22, 2001     

Introduction of a Novel Reaction of Triacetylmethane: One-Pot Synthesis of Dialkyl-2-(3,1-hydroxyethylidene-2,4-pentanedione-3-yl)-3-(triphenylphosphoranylidene)-butanedioate

Protonation of reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylate by 3-(1-hydroxyethylidene)-2,4-pentanedione leads to vinyl phosphonium salts, which undergo Michael addition with the conjugate base of CH-acid to produce the title compounds in high yield.     

离子液体中脂肪酶催化拆分外消旋烯丙酮醇反应

 以离子液体为溶剂,考察了溶剂类型、水活度、温度、 pH值和共溶剂等因素对脂肪酶催化拆分外消旋烯丙酮醇(R,S)-4-羟基-3-甲基-2-(2-丙烯基)-2-环戊烯-1-酮反应的影响,并与常用于外消旋烯丙酮醇拆分的有机溶剂乙酸乙烯酯进行了比较. 结果表明,在离子液体［bmim］PF6中脂肪酶的催化性能较好,酶初始反应速率为18.48 μmol/(g·min), 半衰期为74.53 h, 高于在乙酸乙烯酯中的相应值(9.18 μmol/(g·min)和64.29 h). 但离子液体中拆分反应的转化率低于在乙酸乙烯酯中的转化率,可以通过向离子液体中补加酰基供体来提高外消旋烯丙酮醇的转化率. 两种反应介质中最佳酶反应条件均为水活度0.17, 温度40 ℃和pH=7, 但加入共溶剂后,离子液体中脂肪酶催化拆分外消旋烯丙酮醇的效率降低,而在乙酸乙烯酯中则有所提高.     

Triphenylphosphine Mediated Efficient Synthesis of 4-Substituted-1-methyl-2,5-dioxo-3-imidazolines

Summary.  Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reaction between 1-methylparabanic acid (1-methylimidazoline-2,4,5-trione) and dialkyl acetylenedicarboxylates in the presence of triphenylphosphine. These ylides exist in solution as a mixture of two geometric isomers. This is due to the restricted rotation around the carbon–carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group. These ylides undergo smooth intramolecular Wittig reaction followed by an electrocyclic ring opening to produce dialkyl (E)-2-(1-methyl-2,5-dioxo-3-imidazolin-4-yl)-but-2-enedioates in good yields. Corresponding author. E-mail: isayavar@yahoo.com Received March 26, 2002; accepted (revised) April 24, 2002     

An Efficient Synthesis of Stable Sulfur-Containing Phosphoranes Derived from 1-Methylimidazole-2-thiol

Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of 1-methylimidazole-2-thiol. These sulfur-containing phosphoranes exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group. Using dibenzoylacetylene as Michael acceptor, yields 2-[1-methyl-1 H -imidazole-2-yl)sulfanyl]-1,4-diphenyl-butane-1,4-dione.     

Microwave Induced Conversion of Dialkyl 2-(3-Acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene)Butanedioates to Dialkyl 2-(3-Acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in the Presence of Silica Gel Powder in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 1-hydroxy-2-acetonaphthone leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates. Microwave was found to catalyze conversion of dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in the presence of silica gel powder in solvent-free conditions.     

Synthesis of 3-(3-Methyl-1-aryl-1H-pyrazol-5-yl)-2H-2-chromen-2-one Derivatives via a One-Pot,Three-Component Reaction

An efficient synthesis of 3-(3-methyl-1-aryl-1H-pyrazol-5-yl)-2H-2-chromen-2-one derivatives by the reaction of salicylaldehydes, 4-hydroxy-6-methyl-2H-pyran-2-one, and arylhydrazine in acetonitrile under reflux condition and in the presence of piperidine is reported. This three-component reaction has some advantages such as ease of handling, good yields, and easy purification. All structures were confirmed by infrared, mass, ¹H NMR, and ¹³C NMR spectroscopy.     

Efficient One-Pot Synthesis of Alkyl 2-(Bromomethyl)-2-(4-aryl)-4-alkoxy-5-oxo-2,5-dihydrofuran-3-carboxylate

One-pot, three-component reaction of different phenacyl bromides and dialkylacetylenedicarboxilates was carried out with triphenylphosphine and functionalized oxodihydrofuran derivatives in excellent yields.     

Silica Gel Catalyzed Conversion of Dialkyl 2-(1-Hydroxy-2-naphthyl)-3-(triphenylphosphoranylidene)butanedioates to Alkyl 2-Oxo-2 H -benzo[ h ]chromene-4-carboxylates in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 1-hydroxynaphthalene leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(1-hydroxy-2-naphthyl)-3-(triphenylphosphanylidene)butanedioates. Silica gel was found to catalyze conversion of dialkyl 2-(1-hydroxy-2-naphthyl)-3-(triphenylphosphanylidene)butanedioates to alkyl 2-oxo-2 H -benzo[ h ]chromene-4-carboxylates in solvent-free conditions at 80°;C in fairly good yields.     

Synthesis and Crystal Structure of 4-Bromo-5-ethoxy-3-methyl-5- （naphthalen- 1-yl）- 1-tosyl- 1H-pyrrol-2（5H）- one

The title compound 4-bromo-5-ethoxy-3-methyl-5-(naphthalen-1-yl)-1-tosyl-1H- pyrrol-2(5H)-one 1 (C24H22BrNO4S, Mr = 500.40) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 8.8562(15), b = 18.118(3), c = 14.055(2) , β = 99.855(3)o, V = 2221.9(6) 3, Z = 4, Dc = 1.496 g/cm3, μ = 1.975 mm-1, λ = 0.71073 , F(000) = 1024, R = 0.0607 and wR = 0.1371.     

Novel,Simple, and Efficient Synthesis of 3-(2-(5-(Benzylideneamino)-3-phenyl-1H-pyrazol-1-yl)thiazol-4-yl)-4-hydroxy-6-methyl-2H-pyran-2-one Derivatives via a One-Pot,Four-Component Condensation Reaction

The synthesis of 3-(2-(5-(benzylideneamino)-3-phenyl-1H-pyrazol-1-yl)thiazol-4-yl)-4-hydroxy-6-methyl-2H-pyran-2-one derivatives was achieved through a one-pot, four-component reaction involving condensation of 3-(2-bromoacetyl)-4-hydroxy-6-methyl-2H-pyran-2-one, thiosemicarbazide, phenacylcyanaide, and various aryl aldehydes in dry alcohol and few drops of acetic acid under reflux condition. This four-component reaction has some advantages such as ease of handling, good yields, and easy workup. All structures of newly prepared compounds were confirmed by analytical and spectral data.     

Synthesis of Dialkyl 4-Ethoxy-2,5-dihydro-1-(9,10-dihydro-9,10-dioxoanthracen-1-yl)-5-oxo-1H-pyrrole2,3-dicarboxylates

Abstract

The reaction of ethyl 9,10-dihydro-9,10-dioxoanthracen-1-yl-carbamoyl-formate with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine leads to dialkyl 4-ethoxy-2,5-dihydro-1-(9,10-dihydro-9,10-dioxoanthracen-1-yl)-5-oxo-1H-pyrrole-2,3-dicarboxylates in fairly good yields. A dynamic NMR effect is observed as a result of restricted rotation around the single bond linking the anthraquinone moiety and the heterocyclic ring system, which is attributed to the interaction between the pyrrole residue and the peri C═O group.     

Synthesis and Dynamic NMR Spectroscopic Study of Dialkyl 4-Ethoxy-1-(1-naphthyl)-5-oxo-4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrrole-2,3-dicarboxylates

Summary. Protonation of the reactive 1:1 intermediate produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates with ethyl 2-(1-naphthylamino)-2-oxoacetate, leads to a vinylphosphonium salt, which undergoes intramolecular Wittig reaction to produce dialkyl 4-ethoxy-1-(1-naphthyl)-5-oxo-4,5-dihydro-1H-pyrrole-2,3-dicarboxylates in excellent yields. A dynamic NMR effect is observed in the ¹H NMR spectra of the title compounds as a result of restricted rotation around the single bond linking the naphthalene moiety and the heterocyclic system, which is attributed to the peri interaction between the pyrrole residue and the peri CH group. The free energy of activation (G ) for this process is 58±2kJmol^–1.Received December 6, 2002; accepted December 11, 2002 Published online June 12, 2003     

Synthesis of 2-(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-carbonyl)-6,6-dimethyl-3-phenyl-3,5,6,7-tetrahydro-2H-benzofuran-4-one Derivatives via Multicomponent Reaction

A sequential one-pot, two-step reaction for an efficient preparation of 2-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-carbonyl)-6,6-dimethyl-3-phenyl-3,5,6,7-tetrahydro-2H-benzofuran-4-one derivatives has been described. One-pot reaction of in situ–formed benzopyran-substituted pyridinium ylides with aromatic aldehydes and dimedone gives corresponding 2,3-dihydrofurans in good yields. The structures of all the newly synthesized compounds were confirmed from their analytical and spectral data.     

Synthesis of Stable Atropisomers of Dialkyl-4-Ethoxy-1-(8-((2-ethoxy-2-oxoacetyl)-amino)-1-naphthyl)-5-oxo-4,5-dihydro-1H-pyrrole-2,3-dicarboxylates

Summary.  Protonation of the reactive 1:1-intermediate produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates with diethyl N,N′-(naphthalene-1,8-diyl)-dioxamate leads to a vinylphosphonium salt which undergoes an intramolecular Wittig reaction to produce dialkyl-4-ethoxy-1-(8-((2-ethoxy-2-oxoacetyl)-amino)-1-naphthyl)-5-oxo-4,5-dihydro-1H-pyrrole-2,3-dicarboxylates in good yields. The title compounds exist as stable rotamers as a result of restricted rotation around the single bond linking the naphthalene moiety and the heterocyclic system. The calculated free energy of activation for interconversion of the atropisomers amounts to about 102±2 kJ · mol⁻¹. Corresponding author. E-mail: isayavar@yahoo.com Received February 5, 2002. Accepted March 19, 2002     

Stereoselective Synthesis of Some Dialkyl (E)-2-Bromomethylene Glutarates

Reaction of 2-bromo-2-bromomethyl glutaric acid esters with tetraalkylammonium fluoride in HMPA, conveniently provides the corresponding dialkyl (E)-2-bromomethylene derivatives in good yields.     

1-甲基-3,4-二苯基喹啉-2(1H)-酮的合成和结构表征

以N-甲基苯胺和苯丙炔酸为原料,经过缩合、亲电环化、偶联反应合成了1-甲基-3,4-二苯基喹啉-2(1H)-酮;利用核磁共振谱和气相色谱-质谱表征了产物的结构.结果表明,所用合成方法具有产率高、反应条件温和、操作简单等优点,目标产物的总产率达62.7%.