A Facile Preparation of Methoxymethyl Ethers of Primary and Secondary Alcohols with Dimethoxymethane Catalysed by Expansive Graphite

An easy preparation of methoxymethyl ethers of primary and secondary alcohols with dimethoxymethane has been carried out in excellent yield under catalysis of expansive graphite.     

Montmorillonite Clay Catalysis. Part 31: A New Ready and High Yield Procedure for the Cleavage of Acetals Catalysed by Montmorillonite K 10

An easy cleavage of acetals has been carried out in excellent yield under catalysis of montmorillonite K 10 in refluxing wet acetone.     

Studies on the synthesis of biomarkers: V. Synthesis of γ-lupane and its epimer

γ-Lupane ( 2 ) and iso-γ lupane ( 10 ) (3α-isopropyl, 5αH) were synthesized from lupeol. The reaction conditions of conversion of lupeol into lupenes and γ-lupenes and the results of catalytic hydrogenation of lupenes and γ-lupenes under different conditions were studied.     

Sulfamic Acid Catalysed Acetylation of Alcohols and Phenols with Acetic Anhydride

An easy acetylation of alcohols and phenols with acetic anhydride has been carried out in excellent yield under catalysis of sulfamic acid.     

超声波在金属参与的有机合成方面的应用

综述了近十几年来超声波在金属参与的有机合成中的一些应用，参考文献44 篇。     

Unexpected Products from the Reaction of Naphthols with Cholesterol Catalysed by Montmorillonite K 10

Under catalysis of montmorillonites, arenes could be cholesterylated by cholesterol (1) via a Friedel-Crafts alkylation.¹ When phenols were employed as substrates for that reaction, aryl cholesteryl ethers were obtained instead of aryl cholestenes.² However, β-naphthol (2a) and α-naphthol (2b) gave obviously different products. We report here the identification of these unexpected products from the reaction of 2 with 1 catalysed by montmorillonite K 10.     

Novel Enone-benzene Rearrangement of 4,4-Dialkylcholest-5-en-3-ones to Ring-B Aromatic Steroidal Hydrocarbons Catalysed by p-Toluenesulfonic acid

Under acidic conditions, α,α-dimethyl-β,γ-unsaturated cyclohexanones undergoes an enone-benzene rearrangement leading to aromatic derivatives^1-4. We recently run an enone-benzene rearrangement of 4,4-dimethyl-cholest-5-en-3-one (1a) catalysed by montmorillonite K-10 to give 1,3,4-trimethyl-19-norcholesta-1,3,5(10)-triene (2a) in moderate yield accompanying intractable mixture of hydrocarbons as by products⁵. Repetition of this reaction by employing TsOH as a catalyst, 2a was obtained in 65% yield and a new product, 6-methyl-3-isopropyl-A,19-dinorcholesta-6,8,10(5)-triene (3a), was also isolated in 25% yield. The formation of 3a has not been reported in earlier studies^1-5. Herein we report the novel enone-benzene rearrangement of 4,4-dialkylcholest-5-en-3-ones (1a~d) leading to ring-B aromatic steroidal hydrocarbons (3a~d) catalysed by TsOH (Scheme 1).     

Synthesis of ethyl alpha-cyanocinnamates catalyzed by KF-Al2O3 under ultrasound irradiation

Knoevenagel condensation of ethyl cyanoacetate with aromatic aldehyde catalyzed by KF-Al2O3 in ethanol results ethyl alpha-cyanocinnamates in 97-99% yield under ultrasound irradiation.     

Ultrasound-assisted synthesis of 1,8-dioxo-octahydroxanthene derivatives catalyzed by p-dodecylbenzenesulfonic acid in aqueous media

An efficient and convenient approach to the synthesis of 3,3,6,6-tetramethyl-9-aryl-1,8-dioxo-octahydroxanthene derivatives using p-dodecylbenzenesulfonic acid (DBSA) as the catalyst (10 mol.%) under ultrasound irradiation is described. This method provides several advantages such as environment friendliness, high yields and simple work-up procedure. In addition, water was chosen as a green solvent.     

An efficient synthesis of 3,4-dihydropyrimidin-2-ones catalyzed by NH2SO3H under ultrasound irradiation

The condensation of aldehydes, beta-keto esters and urea catalyzed by NH(2)SO(3)H in ethanol results dihydropyrimidinones in high yields under ultrasound irradiation.