Weiguo Cao

THE KNOEVENAGEL CONDENSATION OF AROMATIC ALDEHYDES WITH MALONONITRILE OR ETHYL CYANOACETATE IN THE PRESENCE OF CTMAB IN WATER

A new route of Knoevenagel condensation of aldehydes with malononitrile or ethyl cyanoacetate in the presence of CTMAB in water is described. CTMAB is the most effective catalyst to increase yield among CTMAB, BTEAC and TBAI.

KNOEVENAGEL CONDENSATION OF ALDEHYDES WITH CYCLIC ACTIVE METHYLENE COMPOUNDS IN WATER

ABSTRACT A new route of Knoevenagel condensation of aromatic aldehydes with Meldrums acid, barbituric acid and dimedone in the presence of cetyltrimethyl ammonium bromide at room temperature in water is described.

STEREOSELECTIVE SYNTHESIS OF TRANS-β-METHOXYCARBONYL-γ-ARYL-γ-BUTYROLACTONES

ABSTRACT Stereoselective synthesis of trans-β-methoxycarbonyl-γ-aryl-γ-butyrolactones (5) by the reaction of methoxycarbonylmethyl triphenyl arsonium bromide (1) and 2,2-dimethyl-5-substituted-benzal-1,3-dioxa-4,6-dioxa-4,6-dione (2) is carried out in the presence of potassium carbonate and trace water in dimethoxyethane. 1,2-Cis-cyclopropane 3 is formed as an intermediate. The stability of compound 3 in water is related to the property of the aryl substituent. With strong electron-donating groups [2a–c, Ar=4-CH3O‒C6H4; 3,4-OCH2O‒C6H3 or 4-(CH3)2N‒C6H4] at room temperature 3 is formed in situ and transformed to γ-butyrolactones 5a–c immediately, whereas when the aryl substituent is H or a weak electron-donating or electron-withdrawing group (2d–g, Ar=4‒CH3-C6H4; C6H5; 4-Cl‒C6H4 or 4-NO2‒C6H4), 3 is stable to water at room temperature. On further heating in acetone, 3 is transformed to γ-butyrolactones 5d–g (stepwise synthesis). One-pot synthesis of 5d–g from the reaction of 1 with 2d–g is also studied.

THE STEREOSELECTIVE SYNTHESIS OF N-ARYL-TRANS, TRANS-α-CARBOXYL-β-METHOXYCARBONYL-γ-ARYL-γ-BUTYROLACTAMS

Cis-1-methoxycarbonyl-2-aryl-6,6-dimethyl-5,7-diox-spiro-[2,5]-4,8-octadiones (1) in dimethyl ethylene glycol at room temperature react with anilines (2) to give N-aryl-trans,trans-α-carboxyl-β-methoxycarbonyl-γ-aryl-γ-butyrolactams (3) in good to excellent yields and high stereoselectivity.

A green efficient synthesis of spiro[indoline-3,4′(1 H ′)-pyrano [2,3- c ]pyrazol]-2-one derivatives

A highly efficient and green method has been described for the synthesis of spiropyranopyrazole-oxindole in water. The reaction was carried out at ambient temperature and the products were obtained in excellent isolated yields. The structure of the product (4e) was confirmed by X-ray diffraction analysis.

An Efficient and Highly Stereoselective Synthesis of β,γ-Trans-β-Benzoyl-γ-Aryl-γ-Butyrolactones

Abstract Benzoylmethyltriphenylarsonium bromide 6 in the presence of potassium carbonate reacted with 2,2-dialkyl-1,3-dioxa-5-substituted-benzylidene-4,6-dione 2 at room temperature to give β,γ-trans-β-benzoyl-γ-aryl-γ-butyrolactones 7 in good yield.

The Reaction of Electron-Deficient Cyclopropane Derivatives with Aromatic Amines

Abstract N-Aryl-trans,trans-α-carboxyl-β-benzoyl-γ-aryl-γ-butyrolactams were synthesized in high yields with high stereoselectivity by the reaction of electron-deficient cyclopropane derivatives, cis-1-benzoyl-2-aryl-6,6-dimethyl-5,7-dioxo-spiro-[2 5]-4,8-octadiones, with aromatic amines. The reaction mechanism was proposed.

Synthesis of a series of perfluoroalkyl containing spiro cyclic barbituric acid derivatives

An efficient and versatile method for the preparation of a series of perfluoroalkyl containing spiro cyclic barbituric acid derivatives is described. 7,9-Dimethyl-2-(iodomethyl)-3-(perfluoroalkylmethyl) 7,9-diazaspiro[4.5]decane-6,8,10-trione were prepared in good yields from 1,3-dimethylbarbituric acid. The structures of these compounds were confirmed by 1H NMR, 13C NMR, IR, MS spectra and elemental analysis.