Oxa-Pictet-Spengler reaction in water.Synthesis of some(±)-1-aryl-6,7-dimethoxyisochromans

An acid catalyzed oxa-Pictet-Spengler reaction‘on water leading to the synthesis of a variety of l-aryl-6,7-dimethoxyisochro-mans is described.The aqueous chemistry is a much cleaner,efficient,cheaper and simple method for synthesis.The scope of reactions was extended to thia-Pictet-Spengler reaction to afford the some isothiochromans.

3-(2′-苯基-1′,2′,3′-连三唑-4′-基)-6-烷基/芳基-均三唑并[3,4-b]-1,3,4-噻二唑的合成

研究了3-(2′-苯基-1′,2′,3′-连三唑-4′-基)-4-氨基-5-巯基-1,2,4-三唑(1)与取代苯甲酸和脂肪酸(2a～r)在POCl_3催化下的反应,共合成得到18个新的3-(2′-苯基-1′,2′,3′-连三唑-4′-基)-6-烷基/芳基-均三唑并[3,4-b]-1,3,4-噻二唑(3a～r),经元素分析,IR,~1H NMR和MS进行了结构确证.

Synthesis of Some Hexahydroquinazolinones Using K₃AlF₆(Al₂O₃/KF) as an Efficient Catalyst in Some Hexahydroquinazolinone Derivatives

A protocol for the synthesis of some 4-Aryl-1,3,4,6,7,8-hexahydroquinazolin-2,5(1H,6H)-diones (HHQs) was developed by means of a three-component condensation reaction of an aromatic aldehyde, 1,3-cylohexadione and urea in the presence of K3AlF6 (Al2O3/KF) as catalyst. This reaction is carried out under different conditions including 1) solvent free;2) reflux in acetonitrile;3) reflux in ethanol;4) reflux in chloroform;and 5) reflux in water. In all conditions, the desired products are obtained in high yields after relatively short reaction times. Nevertheless, the reactions proceed faster and in higher yields when they were carried out in acetonitrile. This adopted protocol for some Biginelli-type products has offered the advantages of reusability of the catalyst, high yields and ease of separation of pure products. Furthermore, the catalyst is easily prepared, stabilized and efficiently used under reaction conditions.

Improved microwave-assisted catalyst-free synthesis of9-aryl-5,9-dihydropyrimido[4,5-d][1,2,4]triazolo[1,5-a]pyrimidine-6,8(4H,7H)-dione derivatives

Agreen regioselective synthesis of some new and known 9-aryl-5,9-dihydropyrimido[4,5-d][l,2,4]triazolo[1,5-a]pyrimidine-6,8（4H,7H）-diones has been described via the microwave-assisted one-pot reaction of 3-amino-1H-1,2,4-triazoles,aromatic aldehydes and barbituric acids under solvent- and catalyst-free conditions.This operationally simple procedure is less laborious and provides a better scope than previously reported procedures.

A new phenolic compound from Crinum asiaticum L.

A new phenolic compound was isolated from the ethanol extract of the bulbs of Crinum asiaticum L.var.sinicum Baker.Its structure was defined as 1-（2-hydroxy-4-hydroxymethyl）phenyl-6-O-caffeoyl-β-D-gluco-pyranoside on the basis of spectroscopic evidences.

An environmentally friendly synthesis of 1,4-dihydropyrano[2,3-c]pyrazole derivatives catalyzed by tungstate sulfuric acid

An efficient three-component synthesis of 6-amino-4-aryl-5-cyano-3-metriyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles via a reaction between 3-methyl-1-phenyl-2-pyrazolin-5-one,aromatic aldehydes and malononitrile using tungstate sulfuric acid as a catalyst was described.Mild conditions,good to excellent yields,easily available catalyst and easy work-up are the key features of this method.