Synthesis of 4-Aminosalicylglycine

To search for a better prodrug of 4-aminosalicylic acid that is expected to deliver stably parent drug to colon against the inflammatory bowel disease, a novel 4-aminosalicylic acid derivative was designed and synthesized from 4-aminosalicylic acid. 4-Aminosalicylglycine was prepared from 4-aminosalicylic acid by protecting amino and hydroxyl groups with benzyloxycarbonyl and acetyl, respectively, then the carboxylic acid was converted to acyl chloride which was treated with glycine. After removing the protection groups, 4-aminosalicylglycine wasobtained. All the compounds were characterized by FT-IR, ^1H-NMR, ^13C-NMR spectra. In vivo experiment on rats suggested that the curative effect of 4-aminosalicylglycine was more effective than that of 4-aminosalicylic acid.     

New Approach to Synthesis of 6,7—Dimethoxyisatin

A new approach to synthesis of 6,7-dimethoxyisatin is reported.2-nitro-3,4-dimethoxy mandelonitrile in glacial acetic acid was treated with the solution of stannous chloride in hydrochloric acid to give 6,7-dimethoxyisatin in a high yield.     

SYNTHESIS OF AN EPOXY-TERMINATED HYPERBRANCHED AROMATIC POLYESTER

An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromaticpolyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of the AB_2monomer, 5-acetoxyisophthalic acid. Polymer P1 was converted into the polymeric acid chloride by reaction with thionylchloride. The acid chloride was reacted with ethanol and glycidol to form a poly(ethyl ester) (P2) and an epoxy terminatedmaterial (P3), respectively. The reaction conditions in each step of these processes had to be controlled very carefully toavoid unwanted cross-linking reactions. The characterization of products and intermediates, including molecular weightdistributions and thermal properties, are reported.     

Novel Synthesis of N-Substituted p-Hydroxybenzoic Amides on Soluble Polymer-Support

The synthesis of N-substituted p-hydroxybenzoic amides using a liquid phase approach is described. Poly(ethylene glycol)(PEG) and p-hydroxybenzoic acid were linked by oxalyl chloride to give compound 1, which was chlorinated by thionyl chloride, followed by amidation with NHR^1R^2 to yield compound 3. Hydrolysis of compound 3 gave the title amide 4.These crude library members were obtained in good yields with high purities.     

A "one-pot" synthesis of α-(p-toluenesulfonyl)-aminobenzylphosphinodipeptide derivatives containing a P-N bond

With acetyl chloride as the solvent, the condensation reaction of p-toluenesulfonamide, an aromatic aldehyde and phenyldichlorophosphine gives a reactive intermediate, a-(p-toluenesulfonyl)-aminobenzylphosphinic chloride, which reacts with glycine ethyl ester to give the corresponding phos-phinopeptide (6) containing a P-N bond directly.     

Advances in self-assembly and regulation of aromatic carboxylic acid derivatives at HOPG interface

Aromatic carboxylic acid self-assembly has been a hot research field for many scientists due to its strong coordination ability and flexible coordination mode.The hydrogen bond formed between aromatic carboxylic acids is a strong intermolecular force and has directionality and saturation,which plays a very important role in the self-assembly and regulation of aromatic carboxylic acids.In this review,we introduce surface organization formed by aromatic carboxylic acids with the aid of scanning tunneling microscopy(STM).These two-dimensional structures include molecular templates,host-guest systems,and photo-isomerization structures.We also emphasize the thermodynamics and dynamics,which are important research topics of current and future study.     

A Selective Synthesis of 2-Alkylamino-5, 6, 7, 8-tetrahydrobenzothieno[2, 3-d]pyrimidin-4（3H）-ones

2-Alkylamino-5, 6, 7, 8-tetrahydrobenzothieno [2,3-d] pyrimidin-4(3H)-ones 7 were synthesized by a new selective synthetic method, which includes aza-Wittig reaction of iminophosphorane 4 with aromatic isocynate to give carbodiimide 5 and subsequent reaction of 5 with various aliphatic primary amine in the presence of EtO^-Na^ .     

Poly（ethylene glycol）-supported Liquid-phase Parallel Synthesis of Di（aryloxyacetyl）thiosemicarbazides

An efficient poly(ethylene glycol) (PEG)-supported liquid-phase parallel approach to di(aryloxyacetyl)thiosemicarbazides is described. PEG-bound phenol reacted with chloroacetic acid to afford PEG-bound phenyloxyacetic acid, which was readily converted into corresponding phenyloxyacetyl chloride. Subsequent nucleophilic substitution with ammonium thiocyanate followed by addition of aryloxyacetic acid hydrazides gave PEG-bound di(aryloxyacetyl)thiosemicarbazides, which were easily cleaved to give the resulting library of 1-aryloxyacetyl-4-(4‘-methoxylcarbonylphenyloxyacetyl)thiosemicarbazides in good to high yield and high purity.     

A New Solution—phase Parallel Synthesis of 2—Alkyamino—3—aryl—5—phenylmethylene—3,5—dihydro—4H—imidazol—4—ones

Thirteen new 2-alkylaminoimidazolones(4) wre rapidly synthesized by a new solution-phase parallel synthetic method,which includes aza-Wittig reaction of iminophosphorane(1) with aromatic isocyanate to give carbodi-imide(2) and subsequent reaction of 2 with various aliphatic primary amine in a parallel fashion.The products were confirmed by ^1H NMR,MS,IR and X-ray crystallographic analysis.The unusual selectivity of the cyclization was probably due to the deometry of the guanidine intermediate.     

Separation of Aromatic Carboxylic Acids in IC and the Study on the Relationship Between Retention Behavior and Electrostatic Potential

A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column (250mm×2mm) was used with a 9mmol/L sodium carbonate solution containing 50% (v/v) acetonitrile as eluent. A set of retention time data has been obtained using a conductivity detector DS6. Furthermore, geometrical optimization and electrostatic potential calculation of 20 kinds of aromatic carboxylic acid have been performed at the HF/6-31G* level of theory. A number of statistically-based parameters derived from molecular surface electrostatic potential have been obtained. Linear relationship between retention time and structural parameters has been established by multiple regression method. The result shows that parameters derived from electrostatic potential Vs +, Vs -, П together with the dipole moment μ can be well used to express the quantitative structure-retention time of this kind of aromatic carboxylic acid. Good predictive capability has also been demonstrated. The result has provided a framework which further proves the general applicability of this electrostatic potential parameter set to a great extent,and with which the ion chromatographic adsorption mechanism can be investigated.     

A Rapid Parallel Synthesis of 2-Dialkylamino-4（3H）-quinazolinones

2-Dialkylamino-4(3H)-quinazolinones 4 were rapidly synthesized by a solution-phase parallel synthetic method, which includes aza-Wittig reaction of iminophosphorane 1 with aromatic isocynate to give carbodiimide 2 and subsequent reaction of 2 with various aliphatic secondary amine in a parallel fashion.     

Synthesis of 5-Fluoroalkyl Isoxazolidines via 1,3-Dipolar Cycloaddition of Ethyl 2-Hydropolyfluoroalk-2-enoates with Nitrones

1,3-Dipolar cycloaddition reactions of ethyl 2-hydropolyfluoroalk-2-enoates (1) with some nitrones were described. The reaction of 3,4-dihydroisoquinoline N-oxide (2) with 1 took place readily in methylene chloride at room temperature to give the corresponding 5-fluoroalkylisoxazolidines regioselectively as a mixture of two diastereoisomers (trans and cis) in high yields, while longer reaction time and higher temperature were needed in the case of non-cyclic nitrones. Under similar conditions the reaction of quinoline N-oxide (14) with 1 did not give the expected adducts and a ring-opening product was obtained.     

Novel Synthesis of Barbiturates

Knovenagel reaction of barbituric acid with different aldehydes were used to synthesize new barbiturates. This is a novel method which can be used to synthsis various types of new generation of barbiturates which are different from the previously reported.     

无溶剂条件下锰 (Ⅲ)-席夫碱配合物催化过氧化氢氧化醇

 Aliphatic and aromatic alcohols are efficiently oxidized to ketones or carboxylic acids using aqueous hydrogen peroxide as an oxidant in the presence of a Mn(III) Schiff-base complex as a catalyst under solvent-free conditions. The oxidation of alcohols occurred at 50 °C to give the corresponding ketones or carboxylic acids with a yield higher than 60%.     

Synthesis of azo derivatives of 4-aminosalicylic acid

For searching a better 4-aminosalicylic acid derivative with higher activity and less side effects against the inflammatory bowel disease, 4-aminosalicylic acid (4-ASA) was protected by benzyloxycarbonyl and acetyl, respectively. The resultant was hydrogenized to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, TV-salicyloyl glycine acid to get azo derivatives of 4-ASA. The azo derivatives were hydrolyzed under the alkaline condition to get the target products. All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectra in details. New derivatives of 4-ASA were characterized. The synthetic route was reasonable and feasible.     

An efficient chlorination of aromatic compounds using a catalytic amount of iodobenzene

An efficient method was developed for chlorination of aromatic compounds with electron-donating groups using iodobenzene as the catalyst and m-chloroperbenzoic acid as the terminal oxidant in the presence of 4-methylbenzenesulfonic acid in THF at room temperature for 24 h,and a series of the monochlorinated compounds was obtained in good yields.In this protocol,the catalyst iodobenzene was first oxidized into the hypervalent iodine intermediate,which then treated with lithium chloride and finally reacted with aromatic compounds to form the chlorinated compounds.     

Esterification and Selective Esterification in the Presence of TiCl4

A series of carboxylic acids was esterified to the corresponding esters with TiCl_4 as catalyst at room temperature,in high yields.This catalyst was highly effective for the selective esterification of primary alcohols with carboxylic acids,in the presence of secondary alcohols,and for the selective esterification of saturated acid with alcohol in the presence of conjugated acid or aromatic acid.On account of the high yield,high chemoselectivity,mild condition,and being free of other dehydrants,this is an efficient method.     

Synthesis, Crystal Structure and Electrochemical Properties of the Complex Cd（α-FRA）2（Phen）（H2O）

1 INTRODUCTION The syntheses and structures of carboxyl complex- es have captured the interest of chemists for years due to their potential applications in many fields, such as materials, medicine, molecular electro-che- mistry and biochemistry[1～3]. So far, to the best of our knowledge, cadmium complexes with aromatic carboxylic acid as ligands have been intensively studied[4～7], but those with heterocyclic carboxylic acid as ligands are much less. α-Furoic acid is widely used in orga…     

Syntheses of 10-Hydroxy-5,10-dihydrophenophosphazine 10-Oxide and Its Methyl Derivatives

Ph2NH and PCl3 interacted at a molar ratio of 1:1.05 and slow-elevated temperature and then at 210-220 ℃ for 6h.The brown solution obtained was treated with H2O to produce a very hard brown solid believed to be a mixture of 5,10-dihydrophenophosphazine 10-oxide(1a) and 10,10′(5H,5H′）-spirobipenophosphazinium chloride(1b).This brown solid was directly oxidized with peracetic acid in HOAc prior to the separation of them to give compound 10-hydroxy-5,10-dihydropheno-phosphazine 10-oxide(2) with a higher yield(45%) than that of the literature(27%).When treated with excess SOCl2.compound 2 could quantitatively be converted to the corresponding phosphinyl chloride and the latter could further be transformed into 10-methoxy-5,10-dihydrophenophosphazine 10-oxide in 70% as treated with NaOMe in methanol.Compound 2 could also be converted to a bisanion when treated with NaH in DMF.The resulted bisanion reacted with MeI to give 5-methyl-10-hydroxy-5,10-dihydrophenophosphzine 10-oxide in a 73% yield which would be converted to 5-methyl-10-methoxy-5,10-dihydrophenophosphazine 10-oxide.All these compounds obtained were identified by surveying their melting points.and spectra and elemental analysis.     

Solid Phase Synthesis of β-Carbolines

Much attention has been paid to carbolines in recent years, owing to the wide range of their biological activity 1. Many papers have reported the synthesis and reactivity of carbolines2,3. Generally there are two ways to synthesize carbolines. One is through the Bischler-Napieralski reaction, and the other through Pictet-Spengler reaction. In the former method, the reaction of carboxylic acids with tryptophan using PPE or POCl3 as the condensing agent give dihydro-?-carbolines, which are c…