Synthesis of a series of pyrrole-1-acetic acids as potential antiinflammatory agents

A series of 3-substituted 2-amino-4,5-dimethylpyrrole-1-acetic acid derivatives were synthesized. The condensation of acetyl methyl carbinol, ethyl glycinate, and the appropriate acetonitrile yielded ethyl 3-substituted 2-amino-4,5-dimethylpyrrole-1-acetate, which was consequently hydrolyzed to produce the corresponding carboxylic acid. The acetamide and trifluoroacetamide series were synthesized by reacting the ethyl 2-aminopyrrole-1-acetates with acetyl chloride or trifluoroacetic anhydride respectively. The corresponding 2-acetamidopyrrole-1-acetic acids were formed by basic hydrolysis of the ethyl esters.     

Reaction of 2-dimethylaminomethylene-1,3-diones with dinucleophiles. VIII. Synthesis of ethyl and methyl 2,4-disubstituted 5-pyrimidinecarboxylates

Reaction of ethyl or methyl 2-dimethylaminomethylene-3-oxoalkanoates with N-C-N dinucleophiles such as guanidine, acetamidine or benzamidine afforded in high yields the relative esters of 4-substituted 2-amino-, 2-methyl- or 2-phenyl-5-pyrimidinecarboxylic acids, respectively. These esters were hydrolyzed to the corresponding carboxylic acids, which were converted by heating to 4-substituted 2-pyrimidinamines, 2-methyl or 2-phenylpyrimidines, respectively, generally in excellent yields. The 4-unsubstituted ethyl 2-amino-, 2-methyl- and 2-phenyl-5-pyrimidinecarboxylates were obtained in moderate yields by reaction of the above dinucleophiles with ethyl 2,2-diformylacetate. These esters were hydrolyzed and the corresponding acids (with the exception of the 2-methyl derivative) were decarboxylated to give 2-pyrimidinamine and 2-phenylpyrimidine in satisfactory yields.     

Synthesis of 1-amino-2-vinylcyclopropane-1-phosphinates. Conversion of a phosphonate to phosphinates

Conversion of diethyl 1-amino-2-vinylcyclopropanephosphonate to ethyl 1-amino-2-vinylcyclopropanephosphinate was accomplished by using either nucleophilic or electrophilic carbon reagents. Hydrolysis of the phosphonate diethyl ester to the mono acid followed by oxalyl chloride treatment provided the phosphonomonochloridate, which was treated with nucleophilic organometallic agents to afford phosphinate ethyl esters. Alternatively, the chloridate was reduced to the phosphonous ethyl ester, and then alkylated with various electrophilic alkylating agents to obtain phosphinate ethyl esters.     

Analogs of D(+)-pantothenic acid. VI. Synthesis of D-, L-, and DL-4′-amino-4′-deoxypantothenic acid

A new analog of pantothenic acid, DL-4-amino-2-hydroxy-3,3-dimethylbutanoic acid, has been synthesized and it has been separated into stereoisomer. D-, L-, and DL-N-(4-Amino-2-hydroxy-3,3-dimethylbutyryl)-β-alanines — amino analogs of pantothenic acid — have been synthesized by the condensation of the N-hydroxysuccinimide esters of N-BOC-D-, -L-, and -DL-4-amino-2-hydroxy-3,3-dimethylbutanoic acids with β-alanine, followed by the elimination of the protective groups.     

Reaction between quinone and thiazolidine. A study on the formation mechanism of new antiproliferative quinolindiones

Reaction between quinolinquinone and thiazolidine in basic medium was investigated. 2-Arylthiazolidine-4-carboxylic acid ethyl esters undergo two different cleavages in basic medium, yielding the 1-aryl-2-azadiene and a thiolic species. In the presence of quinolinquinone, the isomeric 1-aryl-3-ethoxycarbonyl-pyridoisoquinolin-5,10-diones and 3-amino-3-ethoxycarbonyl-dihydrothienoquinolin-4,9-diones are formed by a hetero-Diels-Alder reaction and 1,4-Michael addition reaction, respectively. A mechanism for the formation of the reaction products is presented.     

Die 1,3-dipolare Cycloaddition von Acetylendicarbonsäure-estern an 2-Methyl-4-phenyl-chinazolin-3-oxid

The 1,3-dipolar addition of acetylenedicarboxylic esters (IX and X) to 2-methyl-4-phenyl-quinazoline 3-oxide (VIII) in benzene/methanol and benzene/ethanol, respectively, gives the esters XI and XII of 3-amino-3-phenyl-2-(2-acetamidophenyl)-acrylic acid as main products and the esters XIII and XIV of 2-methyl-4-phenyl-5H-benzo[d][1,3]diazepin-5-carboxylic acid as by-products. The constitutions of XI and XII are elucidated by acid hydrolysis to the 2-phenylindole-3-carboxylic esters VI and VII, respectively, and by ozonolysis of XII to give benzamide and ethyl o-acetamido-mandelate (IV). The alkaline hydrolysis of XI or XII gives the enamine derivative XVIII, which is hydrolysed by acid to oxindole and benzoic acid. The structure elucidation of XIII and XIV is based on spectroscopic data together with thc formation of XV by alkaline hydrolysis. Mechanisms arc proposed for the reaction paths.     

Synthesis of polyheterocyclic compounds derived from 6-amino- 4-aryl-2-r-4h-furo[2,3-<Emphasis Type="Italic">b</Emphasis>]pyran-5-carbonitriles

Syntheses were developed for 4-aryl-6-ethoxy-2-R-furo[2,3-b]pyridine-5-carbonitriles and ethyl esters of 5-amino-4-aryl-7-methyl-2-R-1,9-dioxa-8-azacyclopenta[b]naphthalene-6-carboxylic acids based on the reaction of 6-amino-4-aryl-2-R-4H-furo[2,3-b]pyran-5-carbonitriles with ethyl acetoacetate and nucleophilic recyclization. The mechanisms of these reactions are considered.     

Synthesis of pyridines by heterocyclization of new dienamino esters

The synthesis of pyridine derivatives is reported starting from the new dienamino esters 2 . Thermal cyclization of 2 afforded the ethyl 2-amino-3-pyridinecarboxylate derivatives 3 ; from the reaction of 2 in sodium ethoxide the 2-aminopyridines 3 and 4 , and the 1,2-dihydro-2-oxopyridines 5 and 6 were obtained.     

A new synthesis of dl-5-vinyloxazolidine-2-thione,a natural antithyroid factor

A new procedure for the preparation of DL-5-vinyloxazolidine-2-thione (goitrin) 3 via a facile and practical synthesis of the key intermediate DL-1-amino-3-buten-2-ol 2 is described.     

Synthesis of 6-amino-4-aryl-5-cyano-3-(3-cyanopyridin-2-ylthiomethyl)-2,4-dihydropyrano[2,3-c]pyrazoles and their hydrogenated analogs. Molecular structure of 6-amino-5-cyano-3-(3-cyano-4,6-dimethylpyridin-2-ylthiomethyl)-4-(2-nitrophenyl)-2,4-dihydropyrano[2,3-c]pyrazole

Substituted 3-hydroxypyrazoles, which were prepared based on ethyl esters of substituted 4-(pyridin-2-ylthio)- or 4-(1,4-dihydropyridin-2-ylthio)acetoacetic acids and hydrazine hydrate, were used in the synthesis of 6-amino-4-aryl-5-cyano-3-(pyridin-2-ylthiomethyl)-2,4-dihydropyrano[2,3-c]pyrazoles. The molecular and crystal structure of 6-amino-5-cyano-3-(3-cyano-4,6-dimethylpyridin-2-ylthiomethyl)-4-(2-nitrophenyl)-2,4-dihydropyrano[2,3-c]pyrazole was established by X-ray diffraction analysis.     

Interaction of esters of β-aroylacrylic acids with <Emphasis Type="Italic">o</Emphasis>-phenylenediamines and 1,2-diamino-4-phenylimidazole

3-Phenacylquinoxalin-2-ones were synthesized by the reaction of the ethyl esters of β-aroylacrylic acids with o-phenylenediamines, while interaction with 1,2-diamino-4-phenylimidazole gave ethyl 7-amino-2-aryl-5-phenyl-3,4-dihydroimidazolo[1,5-b]pyridazine-4-carboxylates. Their chemical properties have been investigated. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1646–1654, November, 2007.     

Synthesis of 2-amino-5-(2-aryl-2-oxoethylidene)-4-oxo-1<Emphasis Type="Italic">H</Emphasis>-4,5-dihydrofuran-3-carboxylic acids derivatives by recyclization of 5-arylfuran-2,3-diones under the action of cyanoacetic acid derivatives

Recyclization of 5-arylfuran-2,3-diones under the action of ethyl cyanoacetate or of malonic acid dinitrile resulting in the corresponding esters or nitriles of 2-amino-5-(2-aryl-2-oxoethylidene)-4-oxo-1Н-4,5-dihydrofuran-3-carboxylic acids was investigated.     

Ring expansion reactions of 4-amino-1,1-dioxo-[1,2,3,5]-thiatriazoles

An unusual ring-expansion reaction of 4-amino-1,1-dioxo-[1,2,3,5]-thiatriazoles has been identified that produces the relatively rare 5-amino-1,1-dioxo-[1,2,4,6]-thiatriazines and. Initial alkylation of the thiatriazole with alpha-halo-esters at N-3 produces alpha-substituted esters which, under basic reaction conditions, undergo opening of the thiatriazole ring and re-closure to a thiatriazine ring. Similar alkylations of with diethyl chloromalonate and ethyl dichloroacetate lead to the loss of SO2 and the production of triazine and triazole, apparently by an initial alkylation at N-5. The reaction of with phenacyl bromides or a phenacyl dibromide forms fully unsaturated 5-amino-1,1-dioxo-[1,2,4,6]-thiatriazines.     

Facile Synthesis of Nicotinic Acid Derivatives with Unsymmetrical Substitution Patterns

Abstract

Two novel methods for synthesis of nicotinic acid derivatives with unsymmetrical substitution patterns were presented via ketene dithioacetals. The ketene N,S-acetals 2 reacted with β-ketoesters or β-cyanoesters to give 4-amino-5-cyano-2-alkyl-6-methylthio-nicotinic acid derivatives 3 or 2,4-diamino-5-cyano-6-methylthio-nicotinic acid ethyl ester 4. However, 6-amino-5-cyano-2-alkyl-4-methylthio-nicotinic acid esters 6 were obtained by the reaction of the ketene dithioacetals 1 and β-amino-crotonates.     

Facile synthesis of 5-amino- and 7-amino-6-azaoxindole derivatives

An efficient approach for the formation of 5-amino- and 7-amino-6-azaoxindole derivatives was developed. 2-Amino-4-chloro-3-nitropyridine (8), and its 5-nitro-substituted regioisomer (9), respectively, were obtained by reaction with ethyl malonate. The resulting 2-amino-3/5-nitropyridine derivatives substituted in the 4-position with malonic acid diethyl ester (10, 11) were subjected to reductive cyclization yielding 3-ethoxycarbonyl-6-azaoxindole derivatives 4a and 5a. Protection of the amino function was not required. Intermediates 10 and 11 could also be converted to the corresponding 4-acetic acid ethyl esters 12 and 13 by dealkoxycarbonylation with LiCl, and subsequently cyclized under reductive conditions yielding 3-unsubstituted 5-/7-aminooxazindoles.     

Thiazolecarboxylic Acid Derivatives. 1. N-Substituted 2-Amino-4-methylthiazole-5-carboxylic Acid Derivatives

Acylation of the ethyl ester and anilide of 2-amino-4-methylthiazole-5-carboxylic acid gave 2-acetyl(arylsulfonyl)amino derivatives. Methylation of acetylaminothiazole and subsequent deacetylation gave 2-methylamino-4-methylthiazole-5-carboxylic acid, which was then converted into esters. The ethyl ester and anilide of thiazole-2-carboxylic acid were used as starting compounds for the synthesis of 2-dimethylaminoformimino- and 2-chlorobenzenesulfonylureido derivatives.     

6-氨基-2-取代吲哚-3-羧酸乙酯及其衍生物的合成与生物活性评价

以2,4-二硝基氯苯和乙酰乙酸乙酯为原料, 经过亲核置换、还原-环化协同反应, 合成了6-氨基-2-甲基吲哚-3-羧酸乙酯, 而后在催化剂作用下, 与乙酰乙酸乙酯反应生成烯胺, 环化合成9-羟基-2,7-二甲基吡咯(2,3-f)喹啉-3-羧酸乙酯; 类似地, 合成了6-氨基-2-苯基吲哚-3-羧酸乙酯和6-氨基-2-(呋喃-2'-基)吲哚-3-羧酸乙酯. 其结构均由¹H NMR, IR以及MS波谱数据表征. 所得化合物具有抑制肺癌A549细胞生长的活性, 其抑制效果具有浓度依赖性.     

A new method for the synthesis of esters of β-thiophenecarboxylic acids

A method for the synthesis of esters of -thiophenecarboxylic acids and diethyl 3-methyl-2,4-thiophenedicarboxylate by the deamination of derivatives of 2-amino-3-ethoxycarbonylthiophene has been proposed. Ethyl tetrahydrothionaphthene-3-carboxylate has been converted by dehydrogenation on heating with sulfur into ethyl thionaphthene-3-carboxylic acid. The corresponding acids have been obtained by the hydrolysis of the esters. A number of dialkylaminoalkyl esters has been obtained from -thiophenecarboxylic acids and 3-methyl-2, 4-thiophenedicarboxylic acid via the acid chlorides.     

Cyanide ion promoted addition of acyl phosphonates to ethyl cyanoformate: synthesis of tertiary carbinols via tandem carbon-carbon bond formations

New cyanation/phosphonate-phosphate rearrangement/C-acylation reactions of cyanophosphate anion with cyanoformate esters are described. Phase-transfer cocatalysts facilitate cyanide-catalyzed reactions between acyl phosphonates and cyanoformates to afford protected tertiary carbinol products in good to excellent yields (74-95%). Ethyl cyanoformate is used as a cyanide source and electrophile. The scope of the reaction was investigated by using a number of benzoyl and acyl phosphonates along with ethyl cyanoformate. Representative chemoselective reduction of the product 5a afforded ethyl 3-amino-2-hydroxy-2-phenylpropanoate (13) in good yield.     

Synthesis and properties of some 7-dimethylamino-1,4-benzoxazin-2-ones

The synthesis of the 7-dimethylamino-1,4-benzoxazin-2-ones ( 5 ), fluorescent dyes, by condensing α-keto-acids with 2-amino-5-dimethylaminophenol is described. When the 3-substituent is a methyl group, these compounds can be further condensed with aromatic aldehydes to provide the styryl dyes ( 6 ). These products are easily opened by hydrochloric acid in ethanolic solution to afford the corresponding benzalketoacid ethyl esters ( 7 ).