4-Hydroxy-2-quinolones. 97. Simple synthesis of the esters of 4-halo-substituted 2-oxo-1,2-dihydroquinoline-3-carboxylic acids

Short term treatment of 3-ethoxycarbonyl-4-morpholino-2-oxo-1,2-dihydroquinoline with aqueous solutions of hydrohalogen acids leads to the formation of the ethyl esters of 4-halo-substituted 2-oxo-1,2-dihydroquinoline-3-carboxylic acids. Hydrolysis in HF is possible on extended boiling only to the 4-hydroxy derivative. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1022–1025, July, 2006.     

Unnatural Amino Acids. 2. Simple Method of Obtaining Esters of Aziridine-2-carboxylic Acids by a Transesterification Reaction

A series of N-unsubstituted esters of aziridine-2-carboxylic acid has been obtained by transesterification in basic medium using primary, secondary, and tertiary alcohols. Methods of transesterification using various bases (K₂CO₃, ROLi, t-BuOK) have been compared. Transesterification with lithium alcoholates also affords the possibility of obtaining esters of N-substituted aziridine-2-carboxylic acids. Transesterification of chiral esters proceeds with retention of the configuration of the chiral center.     

Azides of N-substituted aziridine-2-carboxylic acids. Reaction with methyl esters of amino acids

The corresponding azide was obtained by nitrosation of 1-benzylaziridine-2-carboxylic acid hydrazide. Reaction of the azide with methyl esters of amino acids gave N-(1-benzyl-2-aziridinylcarbonyl)-substituted methyl esters of amino acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1350–1352, October, 1980.     

Uncatalyzed solventless Diels-Alder reaction of 2-amino-3-nitroacrylate: synthesis of new epimeric 2-amino-3-nitro-norbornene- and norbornane-2-carboxylic acids

A highly diastereoselective Diels-Alder reaction between cyclopentadiene and ethyl (Z)-2-N-Boc-amino-3-nitroacrylate in neat conditions affords the ethyl 2-t-butoxycarbonylamino-3-endo-nitro-bicyclo[2.2.1]hept-5-ene-2-exo-carboxylate: a new constrained carbocyclic amino acid. Catalytic hydrogenation of this cycloadduct gave the corresponding reduced norbornane derivative. A preliminary investigation into the chemistry of these two amino acids was performed. In particular, the epimerization to their corresponding 3-exo-nitro compounds by treatment both with acid and base was studied. From this study, valuable information on the endo/exo process at the C-3 carbon atom, as well as on the stability of the different stereomers, was obtained. The stability is closely related to the presence or the absence of the double bond in the ring and to the substitution pattern. Finally, deprotection of the amino acid function has been performed.     

Synthesis of 8-substituted bicyclo[3.2.1]octane-6-carboxylic acids and anti-convulsant properties of the corresponding amides

Novel 8-substituted bicyclo[3.2.1]octane-6-carboxylic acids have been made via [3+2]cycloaddition to alkyne 2. A number of the corresponding amides are anti-convulsant in mice.     

Synthesis of derivatives of 2-hydroxyimino- and 2-alkoxyimino-3-(acylhydrazono)butanoic acids

Esters andN-methylamides of 2-hydroxyimino- and 2-alkoxyimino-3-(acylhydrazono)-butanoic acids were synthesized by condensation of acyl hydrazines with the corresponding alkyl 2-hydroxyimino- and 2-alkoxyimino-3-oxobutanoates andN-methyl-2-methoxyimino-3-oxobutanamide. The compounds obtained are analogs of strobilurins, fungicidal antibiotics. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 499–504, March, 1999.     

脱氢丙氨酸酯、酰胺的合成方法研究

本文从Boc保护的丝氨酸出发，经两种途径合成了脱氢丙氨酸酯及其酰胺衍生物，两种合成方法操作简便、产率高、反应条件温和。     

Thioethynyl esters of phosphorus acids

The results of searching for the methods of synthesis of substituted thioethynyl monothio- and dithiophosphates, which are of interest as physiologically active compounds, are summarized. The preparative method for the synthesis of thioesters of O,O-dialkylmonothiophosphoric acids of a specific type was developed: the reaction of substituted ethynyl bromides with potassium salts of the corresponding monothiophosphoric acids in the presence of an equimolar amount of CuCl. These reactions occur through the stage of formation of Cu^I salts of the corresponding monothiophosphoric acids and are accompanied by redox processes leading to the formation of free radicals. The modified method for the synthesis of substituted thioethynyl monothio- and dithiophosphates is the reaction of Cu^I salts of these acids with the corresponding ethynyl bromides.     

4-hydroxy-2-quinolones. 94. Improved synthesis and structure of 1-hydroxy-3-oxo-5,6-dihydro-3h-pyrrolo[3,2,1-i,j]-quinoline-2-carboxylic acid ethyl ester

A modified method is proposed for preparation and purification, and the special features of the spatial structure have been studied for the ethyl ester of 1-hydroxy-3-oxo-5,6-dihydro-3H-pyrrolo[3,2,1-i,j]-quinoline-2-carboxylic acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 718–723, May, 2006.     

4-hydroxy-2-quinolones. 95. Synthesis, structure, and antitubercular properties of hetarylamides of 4-hydroxy-2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carboxylic acid

The optimal conditions for obtaining hetarylamides of 4-hydroxy-2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carboxylic acid are suggested on the basis of derivatographic investigations. The ¹H NMR spectra of the synthesized compounds, their spatial structure, and also the results of a study of their antitubercular properties are discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 874–886, June, 2006.     

4-Hydroxy-2-quinolones. 108. N-R-amides of 9-fluoro-1-hydroxy-5-methyl-3-oxo-6,7-dihydro-3H,5H-pyrido[3,2,1-ij]quinoline-2-carboxylic acid and their antitubercular activity

The reaction of 6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline with triethylmethanetricarboxylate gives di(9-fluoro-1-hydroxy-5-methyl-3-oxo-6,7-dihydro-3H,5H-pyrido[3,2,1-ij]quinolin-2-yl)methane and ethyl 9-fluoro-1-hydroxy-5-methyl-3-oxo-6,7-dihydro-3H,5H-pyrido[3,2,1-ij]quinoline-2-carboxylate from which alkyl-, dialkylaminoalkyl-, and hetarylamides as well as hydrazides were prepared. The structure and antitubercular properties of the compounds synthesized are discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1391–1407, September, 2006.     

Zinc‐catalyzed transformation of diarylphosphoryl azides to diarylphosphate esters and amides

We have developed a facile and efficient procedure for the synthesis of diarylphosphate esters and amides. Using Zn(acac)₂ as the catalyst, the reaction of diarylphosphoryl azides with aliphatic alcohols and phenols through an unusual P?N bond cleavage provided a number of diarylphosphate esters in good yields (22 examples, up to 94%). Additionally, various diarylphosphate amides were obtained from the corresponding amines in excellent yields as well (8 examples, up to 96%).     

4-Hydroxy-2-quinolones 113. Synthesis and antitubercular activity of N-R-amides of 4-hydroxy-6-methyl-2-oxo-1-propyl-1,2,5,6,7,8-hexahydroquinoline-3-carboxylic acid

A preparative method has been developed and the synthesis has been effected of anilides and heterylamides of 4-hydroxy-6-methyl-2-oxo-1-propyl-1,2,5,6,7,8-hexahydroquinoline-3-carboxylic acid. A comparative analysis has been carried out of the structure and antitubercular properties of the synthesized compounds and their analogs unsubstituted in the quinoline nucleus. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 405–414, March, 2007.     

A convenient synthesis of coumarin-3-carboxylic acids via Knoevenagel condensation of Meldrum's acid with ortho-hydroxyaryl aldehydes or ketones

Coumarin-3-carboxylic acids were obtained in high yields with excellent purity from ortho-hydroxybenzaldehydes and Meldrum's acid after a 2 h reflux in ethanol. The less reactive ketones were first reacted with alcoholic ammonia to form ketimines, which were then condensed with Meldrum's acid to generate 4-alkylcoumarin-3-carboxylic acids in moderate yields.     

Decarboxylation of indole-3-carboxylic acids under metal-free conditions

Abstract

Two reaction systems have been developed for the decarboxylation of indole-3-carboxylic acids. The decarboxylation can be achieved smoothly under K₂CO₃-catalyzed or acetonitrile-promoted basic conditions. It provided an efficient and simple method for the transformation of indole-3-carboxylic acids and the corresponding indoles were isolated with good to excellent yields. From the experimental facts, we put forward the possible reaction mechanism.     

Synthesis and anticancer properties of 7α-chloro-3-methyl-1,1-dioxoceph-3-em-4-carboxylic acid esters

The tert-butyl esters of 3-azidomethyl-, 3-isocyanatomethyl-, 3-chloromethyl-, and 3-p-nitrophenylvinyl-7α-chloro-1,1-dioxoceph-3-em-4-carboxylic acid, and also esters of 7α-chloro-3-methyl-1,1-dioxoceph-3-em-4-carboxylic acid, and of 7α-chloro-3-methyl-2-dimethylaminomethylene-1,1-dioxoceph-3-em-4-carboxylic acid have been synthesized. Results of cytotoxic screening of these compounds in relation to cancer and normal cells in vitro are correlated and analyzed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 259–273, February, 2007.     

Silver-catalyzed facile decarboxylation of coumarin-3-carboxylic acids

A simple and highly efficient protocol with mild reaction conditions has been developed that allows the smooth protiodecarboxylation of diversely functionalized coumarin-3-carboxylic acids. In the presence of catalytic amounts of Ag₂CO₃ and acetic acid, even un-activated coumarin-3-carboxylic acids were converted in good to excellent yields and with great preparative ease to the corresponding coumarin derivatives.