Synthesis of methyl esters of 5-aroyl-6-aryl-2-oxo-1,2,3,6-tetra-hydropyrimidine-4-carboxylic acids

Methyl esters of 5-aroyl-6-aryl-2-oxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acids were synthesized from three component mixtures of methyl esters of aroylpyruvic acids, urea, and substituted benzaldehydes. 8-Hydroxy-4,5-diphenyl-3,4-dihydropyrimido[4,5-d]pyridazin-2(1H)-one was synthesized by the reaction of 5-benzoyl-2-oxo-6-phenyl-1,2,3,6-tetrahydropyrimidin-4-carboxylate with hydrazine hydrate.     

Synthesis of N,6-diaryl-4-methyl-2-thioxo-1,2,3,6-tetrahydropyrimidine-5-carboxamides

Russian Journal of Organic Chemistry -     

Synthesis of 2-substituted 7,7-dimethyl-5-oxo-5,6,7,8-tetrahydroquinoline-4-carboxylic acids

2-Substituted 7,7-dimethyl-5-oxo-5,6,7,8-tetrahydroquinoline-4-carboxylic acids were synthesized by reaction of acyl- and aroylpyruvic acids with 3-amino-5,5-dimethylcyclohex-2-en-1-one. A plausible mechanism of their formation was proposed on the basis of ab initio quantum-chemical calculations.     

Synthesis and reactions of 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones

Cycloacylation of N-R-3-oxo-3-phenylpropanethioamides by diethyl ethoxymethylenemalonate occurs selectively to form 1-R-3-benzoyl-5-ethoxycarbonyl-6-oxo-1,2,3,6-tetrahydropyridine-2-thiones which are convenient starting materials for the synthesis of bi-and tricyclic hetero systems including the previously unknown 9-R-7-ethoxycarbonyl-5-phenyl-8,9-dihydropyrido[2,3-d][1,2,4]triazolo[1,5-a]-pyrimidin-8-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1660–1669, November, 2007.     

2-methylpyridinium 5-(2,4-dinitrophenyl)-6-oxo-2-thioxo-1,2,3,6-tetrahydropyrimidin-4-olate: Synthesis,crystal structure,and biological evaluation

The titled complex is synthesized from the ethanolic solutions of 1-chloro-2,4-dinitrobenzene, 2-thiobarbituric acid, and 2-methylpyridine and characterized by spectral and elemental analyses. The single crystal X-ray diffraction results for the complex are compatible with the spectral observations. The titled complex exhibits anticonvulsant activity and reduces all phases of convulsion even at a low dosage. Acute toxicity studies of the complex are performed to understand the safer dose concentration for clinical trials.     

A convenient synthesis of 3-alkyl-2,3-dihydro-2,4-dioxo-6-phenyl-, 3-alkyl-2,3-dihydro-4-oxo-6-phenyl-2-thioxo-, and 3-alkyl-2-arylimino-2,3-dihydro-4-oxo-6-phenyl-4H-1,3-thiazines

The reactions of 1-alkylamino-1-alkylthio-3-phenylpropene-3-thiones 3 with thiophosgene and phosgene in toluene, followed by treatment of the reaction mixture with triethylamine gave 3-alkyl-2,3-dihydro-4-oxo-6-phenyl-2-thioxo- 4 , 3-alkyl-2,3-dihydro-2,4-dioxo-6-phenyl-4H-1,3-thiazines 5 , respectively in good to excellent yields. Similarly treatment of compounds 3 with N-arylimidoyl dichloride in benzene at room temperature gave 3-alkyl-2-arylimino-2,3-dihydro-4-oxo-6-phenyl-4H-1,3-thiazines 6 in excellent yields. The reactions of compounds 3 with oxalyl chloride in toluene gave also 5 in good yields.     

Multicomponent Synthesis of 2,5-Dioxo- and 4-Aryl-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinazolines

Ten 2,5-dioxo- and 4-aryl-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinazolines have been synthesized in three-component interactions of 1,3-cyclohexanedione or dimedone, urea or thiourea, and substituted benzaldehydes (3-bromo-, 4-bromo-, 4-fluoro-, 4-methoxy-, 3,4-methylenedioxy-, and 3-nitro-). 9-Aryl-4,5-dioxo-1,2,3,4,5,6,7,8-octahydro-9H-xanthenes were also formed in these reactions.     

Synthesis of substituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines and 4-oxo-3,4-dihydroquinazoline-2-thioles

We have developed a liquid-phase synthesis of combinatorial libraries of new disubstituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines and trisubstituted 4-oxo-3,4-dihydroquinazoline-2-thioles. The former were prepared using two general procedures: (i) cyclization of substituted methyl anthranilates with isothiocyanates, or (ii) cyclization of substituted 2-(methylcarboxy)benzeneisothiocyanates with primary amines or hydrazines. 4-Oxo-3,4-dihydroquinazoline-2-thioles were prepared by S-alkylation of disubstituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines with alkyl or aryl halides. The hydrolysis of methyl benzimidazo[1,2-c]quinazoline-6(5H)-thione-3-carboxylate led to the corresponding acid. This acid was utilized in the synthesis of new benzimidazo[1,2-c]quinazoline-6(5H)-thione-3-carboxamide and S-substituted 6-mecaptobenzimidazo[1,2-c]quinazoline-3-carboxamide libraries.     

Synthesis and antimicrobial activity of 6-aryl-3,4-dimethyl-N-phenyl-2-oxo-1,2,3,6-tetrahydropyrimidine-5-carboxamides

Three-component reaction of acetoacetanilide, aromatic aldehydes, and N-methylurea afforded 6-aryl-3,4-dimethyl-N-phenyl-2-oxo-1,2,3,6-tetrahydropyrimidine-5-carboxamides. IR, ¹H NMR spectroscopy, mass spectrometry, and X-ray diffraction analysis data confirmed the structure of the compounds obtained. Antimicrobial activity of these compounds was investigated.     

Synthesis of diethyl 6-aryl-2-oxo-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylates

Reaction of diethyl oxalylacetate sodium salt with aromatic aldehydes and urea led to the formation of diethyl 6-aryl-2-oxo-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylates.     

Synthesis and reactions of 7-substituted 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acids as an antibacterial agent

1-Cyclopropyl- and 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acid derivatives having a sulfinyl or sulfonyl group at C-7 were synthesized from 2,6-dichloro-5-fluoronicotinic acid derivatives by the route involving the Dieckmann-type cyclization. The displacement reactions of these compounds with pyrrolidine and piperidine gave mainly the 7-(1-pyrrolidinyl)- and 7-(1-piperidinyl)-1,8-naphthyridine derivatives 24-27 , respectively. Enoxacin, a potent antibacterial agent, was also synthesized with the analogous route.     

Synthesis and structure of 3-allenyl-4-aryl-7,7-dimethyl-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinoline-3-carbonitriles

3-Allenyl-4-aryl-7,7-dimethyl-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinoline-3-carbonitriles were synthesized via [3,3]-sigmatropic rearrangement of 4-aryl-7,7-dimethyl-5-oxo-2-(prop-2-yn-1-ylsulfanyl)-1,4,5,6,7,8-hexahydroquinoline-3-carbonitriles. The structure of 3-allenyl-7,7-dimethyl-4-(2-nitrophenyl)-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinolin-3-carbonitrile was determined by X-ray analysis.     

Synthesis and antibacterial activity of new 5-substituted 1-cyclopropyl-6-fluoro-7-piperazinyl-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acids

The 5-hydroxymethyl and the 5-formyl-1-cyclopropyl-6-fluoro-7-piperazinyl-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acids have been prepared via a 5-trimethylsilyl group and were tested in vitro as potential antibacterials.     

Reactivity of 6-anisyl-5-cyano-4-oxo-2-thioxo-1,2,3,4-tetrahydro-pyrimidine to wards some electrophiles and nucleophiles

The title compound was subjected to react with some electrophiles and nucleophiles, such as alkyl halides, ethyl chloroacetate or amines, hydrazines etc. The resulting compounds were used in further syntheses for the purpose of obtaining some new types of heterocycles with possible biological and pharmaceutical activities.     

Coordination compounds of hydrazine derivatives with transition metals. Part 27. Coordination chemistry of 4-amino-3-alkyl-5-thio-1,2,4-triazolines and 4-amino-5-oxo-3-thioxo-6-alkyl-2,3,4,5-tetrahydro-1,2,4-triazines

Summary Mono-, bis- and tris-ligand nickel(II) and cobalt(II) complexes with 4 amino-3-alkyl-5-thio-1,2,4-triazolines (HRL) (R=H, Me, or Et) and 4-amino-5-oxo-3-thioxo-6-methyl-2,3,4,5-tetrahydro-1,2,4-triazine (HL') have been prepared and characterized. In these complexes both HRL and HL' are in the neutral thione form. Nickel(II) and cobalt(II) complexes with mononegative thiolate ligands have been also isolated.The reaction of HL' with copper(II) salts in a molar ration of 11 results in the formation of [Cu(HL')X] (X=Cl or Br) and Cu(L')X (X=NO₃ or CH₃COO). However, in the presence of a large excess of HL' the reaction proceeds with partial reduction of Cu^II and both [Cu(HL')X₂] and [Cu(HL')₂]X have been isolated and characterized. The mechanism of copper(II) reduction by HL' is discussed.     

Synthesis of 2-substituted 4-quinazolone-5-carboxylic acids as inhibitors of DNA-gyrase

A series of 4-quinazolone-5-carboxylic acids were designed as bacterial DNA gyrase inhibitors. The syntheses of the target compounds were accomplished by reacting 3-aminophthalimide with aroyl chlorides followed by rearrangement of the resulting 3-acylaminophthalimides under basic conditions. The designed compounds showed moderate DNA gyrase inhibitory activity.