One-step synthesis of substituted 4,7-bis[alkyl(aryl)imino]-3-oxa-6-thia-1-azaspiro[4.4]nona-1,8-dienes

Alkyl-(aryl) isocyanides react with benzoyl isothiocyanate in the presence of dialkyl acetylenedicarboxylates or dibenzoylacetylene in one-pot to afford highly substituted 4,7-bis[alkyl(aryl)imino]-2-phenyl-3-oxa-6-thia-1-azaspiro[4.4]nona-1,8-dienes, with double insertion of the isocyanide, in 38-45% yields (based on the isocyanide).     

Recyclization reactions of 2-(1-benzoylpyrrolidin- 2-ylidene)malononitrile

Acylation of pyrrolidin-2-ylidenemalononitrile with benzoyl chloride leads to the formation of 2-(1-benzoylpyrrolidin-2-ylidene)malononitrile. The obtained product was used as starting material in the synthesis of γ-aminopropylpyrazoles and pyrimidines.     

Synthesis and Antimicrobial Activity of 2-[5-(R-Benzyl)-4-oxo-1,3-thiazolidin-2-ylidene]-3-oxobutanenitrile and [2-(1-Cyano-2-oxopropylidene)-4-oxo-1,3-thiazolidin-5-ylidene]acetic Acid Derivatives

Russian Journal of Organic Chemistry - The reactions of 2-cyano-3-oxobutanethioamide with ethyl 3-aryl-2-bromopropanoates and dialkyl acetylenedicarboxylates afforded a combinatorial library of new...     

One-pot synthesis of novel (E)-3-(3,8a-dihydro-2H-oxazolo[3,2-a]pyridin-2-ylidene)chroman-2-one derivatives

An efficient synthetic procedure for the preparation of novel (E)-3-(3,8a-dihydro-2H-oxazolo[3,2-a]pyridin-2-ylidene)chroman-2-one derivatives was developed. A sequential one-pot, two-step tandem reaction starting from 3-(2-bromoacetyl)-2H-chromen-2-one derivatives synthesized, pyridine, and naphthols in the presence of triethylamine proceeded smoothly in acetonitrile under reflux conditions. In this process, 2-oxo-2H-chromen-3-yl)ethyl)pyridinium bromide derivatives as intermediate produced in situ, followed by Michael addition of naphthoxide anion and intramolecular cylization, resulted the corresponding products in good to high yields. All of the compounds were obtained in high purity without any use of more purification.     

[3 + 2]-Cycloaddition of azomethine ylide at 1,3-dimethyl-6-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-3a,9a-diphenyl-3,3a,9,9a-tetrahydroimidazo[4,5-e][1,3]thiazolo[3,2-b][1,2,4]triazine-2,7(1H,6H)-diones

[3 + 2]-Cycloaddition of azomethine ylide generated from formaldehyde and sarcosine at the double bond of 1,3-dimethyl-6-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-3a,9a-diphenyl-3,3a,9,9a-tetrahydroimidazo[4,5e][1,3]thiazolo[3,2-b][1,2,4]triazine-2,7(1H,6H)-diones occurs stereospecifically at the face opposite to the phenyl substituents. Product 3a crystallizes as a conglomerate.     

Highly Efficient and Mild Gold (I) Catalyzed Synthesis of 3,8-Diarylidene-2,7-dioxaspiro[4.4]nonane-1,6-diones

The gold-catalyzed cyclization of 2,2-bis(3-arylprop-2-yn1-yl)malonic acid has been proposed as an efficient approach to substituted 3,8-dibenzyl-2,7-dioxaspiro[4.4]nonane-1,6-diones. The reaction proceeds smoothly in mild reaction conditions to give the desired products in quantitative yields in the presence of variously substituted starting materials. In addition, the synthesis of γ-arylidene spirobislactone bearing different substituents on the two aromatic rings has been achieved. This kind of compound could be of great interest in pharmaceutical science given the widespread presence of this scaffold in bioactive natural and synthetic products.     

L-proline-catalyzed 1,3-dipolar cycloaddition of some Schiff bases to methyl 4-[1-oxo-2-(2-oxo-2,3-dihydro-1H-indol-3-ylidene)ethyl]phenylcarbamate

Russian Journal of Organic Chemistry -     

Efficient synthesis of (S,S)-2,8-diazabicyclo[4.3.0]nonane

An efficient synthetic route for moxifloxacin chiral intermediate via five steps was established. First, dehydration, N-acylation, and cyclization were combined in one pot to meet the industrial requirement. Then relatively low hydrogen pressure was employed in the catalytic hydrogenation reaction with high yield. Isopropanol/water system was used in resolution, which guaranteed high yield and perfect optical purity. The racemic process conducted by manganese dioxide and Pd/C successfully converted the undesired enantiomer into the racemate and hence the total yield increased remarkably. Furthermore, mild hydrogen transfer catalytic hydrogenation method was utilized in debenzylation process instead of high-pressure hydrogenation. Total yield of 39.0% was achieved, which was much higher than that of 29.0% in literature.     

Concise asymmetric synthesis of (5R)-6-hydroxy-3,8-dioxabicyclo[3.2.1]octane derivatives

[reaction: see text] A concise method to asymmetrically synthesize 6-hydroxy-3,8-dioxabicyclo[3.2.1]octane (HDBO) derivatives was devised.     

Direct synthesis of 3,5-diaryl-1,2,4-oxadiazoles using 1-(2-oxo-2-arylethyl)pyridin-1-iums with benzamidines

An efficient domino protocol for the synthesis of 1,2,4-oxadiazole derivatives from readily available 1-(2-oxo-2-arylethyl)pyridin-1-iums and amidine hydrochlorides was developed. In this practical approach, N-acyl amidine precursors were formed firstly via a simple nucleophilic substitution, without the purification of N-acylamidine intermediates, and the following intramolecularly dehydrative cyclization gave 1,2,4-oxadiazole derivatives in the presence of I₂/K₂CO₃/DMSO, which exhibited excellent functional group tolerance and proceeded under simple experimental conditions.     

Synthesis of 1H-1,4,7,10,13,16-hexaoxacyclooctadecaen-2-[2,3-f]indole,a new heterocyclic system

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1292–1293, September, 1992.     

Five-membered 2,3-dioxoheterocycles: XC. Reaction of 4,5-bis(methoxycarbonyl)-1H-pyrrole-2,3-diones with enaminoesters. crystal and molecular structure of 4-methyl 9-ethyl 7-benzyl-3-hydroxy-8-methyl-1-(4-methoxyphenyl)-2,6-dioxo-1,7-diazaspiro[4.4]nona-3,8-diene-4,9-dicarboxylate

1-Aryl-4,5-bis(methoxycarbonyl)-1H-pyrrole-2,3-diones react with ethyl 3-(benzylamino)but-2-enoate and ethyl 3-(benzylamino)-3-phenylacrylate giving 4-methyl 9-ethyl 1-aryl-7-benzyl-3-hydroxy-8-methyl- and 4-methyl 9-ethyl 1-aryl-7-benzyl-3-hydroxy-8-phenyl-2,6-dioxo-1,7-diazaspiro[4.4]nona-3,8-diene-4,9-dicarboxylates.