低价钛试剂促进下2-(2-硝基苯基)咪唑与席夫碱的反应

在低价钛试剂作用下,以四氢呋喃为溶剂,研究了2-(2-硝基苯基)咪唑与席夫碱的分子间还原偶联反应.结果发现席夫碱中C-N键的断裂优于其与硝基的偶联成环,生成了5,6-二氢化咪唑并[1,2-c]喹唑啉.     

Reaction of Methyl 5(6)-(4-Aminophenylthio)- 2-benzimidazolylcarbamate with Isocyanates

Methyl 5(6)-(4-aminophenylthio)-2-benzimidazolylcarbamate reacts with aliphatic and aromatic isocyanates to give mono- and disubstitution products. The former are formed by the reaction involving the aniline nitrogen and the latter, by the reaction involving both the aniline and benzimidazole nitrogens. Biological activity of the products was assessed.     

Synthesis of 3-acetonyl- and 3-(2-oxoethyl)glutarates

Several synthetic routes to 3-acetonyl- and 3-(2-oxoethyl)glutarates 1-5 have been explored. The most advantageous involves, as the key steps, the conjugate addition of an appropriately substituted vinylmagnesium bromide to an alkylidenemalonic ester, a bis-homologation of the resulting diester and, finally, the reductive ozonolysis of the carbon-carbon double bond. The synthesis can be satisfactorily conducted in good overall yield on a multigram scale.     

Reaction of Methyl 5(6)-(4-Aminophenylthio)-2-benzimidazolylcarbamate with Carboxylic Acid Chlorides

Methyl 5(6)-(4-aminophenylthio)-2-benzimidazolylcarbamate was reacted with carboxylic acid chlorides to obtain mono- and disubstitution products. The formation of the former involves the aniline nitrogen and of the latter, both the aniline and benzimidazole nitrogens. Biological properties of the products are studied.     

Synthesis and Characterization of Novel Methyl (3)5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates

Series of methyl 3- and 5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates were developed and regioselectively synthesized as novel heterocyclic amino acids in their N-Boc protected ester form for achiral and chiral building blocks. In the first stage of the synthesis, piperidine-4-carboxylic and (R)- and (S)-piperidine-3-carboxylic acids were converted to the corresponding β-keto esters, which were then treated with N,N-dimethylformamide dimethyl acetal. The subsequent reaction of β-enamine diketones with various N-mono-substituted hydrazines afforded the target 5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates as major products, and tautomeric NH-pyrazoles prepared from hydrazine hydrate were further N-alkylated with alkyl halides to give 3-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates. The structures of the novel heterocyclic compounds were confirmed by ¹H-, ¹³C-, and ¹⁵N-NMR spectroscopy and HRMS investigation.     

Crystal Structure of Methyl 3- (2-chlorophenyl )-3- (5, 5-dimethyl-3-hydroxy-2-cyclohexene- 1-one-2-yl) propionate

1INTRODUCTIONInorganicsolidsupportsascatalystshavebeenwellstudied,becauseoftheirap-plicationsinorganicsynthese('~".Recently,wehavereportedtheKnoevenagelcon-densationcatalysedbyKF-Al,O,['i.Inthispaper,wediscussedthecrystalstruc-tureofthetitlecomPoundsynthesizedbythereactionof2-chlorobenzaldehydey5,5-dimethyl-1,3-cyclohexanedioneandisopropylidenemalonateinmethanolcatalyzedbyKF-Alzo,'Inordertoconfirmthestructureofthetitlecompound,theX-raycrys-tallOgraphicstudywascarriedout.2EXPER1MEN…     

Preparation of 2(3)-O-[2-(hydroxyamino)-2-oxoethyl]- and 2(3)-O-[3-(hydroxyamino)-3-oxopropyl]dextran

Hydroxame derivatives of carboxymethyl- and carboxyethyldextrans have been prepared and characterized by elemental analysis as well as by IR and UV spectroscopy. The effect of reaction conditions on the products yield has been studied.     

Reaction of 2-(2-oxoethylidene)furan-3(2H)-ones with isopropylidenehydrazides of aromatic carboxylic acids: Synthesis of 3-hydroxy-3-(2-oxoethyl)-2,3-dihydropyridazin-4(1H)-ones

3-Hydroxy-3-(2-oxoethyl)-6-phenyl-2,3-dihydropyridazin-4(1H)-ones were obtained by the reaction of methyl 3-oxo-5-phenylfuran-2(3H)-ylideneacetate or 2-[2-(4-chlorophenyl)-2-oxoethylidene]-5-phenylfuran-3(2H)-one with benzoic or p-nitrobenzoic isopropylidenehydrazides. Equilibrium C₍₅₎H and C₍₅₎H₂ tautomeric forms were detected in solutions of the 4-chlorophenyl derivatives in DMSO-d₆. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1156–1158, August, 2007.     

Reaction of 3-(3-Arylpropenoyl)-2H-chromen-2-ones with Methyl 1-Bromocyclopentane-1-carboxylate and Zinc

Russian Journal of Organic Chemistry - The reaction of 3-(3-arylpropenoyl)-2H-chromen-2-ones with methyl 1-bromocyclopentane-1-carboxylate and zinc resulted in the isolation, after hydrolysis of...     

2'-O-[2-(amino)-2-oxoethyl] oligonucleotides

[structure: see text] Oligonucleotides with novel modifications, 2'-O-[2-(amino)-2-oxoethyl] (2'-O-NAc), 2'-O-[2-(methylamino)-2-oxoethyl] (2'-O-NMAc), 2'-O-[2-(dimethylamino)-2-oxoethyl] (2'-O-DMAc), and 2'-O-[2-[[2-(dimethylamino)ethyl]amino]-2-oxoethyl] (2'-O-DMAEAc), have been synthesized. These modified oligonucleotides exhibit high binding affinity to complementary RNA (and not to DNA) and considerably enhance the nuclease stability of oligonucleotides with t(1/2) > 24 h.     

Structure and Transesterification Reaction of Methyl 3-（Phenyldihalostannyl）propionates

The title compounds, PhX2SnCHECHECO2Me （X = C1, 1a; Br, 1b; I, 1c）, readily underwent transesterification into the corresponding analogues, PhX2SnCH2CH2CO2R when reacted with an alcohol ROH. The structural features of these compounds were described, and the possible mechanism of the novel transesterification was suggested.     

Synthesis of Methyl 2-(5-Arylidene-2,4-dioxotetrahydrothiazol-3-yl)propionates

A series of methyl 2-(arylidene-2,4-dioxotetrahydrothiazol-3-yl)propionates were prepared. A study of the 3D structure was performed. The log P values are given for all the synthesized compounds.     

Rearrangement in the series of 3-(2-aryl-2-oxoethyl)-3,4-dihydroquinoxalin-2(1H)-ones

4-Acetyl- and 4-succinyl-3-(2-aryl-2-oxoethyl)-3,4-dihydroquinoxalin-2(1H)-ones undergo the rearrangement into (Z)-2-(3-arylquinoxalin-2-ylidene)acetic acids accompanied by the elimination of the acyl groups. The nitration of 3-(2-oxo-2-phenylethyl)-3,4-dihydro-quinoxalin-2(1H)-one affords 5-nitro- and 7-nitro-2-carboxymethylidenequinoxalines. The bromination of quinoxalin-2-ones in AcOH gives 3-aryl-2-carboxymethylidenequinoxalines and the corresponding 7-bromo derivatives, with the former products predominating.     

New route to (3RS) (5R) (5-2H)- and (3RS) (5S) (5-2H)-mevalonolactones

The synthesis of mevalonolactone stereospecifically labeled at carbon 5 is described combining chemical reactions with an enzymatic reduction step.