A synthesis of 5-hetaryl-3-(2-hydroxybenzoyl)pyrroles

A facile and versatile procedure for the synthesis of 5-hetaryl-3-(2-hydroxybenzoyl)-1H-pyrroles and 4-(2-hydroxybenzoyl)-1H-pyrrole-2-carboxylic acid derivatives was established on the basis of TMSCl promoted recyclization of 3-formylchromone with various hetarylmethylamines and glycine derivatives.     

Synthesis of polysubstituted pyrroles from sulfinimines (N-sulfinyl imines)

Polysubstituted 2-carboxylate and 2-phosphonate pyrroles are prepared by aromatization of the corresponding 3-oxo 2-carboxylate and 2-phosphonate NH-pyrrolidines using air. Reaction of electrophiles with 3-oxo pyrrolidine dianions readily introduces substituents, regioselectively at C-4 in these pyrrolidines.     

Yb(OTf)3-catalyzed synthesis of pyrroles under solvent-tree conditions

Ayb(Otf)3-catalyzed approach for the synthesis of pyrroles under solvent-free conditions was achieved,which could afford the desired products with yields ranged from moderate to excellent.     

Synthesis and Properties of 2-Alkyl-1-(2-aminoethyl)pyrroles

3-Chloropropenyl alkyl ketones or 2-methoxy-3-chloropropyl alkyl ketones in reaction withethylenediamine furnish previously unknown 2-alkyl-1-(2-aminoethyl) pyrroles. Their reaction with 2'2'-dichlorodiethyl ether gave rise to 2-alkyl-1-(2-morpholinoethyl)pyrroles, with anhydrides ofdicarboxylic acids the corresponding amidoacids and imides of dicarboxylic acids were obtained.     

Synthesis of optically active 6-substituted 2-(aminomethyl)chromans

Three novel, optically active, 6-substituted 2-(aminomethyl)chromans were synthesized from readily available chroman 2-carboxylic acid precursors. These chroman-containing primary amines are useful building blocks for the synthesis of chroman-derived pharmaceutical agents.     

Synthesis of functionalized pyrroles and 6,7-dihydro-1H-indol-4(5H)-ones by reaction of 1,3-dicarbonyl compounds with 2-azido-1,1-diethoxyethane

The condensation of 1,3-dicarbonyl compounds with 2-azido-1,1-diethoxyethane and subsequent cyclization allowed an efficient synthesis of a variety of pyrroles and 6,7-dihydro-1H-indol-4(5H)-ones.     

Synthesis of polysubstituted pyrroles via a gold(I)-catalyzed tandem three-component reaction at room temperature

A gold(I)-catalyzed three-component reaction of β-nitrostyrenes with 1,3-dicarbonyl compounds and primary amines to form polysubstituted pyrroles has been developed at room temperature in ethanol. The key advantages of the three-component reaction are the mild reaction conditions and environm entally safer solvent     

Synthesis of 1-arylmethyl-2-(2-cyanoethyl)aziridines and their rearrangement into novel 2-(aminomethyl)cyclopropanecarbonitriles

1-Arylmethyl-2-(bromomethyl)aziridines were transformed into novel 2-(2-cyanoethyl)aziridines upon treatment with alpha-lithiated trimethylsilylacetonitrile in THF in an efficient and straightforward approach. The latter aziridines underwent ring opening by reaction with benzyl bromide in acetonitrile, affording 5-amino-4-bromopentanenitriles through a regiospecific ring opening of intermediate aziridinium salts by bromide. Further elaboration of these gamma-bromonitriles resulted in the synthesis of novel 2-[N,N-bis(arylmethyl)aminomethyl]cyclopropanecarbonitriles in high yields by means of a 1,3-cyclization protocol upon treatment with KOtBu in THF.     

Synthesis and X-Ray Diffraction Study of 2-(2-Acyl-1-phenylethenyl)pyrroles

Pyrroles add to 2-acyl-1-phenylacetylenes on the surface of silicon dioxide at 20-90°C affording structurally stable Z-isomers of 2-(2-acyl-1-phenylethenyl)pyrroles containing a strong intramolecular hydrogen bond. The geometry of these molecules was established by X-ray diffraction analysis of a single crystal of 2-(2-benzoyl-1-phenylethenyl)-4,5,6,7-tetrahydroindole.     

Silica sulfuric acid (SSA) as a solid acid heterogeneous catalyst for one-pot synthesis of substituted pyrroles under solvent-free conditions at room temperature

A variety of N-substituted pyrroles have been synthesized by reacting γ-diketones with amines, diamines or triamine in the presence of silica sulfuric acid (SSA) at room temperature under solvent-free conditions. The experiment protocol features simple operations, and the products are isolated in high to excellent yields (70-98%).     

A facile preparation of 2-(2-arylethyl)- and 2-(aminomethyl)indoles

An important process for the acid catalyzed cleavage of the benzoyl group from 3-benzoylindoles in high yield is identified and its application for the facile syntheses of 2-substituted indoles is demonstrated by preparing some 2-(2-arylethyl)- and 2-(aminomethyl)indoles from 1,3-dibenzoyl-2-bromomethylindole (7).     

Electronic absorption spectra of protonated 2-(2-furyl)pyrroles, 2-(2-thienyl)pyrroles,and 2-arylpyrroles

Protonation of 2-(2-furyl)-, 2-(2-thienyl)-, and 2-arylpyrroles by sulfuric acid in ethanol was studied using electronic absorption Spectroscopy in the UV and visible regions. Pyrroles with heteroaromatic substituents are protonated at the -positions of pyrrole and the heterocycle, resulting in the appearance of additional long-wave spectral bands. In the series of 2-arylpyrroles protonation capability is determined by the electronic effect of the phenyl ring substituents.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1060–1062, June, 1993.     

An Efficient Synthesis of Optically Pure (R)- and (S)-2-(aminomethyl)alanine ((R)- and (S)-ama) and (R)- and (S)-2-(aminomethyl)leucine ((R)- and (S)-aml)

An efficient synthesis of enantiomerically pure (R)- and (S)-2-(aminomethyl)alanine ((R)- and (S)-Ama) 1a and (R)- and (S)-2-(aminomethyl)leucine ((R)- and (S)-Aml) 1b is described (Schemes 1 and 2). Resolution of the racemic amino acids was achieved using L -phenylalanine cyclohexylamide ( 2 ) as chiral auxiliary. The free amino acids 1a, b were converted to the N^α-Boc,N^γ-Z-protected derivatives 11a, b (Scheme 3) ready for incorporation into peptides. Based on the three crystal structures of the diastereoisomeric peptides 8a, 8b , and 9b , the absolute configurations in both series were determined. β-Turn type-I geometries were observed for structures 8b and 9b , whereas 8a crystallized in an extended backbone conformation.     

Synthesis of mono- and bis(aminomethyl)dioxanes fromN-[3-(2-chloroethoxy)-2-hydroxypropyl]sulfamates

N-Substituted aminomethyl- and 2,5-bis(aminomethyl)-1,4-dioxanes were prepared by cyclization of the corresponding potassiumN-[3-(2-chloroethoxy)-2-hydroxypropyl]sulfamates under the action of an alkaline agent followed by alcoholysis of the resulting sulfamic acids.     

Synthesis of furans, pyrroles and pyridazines by a ruthenium-catalysed isomerisation of alkynediols and in situ cyclisation

Alkyne-1,4-diols are readily available substrates which are isomerised to 1,4-diketones using Ru(PPh₃)₃(CO)H₂/xantphos as a catalyst. In situ cyclisation into furans, pyrroles and pyridazines has been achieved under suitable conditions.     

Synthesis and insecticidal activity of 4-(aminomethyl)-2H-1-benzothiopyran-2-ones (thiocoumarins) and related compounds

Bromination of 4-methyl-2H-1-benzothiopyran-2-ones (4-methylthiocoumarins) with bromine under irradiation of high-pressure mercury lamp gave 3-bromo-4-methylthiocoumarin, which reacted with secondary amine to give 4-(aminomethyl)thiocoumarins. The structure was determined by X-ray crystallographic analysis. A series of 4-methylthiocoumarin and related compounds were tested for insecticidal activity, and 4,6-dimethylthiocoumarin shows the most significant insecticidal activity against Nilaparvata lugens and Aphis gossypii. An introduction of an aminomethyl group in thiocoumarin results in improvement of activity against Tetranychus urticae and Spodoptera litura.     

Synthesis and crystal structure of 1-(aminomethyl)vinylphosphonic acid

A highly efficient and versatile approach to the synthesis of 1-(aminomethyl)vinylphosphonic acid, a constituent of the antibiotic A53868A, is reported. In the crystal, molecules of the acid are linked by strong, linear, symmetric hydrogen bonds involving hydrogen atoms of the phosphonic group.     

Synthesis and anti-HIV-1 activity of a series of 1-(alkoxymethyl)-5-alkyl-6-(arylselenenyl)uracils and -2-thiouracils

A series of 1-(alkoxymethyl)-5-alkyl-6-(phenylselenenyl)uracils and -2-thiouracils modified at the 3- and/or 5-position of the C-6 phenylselenenyl ring with methyl or fluoro substituent has been synthesized and tested for their ability to inhibit HIV-1 replication. Lithiation of the acyclic uracil and 2-thiouracil derivatives 11-14 and 27-32 with lithium diisopropylamide or lithium bis(trimethylsilyl)amide followed by reaction with an appropriate diaryl diselenide afforded 6-arylselenenyl compounds 18-26 after removal of the tert-butyldimethylsilyl protecting group and 35-47 . Compounds 48-54 were prepared from compounds 38-44 by oxidative hydrolysis of the thione function. Of these compounds, 50 inhibited HIV -1 replication in human T₄ lymphoblastoid cells at a 50% effective concentration (EC₅₀) of 0.0047 μM with a selectivity index of >42600.     

Synthesis of 5-alkyl(or aryl)pyrrolo[1,2-a]quinoxalin-4(5H)-ones by denitrocyclisation of N-alkyl(or aryl)-1-(2-nitrophenyl)-1H-pyrrole-2-carboxamides. Evidence of a Smiles rearrangement

An efficient method for the synthesis of hitherto unknown alkyl(or aryl)pyrrolo[1,2-a]quinoxalin-4(5H)-ones 8a-g, 16 and 17 has been established. The method is based on the synthesis of the corresponding N-alkyl(or aryl)-1-(2-nitrophenyl)-1H-pyrrole-2-carboxamides 3a-c and 7a-c,e which undergo denitrocyclisation with NaH in DMF in 4.5 or 2 h. When 3a was treated with NaH in DMF for 30 min the product of a Smiles rearrangement, 9, was isolated. Under similar conditions but for 4.5 h 9 was converted into 8a. This confirms the involvement of a Smiles rearrangement during the denitrocyclisation process. Conversion of 3b into isomeric pyrroloquinoxalinones 12 and 13 confirms a process involving two pathways, direct denitrocylisation of 3b and Smiles rearrangement of 3b followed by denitrocylisation, respectively. Furthermore, denitrocylisation of 7d into pyrroloquinoxalinones 16 and 17 suggests that similar cyclisation pathways are followed by N-arylcarboxamides.