Synthesis of enantiomers of 6-nitro- and 6-amino-2-methyl-1,2,3,4-tetrahydroquinolines

Enantiomers of 2-methyl-6-nitro-1,2,3,4-tetrahydroquinoline have been obtained by kinetic resolution of racemic 2-methyl-1,2,3,4-tetrahydroquinoline in acylation with acyl chlorides of N-protected amino acids followed by regioselective nitration of the diastereoisomeric amides and acidic hydrolysis. The introduction of a trifluoroacetyl protecting group into the position 1 of the enantio pure nitro compound followed by the reduction led to (S)-6-amino-2-methyl-1-trifluoroacetyl-1,2,3,4-tetra-hydroquinoline in a high yield.     

Synthesis of 2-alkyl(aryl,hetaryl)-4-methyl-1,2,3,4-tetrahydroquinolines

We have developed a preparative, three stage of synthesis of substituted 1,2,3,4-tetrahydroquinolines. Treatment of N-aryl-imines with allylmagnesium bormide gave N-aryl-N-alkenylamines which were cyclized to the tetrahydroquinolines. The configurations and conformations of the 4-methyl-1,2,3,4-tetra-hydroquinolines containing different 2- substituents have been determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 73–78, January, 1994.     

Synthesis of 7-methyl-6-indolopterin and 7-methyl-6-indoloquinoxaline

The first syntheses of indolopterin and indoloquinoxaline, two important and dissimilar diheterocycles linking C-2 of indole with C-6 of pterin (significant positions for showing biological activity), and quinoxaline, respectively, have been achieved based on two classical reactions. The introduction of a keto methyl group on to the 6-position of pterin and quinoxaline followed by Fischer indole synthesis led to these target diheterocycles. These indole-substituted diheterocycles will significantly increase the electron density on the pterin-5-N and quinoxazoline-2-N, which may change the redox properties of pterin and quinoxaline, and also the electron-withdrawing pterin or quinoxazoline should make the indole NH more acidic.     

Unusual phenomena during the resolution of 6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline (FTHQ): thermodynamic-kinetic control

6-Fluoro-2-methyl-1,2,3,4-tetrahydroquinoline (FTHQ) was resolved in several different solvents by tartaric acid derivatives as the most common acidic resolving agents available in industrial quantities. Strong reaction kinetics and solvent dependence were observed, curiously without solvation. In possession of these findings, an economic resolution process is proposed, which is completed by the incorporation of a racemization step.     

R 和 s-1-(3'-溴-4'-甲氧基)苄基-2-甲基-6-甲氧基-7-羟基-1, 2,3,4-四氢异喹啉的合成

本文报道了R和S-1-(3'-溴-4'-甲氧基)苄基-2-甲基-6-甲氧基-7-羟基-1,2,3,4-四氢异喹啉的合成。     

Convenient synthesis of 1,3-substituted-6-phenylpiperazin-2-ones

The convenient preparation of novel 6-phenylpiperazin-2-ones from simple starting materials via a practical two-step procedure is presented. This methodology involves an initial alkylation of 2-bromoacetophenone with an amino ester followed by a one-pot reductive amination and cyclization step to furnish the desired substituted piperazinones.     

2-甲基-6-(3-甲基-2-丁烯基)对苯二醌的合成

以邻甲基苯酚为原料,与1-氯-2-甲基-2-丁烯反应生成2-甲基-6-(3-甲基-2-丁烯基)苯酚,然后催化氧化得到目标产物2-甲基-6-(3-甲基-2-丁烯基)对苯二醌。该合成路线简单,易于操作,最终收率51%。     

Synthesis and antibacterial activity of novel 7-substituted-6-fluoro-1- fluoromethyl-4-oxo-4H-[1,3thiazeto[3,2-a]quinoline-3-carboxylic acid derivatives

A series of 7-substituted-6-fluoro-1-fluoromethyl-4-oxo-4H- [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid derivatives (2a-1) was prepared and evaluated for antibacterial activity. These compounds were obtained by deacylation of 4-benzoyloxy-2-(1-chloro-2-fluoroethyl)thio-6,7- difluoroquinoline-3-carboxylate (10) and subsequent intramolecular cyclization followed by substitution with cyclic amines and then hydrolysis. The intramolecular cyclization reaction of 18, one of the diastereomers (17, 18) revealed that the cyclization reaction proceeded through an inversion to afford (-)-11a in good chemical and optical yield. The enantiomers of 2a were prepared from the enantiomers of 11a, which were obtained by the optical resolution of the racemate using high-performance liquid chromatography (HPLC). Compounds 2a,b showed excellent in vitro and in vivo antibacterial activity against both gram-negative and gram-positive bacteria including quinolone and Methicillin-resistant Staphylococcus aureus.     

Synthesis of 5-, 6- and 7-substituted-2-aminoquinolines as SH3 domain ligands

The Src homology 3 (SH3) domains are small protein-protein interaction domains that mediate a range of important biological processes and are considered valuable targets for the development of therapeutic agents. We have been developing 2-aminoquinolines as ligands for SH3 domains--so far the only reported examples of entirely small-molecule ligands for the SH3 domains. The highest affinity 2-aminoquinolines so far identified are 6-substituted compounds. In this article, the synthesis of several new 2-aminoquinolines, including 5-, 6- and 7-substituted compounds, for Tec SH3 domain ligand binding studies is presented. As a part of the synthetic investigation, the utility of different methods for the synthesis of 2-aminoquinolines was explored and potentially powerful methods were identified for the synthesis of 2-aminoquinolines with diverse functionality. Of the compounds prepared, the 5-substituted-2-aminoquinolines generally bound with similar affinities to unsubstituted 2-aminoquinoline, whilst the 7-substituted compounds generally bound with similar or lower affinity than unsubstituted 2-aminoquinoline. However, the 6-substituted-2-aminoquinolines generally bound with significantly higher affinity than unsubstituted 2-aminoquinoline. In addition, one 6-substituted-N-benzylated-2-aminoquinoline was also tested for SH3 binding and some evidence for the formation of additional contacts at other regions of the SH3 domain was found. These results provide new and useful SAR information that should greatly assist with the challenge of developing high affinity small-molecule ligands for the SH3 domains.     

Synthesis of 5-Alkyl-1,3-bis[2-hydroxy-3-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-3-yl)propyl]-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-diones

6-Methyluracil sodium salt reacts with 1,3-bis(3-chloro-2-hydroxypropyl)-6-methyluracils in DMF, yielding products of alkylation at the nitrogen atom in position 3 of the uracil ring.     

A Convenient One Step Synthesis of 1,3-Diaryl-6-methyl-4-oxo-1,2,3,4-tetrahydro-2-thioxofuro [2,3-d] Pyrimidines

1,3-Diaryl-6-methyl-4-oxo-1,2,3,4-tetrahydro-2-thioxofuro (2,3-d) pyrimidines have been synthesised in one step in good yield by the reaction of 1,3-diaryl-1,3-dihydro-2-thioxo-2H,5H-pyrimidine-4,6-diones with chloroacetone in presence of triethylamine.     

Synthesis of 1,2,3,4-tetrahydroquinolines and 1,2,3,4-tetrahydro- 1,6-naphthyridines by a directed lithiation reaction

N-(tert-butoxycarbonyl)anilines (7), are easily converted in a one pot reaction sequence into the N- (tert-butoxycarbonyl)-1,2,3,4-tetrahydroquinolines (8), by directed ortho lithiation followed by reaction with 1- chloro-3-iodopropane, hence providing a new versatile quinoline ring nucleus synthesis. In an analogous reaction 2-N-(tert-butoxycarbonyl)- and an 2-N-(pivaloylamino) pyridine are converted to 1,2,3,4-tetrahydro-1,6- naphthyridines.     

Synthesis and structure of 2-aryl-2,4-dimethyl-1,2,3,4-tetrahydroquinolines and 1,3-disubstituted indenes

It has been shown that the intramolecular cyclization of N-(1-arylbutenyl)arylamines under acid catalysis conditions may proceed in two directions with the formation of 2-aryl-2,4-dimethyl-1,2,3,4-tetrahydroquinolines and 1,3 disubstituted indenes.     

Synthesis of 2- and 3-substituted-1,2,3,4-tetrahydrodibenzo[f,h]isoquinolines

Some 2- and 3-substituted-1,2,3,4-tetrahydrodibenzo[f,h]isoquinolines were prepared by a synthetic scheme involving a selective Borch reduction of an amide to the corresponding amine and a Friedel-Crafts cyclization to obtain the dibenzo[f,h]isoquinoline system. The title compounds, which have a similarity to the cell growth inhibitory alkaloid cryptopleurine, failed to exhibit significant protein synthesis inhibitory activity.     

Synthesis of new trans-2-benzyl-3-(furan-2-yl)-4-substituted-1,2,3,4-tetrahydroisoquinolinones

The reaction of homophthalic anhydride and N-(furan-2-yl-methylidene)- benzylamine in different solvents and varying temperatures was studied in detail. Mixtures of the expected trans- and cis-1,2,3,4-tetrahydroisoquinoline-4-carboxylic acids trans-5 and cis-5, along with by-products 6 and 7 were obtained in dichloroethane or benzene. In pyridine, used for the first time, the reaction became completely diastereoselective, giving only the trans isomer. The carboxylic acid group of trans-5 was transformed in four steps into cyclic aminomethyl groups which yielded various new tetrahydroisoquinolinones trans- 11a-g, incorporating both a known fragment of pharmacological interest and various pharmacophoric substituents.     

Synthesis of some new 2-substituted-4-sulfamoylphenylazo-thiophene and/or thiazole derivatives as antibacterial agents

Benzoylacetone has been reacted with phenyl isothiocyanate to afford two different thiocarbamoyl derivatives (α-phenylthiocarbamoyl benzoylacetone and benzoyl thioacetanilide) depending upon the base used to perform the reaction. Several new 2-substituted-4-sulfamoylphenylazo-thiophene and/or thiazole derivatives were synthesized by heterocyclization of the thiocarbamoyl derivatives with various halogenated reagents. The synthesized compounds were screened for their antibacterial activities; they showed accepted activities with respect to the control drugs.