Fast and convenient base-mediated synthesis of 3-substituted quinolines

In a convenient method, 3-substituted quinolines are readily synthesized in a two-step process with initial oxazine formation and subsequent base-mediated cyclization.     

Convenient synthesis of 3-methyl-1-(4-pyridinyl)-2-butanone using phenyllithium as a metalating agent

3-Methyl-1-(4-pyridinyl)-2-butanone has been synthesized via a short and convenient method based upon acylation of 4-picoline by phenyllithium followed by reaction with ethyl isobutyrate. This procedure can be extended to the preparation of various alkyl pyridyl ketones, intermediates in the synthesis of potential anti-tumor 6-substituted 7H-pyridocarbazole dimers.     

A convenient large scale synthesis of 2,6-dimethyl-4-(trimethylstannyl)pyridine

Reaction of phosphorus oxychloride with 2,6-dimethylpyridine N-oxide hydrochloride ( 1 ) gave a mixture of 2-(chloromethyl)-6-methylpyridine ( 2 ) and 4-chloro-2,6-dimethylpyridine ( 3 ). Treatment of this mixture with triethylamine converted 2 to the quaternary salt 4 which was separated by water extraction leaving 3 which was subsequently reacted with trimethylstannyl sodium to yield 2,6-dimethyl-4-(trimethylstannyl)pyridine ( 6 ).     

A short and convenient chemoenzymatic synthesis of both enantiomers of 3-phenylGABA and 3-(4-chlorophenyl)GABA (Baclofen)

Both enantiomers of the pharmacologically active GABA analogues 4-amino-3-phenyl and 4-amino-3-(4-chlorophenyl)butyric acid (Baclofen) with high enantiomeric excesses were synthesized by a chemoenzymatic method involving α-chymotrypsin mediated kinetic resolutions of the corresponding 3-phenyl- and 3-(4-chlorophenyl)-4-nitrobutyric acid methyl ester precursors.     

A convenient and efficient conversion of diethyl [[[2-(3- or 4-pyridinyl)-4-pyrimidinyl]amino]methylene]propanedioates to higher homologs by base-catalysed transesterification

Base-catalysed transesterification of diethyl [[[2-(3- or 4-pyridinyl)-4-pyrimidinyl]amino]methylene]propanedioates gave higher homolog esters in high yields.     

A convenient synthesis of β-(trimethylsilyl)ethanol

A novel, simple and high yield synthesis of β-(trimethylsilyl)ethanol in pure form is reported.     

A convenient synthesis of 2-(alkylamino)pyridines

The synthesis of a series of 2-(alkylamino)pyridines (1) in three steps from 2-aminopyridine (4) is reported. The products were obtained in 67-91% overall yield from 4.     

A convenient synthesis of 3-amino-4-imino(thioxo)-imidazolidin-2-ones

Subsequent treatment of diethylphosphonopropyl α-aminonitriles with 1,1′-carbonyldiimidazole or 1,1′-carbonyl-di-(1,2,4-triazole) and hydrazines afforded substituted 3-amino-4-imino-imidazolidin-2-ones. Their acidic hydrolysis and their reactions with hydrogen sulfide are described.     

A convenient 3-step synthesis of (R)-7-hydroxycarvone from (S)-alpha-pinene

A convenient 3-step synthesis of (R)-7-hydroxycarvone (2) has been developed starting from (S)-alpha-pinene (7), using photooxygenation, oxidation, and fragmentation reactions. An improved synthesis of epoxy alcohol 6 and an unusual Ti(OiPr)(4) catalyzed hydroxy epoxide to keto alcohol rearrangement are also described.     

Synthesis and Crystal Structure of Rctt-1-(2-benzoxazolyl)-2-(4-chlorophenyl)-4-phenyl-3-(4-pyridinyl)cyclobutane

1INTRODUCTIONThephotodimerizationof1,2-bisarylethenederivativesisaconvenientwayforsynthesizingtetraarylsubstitutedcyclobutane.Forthisreason,thephotochemistryofstilbeneandstyrylpyridinederivativeshasbeenextensivelystudied[1,2].UpontheirradiationwithUVlight(?=300～400nm),thesemonomersareconvertedtohead-to-tailphotodimersinpolarsolventwithperfectyields.Inrecentyears,ourgrouphasbeenstudyingthephotodimerizationreactionsofheteroarylethenescontainingbenzoxazolyl[3]andphenyloxazolyl[4]groups.Itw…     

An improved synthesis of 1-(1,2,3,6-tetrahydro-1-methyl-4-pyridinyl)ethanone,isoarecolone

A convenient synthesis of 1-(1,2,3,6-tetrahydro-1-methyl-4-pyridinyl)ethanone, isoarecolone, starting with 4-acetylpyridine is presented. 4-Acetylpyridine was protected as the ketal followed by reaction with iodomethane to give the quaterary salt. The quaterary salt was reduced with sodium borohydride followed by deprotection to give isoarecolone in 80% overall yield.     

One-pot synthesis of 3-fluoro-4-(trifluoromethyl)quinolines from pentafluoropropen-2-ol and their molecular modification

Pentafluoropropen-2-ol (PFP) was prepared by the reaction of hexafluoroacetone (HFA) with Mg/TMSCl. The one-pot tandem sequential reactions of PFP via Mannich addition with aldimines followed by Friedel-Crafts cyclization and aromatization afforded the title quinolines. A variety of corresponding 3-substituted quinolines were derived from the title quinoline by nucleophilic substitution of 3-fluorine with nucleophiles. A defluorinative transformation of the 4-trifluoromethyl group of the title quinoline with hydrazine afforded pyrazoloquinoline.     

Synthesis and Transformations of 4-(4-Ethoxycarbonylphenylamino)- and 4-(2-Carboxyphenylamino)quinolines

Synthesis was performed of 4-(4-ethoxycarbonylphenylamino)- and 4-(2-carboxyphenylamino)-2-methylquinolines by reaction of 2-methyl-4-chloroquinoline with anesthesin and anthranilic acid. In concentrated sulfuric acid 4-(2-carboxyphenylamino)-2-methylquinoline underwent cyclization into 6-hydroxy-7-methylquinolino[3,2-c]quinoline, and the alkaline hydrolysis of 4-(4-ethoxycarbonylphenyl-amino)quinoline afforded 2-methyl-4-(4-carboxyphenylamino)quinoline.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 786–787.Original Russian Text Copyright © 2005 by Avetisyan, Aleksanyan, Ambartsumyan.     

Synthesis of 2- and 3-pyridinyl(aryl)methanones

A procedure was developed for the preparation of 2- and 3-pyridinyl(aryl)methanones by the reactions of aryllithium with methyl pyridinecarboxylate and methyl esters of substituted phenylcarboxylic acids.     

A convenient synthesis of certain 1-(β-D-ribofuranosyl)benzotriazoles

The synthesis of 5,6-dichloro-1-(β-D -ribofuranosyl)benzotriazole ( 4a ), 5,6-dimethyl-1-(β-D -ribofuranosyl)benzotriazole ( 4b ) and 1-(β-D -ribofuranosyl)benzotriazole ( 4c ) in good yield has been accomplished by the condensation of the appropriate 1-trimethylsilylbenzotriazole ( 1a, 1b , and 1c ) with 2,3,5-tri-O-acetyl-D -ribofuranosyl bromide (2) followed by subsequent deacetylation of the reaction products. The assignment of anomeric configuration and site of glycosidation for all nucleosides reported is discussed.     

A convenient synthesis of ethyl 2-(4-nitrophenyl)-3,4-disubstituted and c-fused thiophene-5-carboxylates

A convenient one step synthesis of the hitherto unknown ethyl 2-(4-nitrophenyl)-3,4-disubstituted and c-fused thiophene-5-carboxylates was achieved by the condensation of ethyl 4-nitrobenzylthioacetate with a variety of 1,2-dicarbonyl compounds using sodium ethoxide in refluxing ethanol.     

A convenient synthesis of methyl 2-hydroxy-4-oxo-4-(substituted phenyl) butanoates from malic acid

A synthesis of methyl 2-hydroxy-4-oxo-4-(substituted phenyl)butanoates has been accomplished using Friedel-Crafts acylation of substituted benzenes with 2-acetoxybutanoyl chloride.The key feature of this strategy is that various 4-arylbutanoates can be obtained conveniently,which are important intermediates for the synthesis of biologically active compounds including ACE inhibitors.     

A convenient synthesis of cis-4-(sulfomethyl)-piperidine-2-carboxylic acid: NMR assignment

cis-4-(Sulfomethyl)piperidine-2-carboxylic acid was obtained in 22% overall yield from 4-(hydroxymethyl)-pyridine via the o-silyl N-oxide and trimethylsilylcyanide. The cis configuration of 5 was unambiguously assigned by 200 MHz ¹H nmr and cosy experiments.