Practical synthesis of methyl(E)-2-(3-(3-(2-(7-chloro-2- quinolinyl)ethenyl)phenyl)-3-oxopropyl)benzoate,a key intermediate of Montelukast

A novel and practical synthetic route is presented for the preparation of methyl-(E)-2-(3-(3-(2-(7-chloro-2-quinolinyl)ethenyl) phenyl)-3-oxopropyl)benzoate,the key intermediate of Montelukast,a leukotriene antagonist.The main diarylpropane framework was prepared via a polarity conversation reaction resulting in an acyl anion equivalent followed by a nucleophilic substitution reaction.The overall yield of this approach was 61%.This method is simple for operation and suitable for industrial production.     

Reactions of 3-(4-Aryl-2-thiazolyl)- and 3-(2-Benzothiazolyl)-2-iminocoumarins with N-Nucleophiles

The reaction of 3-(4-aryl-2-thiazolyl)- and 3-(2-benzothiazolyl)-2-iminocoumarins with N-nucleophiles was studied. This reaction gives 2-N-substituted 3-(4-aryl-2-thiazolyl)- and 3-(2-benzothiazolyl)iminocourmarins. N-Nucleophiles such as arylamines, heterocyclic amines, and hydrazine derivatives undergo this reaction.     

Synthesis of (2E)-2-(tetrafluoroethylidene)-3,3-bis(trifluoromethyl)-2,3-dihydrothiazolo[3,2-a]benzimidazole

The reaction of benzimidazoline-2-thione with perfluoro-2-methylpent-2-ene in the presence of triethylamine afforded (2E)-2-(tetrafluoroethylidene)-3,3-bis(trifluoromethyl)-2,3-dihydrothiazolo[3,2-a]benzimidazole whose structure was confirmed by X-ray diffraction analysis. The reaction pathways are discussed.     

2-(Acylmethylmercapto)-3-amino- and 2-(acylmethylmercapto)-3-acetamidopyridines

The reaction of 2-mercapto-3-acetamido-5-(or 6-)chloropyridines with phenacyl bromide and substituted phenacyl bromides yielded 2-(phenacylmercapto)-3-acetamidopyridines, while the reaction of the former with -chloroacetoacetic ester yielded 2-(carbethoxyacyl-methylmercapto)-3-acetamidopyridlnes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1391–1394, October, 1971.     

Copper-catalyzed aerobic oxidative dehydrogenation for conversion of 2-(alkylthio)-1,4-dihydropyrimidines to 2-(alkylthio)pyrimidines

A simple and efficient aerobic oxidative dehydrogenation reaction method for the conversion of 2-(alkylthio)-1,4-dihydropyrimidines to 2-(alkylthio)pyrimidines using copper catalyst with no additives, such as an oxidant, acid, or base, has been developed. The reaction was successful with a wide range of 2-(alkylthio)-1,4-dihydropyrimidine substrates.     

Umsetzung von 3-(Dimethylamino)-2H-azirinen mit 1,3-Oxazolidin-2-thion zu 3-(2-Hydroxyethyl)-2-thiohydantoinen

Reaction of 3-(Dimethylamino)-2H-azirines with 1,3-Oxazolidine-2-thione to 3-(2-Hydroxyethyl)-2- thiohydantoins The reaction of 3-(dimethylamino)-2H-azirines 1 and 1,3-oxazolidine-2-thione ( 6 ), in MeCN at room temperature, yields, after hydrolytic workup, 3-(2-hydroxyethyl)-2-thiohydantoins 7 (Scheme 2). In the case of the spirocyclic 1c , crystallization of the crude reaction mixture leads to spiro [cyclopentane-1, 7′(7′aH)-imidazo [4, 3-b] oxazole] -5′-thione 8c . The mechanism is discussed.     

Some reactions of 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido) acetic acids

In situ generated 2,4-diaryl substituted münchnones from 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido)acetic acids react with acetic anhydride in the presence of 2-nitromethylene thiazolidine, which is most likely acting as a base, and unexpectedly undergo a Dakin–West type reaction and a concurrent autoxidation reaction leading to the formation of (E)-1-(N,4-dimethylbenzamido)-1-(4-fluorophenyl)prop-1-en-2-yl acetate, 4-substitutedphenyl-N-methyl-N-(4-substitutedbenzoyl) benzamides and p-substituted benzoic acids. In addition, a novel and efficient access to N-acyl urea derivatives is described by the reaction between 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido)acetic acids and cyclohexyl, isopropyl carbodiimides in the presence of a base. The structures of all new products were identified on the basis of NMR and IR spectra, along with X-ray diffraction data and HRMS measurements.     

One-Pot Synthesis of (E)-2-(3-Oxoindolin-2-ylidene)-2-arylacetonitriles

A highly efficient and expeditious one-pot approach towards 2-(3-oxoindolin-2-yl)acetonitriles was designed, which involves a base-assisted aldol reaction of ortho-nitroacetophenones, followed by hydrocyanation, triggering an unusual reductive cyclization reaction.     

Synthesis and properties of 1-(2-bromoethyl)-, 1-(2-alkoxyethyl)- and 1-(2-dialkylaminoethyl)2-alkylpyrroles

The reaction of 3-chloropropenyl alkyl ketones or 2,3-dichloropropyl alkyl ketones with 2-substituted ethylamine derivatives leads to the formation of the hitherto unknown 1-(2-R-ethyl)-2-alkylpyrroles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1047–1049, August, 1990.     

Synthesis of 2-(2-Naphthyl)quinolines from Z-3-(2-Naphthyl)-3-chloro-2-propenal

By reaction of Z-3-(2-naphthyl)-3-chloro-2-propenal and aromatic amines 1-(2-naphthyl)-3-iminoaryl-1-propenylarylamines were prepared which at heating in the glacial acetic acid afforded the corresponding 2-(2-naphthyl)quinolines.     

Stereoselective Syntheses and Biological Properties of (E)-α-(Methoxyimino)-2-[1-(aryloxy)methyl]-benzeneacetates

(E)-α-(Methoxyimino)-2-[1-(aryloxy)methyl]-benzeneacetates, the analogues of Kresoxim-methyl, were stereoselectively synthesized with the coupling reaction of 2-methylphenyldiazonium chloride and methyl 2-hydroxyiminoacetate in the presence of CuSO4/Na2SO3 as a key step, and it was first found that the coupling reaction could give the key intermediate material(E)- and(Z)-methyl 2-(hydroxyimino)-2-o-tolylacetate with a molar ratio of 14∶1. The(E)-configurations of all these compounds were assigned on the basis of their 2D-NOESY spectra of 1H NMR. The preliminary bioassays indicate that most of the compounds show an activity against a wide variety of fungi.     

Synthesis of (s)-2-(2-methylbutyl)thiophene

Optically active (S)-2-(2-methylbutyl)thiophene was obtained by different procedures. Among them, the cross-coupling reaction between 2-methylbutylmagnesium chloride and 2-chlorothio-phene proved to be the most efficient one. Compound 1 was thus obtained in satisfactory yield and rather high optical purity (82%).     

Total syntheses of beta-carboline alkaloids, (R)-(-)-pyridindolol K1, (R)-(-)-pyridindolol K2, and (R)-(-)-pyridindolol.

The total syntheses of beta-carboline alkaloids, (R)-(-)-pyridindolols (1, 5, and 6) are described. The two key steps involved are (1) a thermal electrocyclic reaction of the 3-alkenylindole-2-aldoxime 10 and (2) a thermal cyclization of 3-alkynylindole-2-aldoxime 11 to construct the beta-carboline N-oxides 8, which upon heating with acetic anhydride and sequential treatment with trifluoromethanesulfonic anhydride gave the triflates 18. The Stille coupling reaction of 18 with vinylstannane, followed by cleavage of MOM ether, afforded the 1-ethenyl-3-hydroxymethyl-beta-carboline (7a). Subsequent acetylation of 7a yielded the acetate 7b, which was subjected to the Sharpless asymmetric 1,2-dihydroxylation by AD-mix-beta to produce (R)-(-)-pyridindolol K2 (6). Selective acetylation of 6 was effected by Ac(2)O and collidine to form (R)-(-)-pyridindolol K1 (5). By contrast, hydrolysis of 6 provided (R)-(-)-pyridindolol (1).     

1-( p -Fluorophenyl)-2-(2′-pyridyl)ethanol and 1-( p -fluorophenyl)-2-(2′-pyridyl)ethene obtained from the condensation reaction of 2-picoline and p -fluorophenylaldehyde under catalyst-and solvent-free conditions

The novel intermediate 1-(p-fluorophenyl)-2-(2′-pyridyl)ethanol or 2-[2′-(1-hydroxy-1-(p-fluorophenyl)ethyl]pyridine and the corresponding novel dehydration compound 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene or 2-[p-fluorophenylvinyl]pyridine were obtained from the condensation reaction of p-fluorophenylaldehyde and 2-picoline under catalyst-and solvent-free conditions. The intermediate 1-(p-fluorophenyl)-2-(2′-pyridyl)ethanol was obtained at 42 h reaction time and temperature of 120°C, respectively. ¹H-NMR, IR spectroscopic data of the 1-(p-fluorophenyl)-2-(2-pyridyl)ethanol clearly showed the presence of the-CH₂-CHOH-group. The compound was obtained as a white powder with m.p. 121–122°C and a yield of 8%. For 1-(p-fluorophenyl)-2-(2-pyridyl)ethene, the reaction conditions were similar, but the reaction temperature was increased to yield the double bond in the 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene. At the reaction temperature of 140°C, the compound was a slightly brown powder with a m.p. of 78°C and yield of 18%. ¹H-NMR, IR spectroscopic data for the 1-(p-fluorophenyl)-2-(2′-pyridyl)ethene showed the presence of a double bond in trans configuration (-CH=CH-), characteristic of a styrylpyridine.     

Novel synthesis of 2-(trifluoromethyl)- and 2-(perfluoroalkyl)-2-hydroxy-2H-chromenes and their regiospecific reaction with silyl enol ethers

The synthesis of substituted 2-(trifluoromethyl)- and 2-(perfluoroalkyl)-2-hydroxy-2H-chromenes 2a-o was achieved in good yields by intramolecular cyclization of 3-(perfluoroalkyl)-3-phenoxypropenals 1 in the presence of aluminum chloride. Then a Lewis acid mediated nucleophilic reaction with silyl enol ethers 3 proceeded with complete regiospecificity to afford 4-functional 2-(trifluoromethyl)- and 2-(perfluoroalkyl)-4H-chromenes 4a-p with high yields.     

LDA-catalyzed cycloisomerization of 2-(2-propynyloxy)ethyl iodides leading to 3-(iodomethylene)tetrahydrofurans

LDA catalyzes cycloisomerization of 2-(2-propynyloxy)ethyl iodides to give 3-(iodomethylene)tetrahydrofurans. The reaction is proposed to proceed through a mechanism involving exo-cyclization of an alkynyllithium intermediate and protonation of the resulting alkylidene carbenoid by the starting iodide. [reaction: see text]     

Trialkylsilyl group-directed regioselective transformations of 2-(alk-1-yn-1-yl)-2-(trialkylsilyl)-1,3-dithianes to alkynylcyclopropanes and enynes

[reaction: see text] The Cp(2)Ti[P(OEt)(3)](2)-promoted reaction of 2-(alk-1-yn-1-yl)-2-(trialkylsilyl)-1,3-dithianes with 1-alkenes regioselectively produced [(trialkylsilyl)ethynyl]cyclopropanes with a formal allylic rearrangement. The reaction of the thioacetals with ketones proceeded with the same regioselectivity to produce 1-(trialkylsilyl)alk-3-en-1-ynes predominantly. It is suggested that these reactions proceed via the formation of titanium alpha-(silylethynyl)carbene complexes Cp(2)Ti=C(R)CCSi in preference to their regioisomers, alpha-silylalkynylcarbene complexes Cp(2)Ti=C(Si)CCR.     

An unusual reaction of 2-(2-pyridylcarbonyl)- and 2-(2-quinolylcarbonyl)benzoyl chlorides with p-nitroaniline

In the reaction of 2-(2-pyridylcarbonyl)benzoyl chloride, which exists in the form of 6,11-dioxo-6,11dihydrobenzo[b]quinolizinium chloride, with p-nitroaniline, 2-(4-nitrophenylimino)-6, 11-dihydro-2H-benzo-[b]quinolizine-6, I I -dione is unexpectedly formed. When it reacts with water or methanol there is an opening of the quinolizine ring and aromatization of the quinoid fragment with the formation of 2-[4-(4nitrophenylamino)-2-pyridylcarbonyl]benzoic acid or its methyl ester. Under the action of antimony pentachloride, 2- 2-quinolylcarbonyl)benzoylchloride-3 (2-quinolyl)-3-chloro- 1, 3-dihydrobenzo[c]furan-1 -one -is converted to 3-(2-quinolyl)-1,3-dihydrobenzo[c]furan-1-on-3-ylium hexachlorantimonate, which undergoes isomerizing recyclization upon heating to 7,12-dioxo-7,12-dihydrobenzo[b/ hexachloroantimonate. The latter enters into an analogous reaction with p-nitroaniline, thereby forming 5-(4-nitrophenylimino)-7,12-dihydro-5H-dibenzo[b,f]quinolizine-7,2-dione.Riga Technical University, Riga LV-1048. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 938–944, July, 1995. Original article submitted May 31, 1995.     

Synthesis and Alkylation of 4-(2-Chlorophenyl)-3-cyano-6-hydroxy-5-(2-thienoyl)-6-trifluoromethylpiperidin-2-thione

4-(2-Chlorophenyl)-3-cyano-6-hydroxy-5-(2-thienoyl)-6-trifluoromethylpiperidin-2-thione, which was used for the synthesis of 2-allylthio-4-(2-chlorophenyl)-3-cyano-6-hydroxy-5-(2-thienoyl)-6-trifluoromethyl-1,4,5,6-tetrahydropyridine, was obtained by the reaction of 2-thienoyltrifluoroacetone with 2-chlorophenylphenylmethylenecyanothioacetamide or with a mixture of 2-chlorobenzaldehyde and cyanothioacetamide in the presence of N-methylmorpholine. The molecular and crystal structure of the piperidinthione have been established by X-ray crystallography.     

苯乙烯基氮氧杂芳烃间的交叉光二聚反应

用中压汞灯(λ > 300 nm)照射4-苯乙烯基吡啶、2-苯乙烯基苯并噁唑和5-苯基-2-苯乙烯基噁唑三种杂芳基乙烯单体中任意两种的硫酸水溶液，得到三种交叉二聚体.用高效液相色谱跟踪研究了交叉光二聚反应，发现每组反应生成三种光二聚体，其中二种为单体自身的光二聚体，而另外一种是两种不同单体的交叉光二聚体.交叉二聚体通过柱色谱分离得到，其顺式头对尾结构经紫外、红外、氢谱、碳谱和元素分析确定.用紫外光谱和高效液相色谱跟踪研究了交叉光二聚体的稀溶液在低压汞灯（λmax=254 nm）照射下的光解反应.研究发现交叉二聚体能够彻底发生光解，首先生成原来的反式单体，所生成的反式单体容易发生异构化而生成顺式单体，最终建立起反顺异构化平衡.