Synthesis of dimethyl 3-perfluoroalkyl-4-(3-oxo-2-triphenyl-phosphoranylidenbutanylidene)-pent-2-enedioate and its cyclization

The title compounds 5a-5c were prepared via the reaction of methyl 2-perfluoroal-kynoates (4) with methyl 5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate (3), which was obtained from the reaction of methyl propynate (2) with acetylmethylenetriphenylphosphorane (1) at -5-0℃. Intramolecular elimination of Ph3PO took place when compound 5 was heated in aqueous methanol at 115-120℃ in sealed tube, yielding dimethyl 2-trifluoromethyl-4-methylisophthalate (6a) from 5a and methyl 5-acetyl-4-hydroxy-2-heptafluoropropanylbenzoate (6b) from 5b, respectively. The structures of compounds 5, 6a and 6b were confirmed by IR, MS, 1H NMR, 19F NMR and 13C NMR spectroscopy and elemental analyses. Rection mechanisms for the formation of compounds 5, 6a and 6b were proposed.     

Silica Gel Catalyzed Conversion of Dimethyl 2-(5-Bromo-2-hydroxyphenyl)-3-(triphenylphosphoranylidene)butanedioate to Methyl 6-Bromo-2-oxo-2H-chromene-4-carboxylate in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate, by 4-bromophenol leads to vinyltriphenylphosphonium salt, which undergoes aromatic electrophilic substitution reaction with conjugate base to produce dimethyl 2-(5-bromo-2-hydroxyphenyl)-3-(triphenylphosphoranylidene)butanedioate. Silica gel was found to catalyze conversion of dimethyl 2-(5-bromo-2-hydroxyphenyl)-3-(triphenylphosphoranylidene)butanedioate to methyl 6-bromo-2-oxo-2H-chromene-4-carboxylate in solvent-free conditions at 80°C in fairly high yield.     

Heterocyclisation of substituted ylidenethiocarbonohydrazides using dimethyl acetylenedicarboxylate

A facile and rapid procedure for the synthesis of dimethyl-2-[3-amino-5-(2-methoxy-2-oxoethylidene)-4-oxothiazolidin-2-ylidenehydrazono]succinate, dimethyl {[2-alkylidenehydrazono)-5-(2-methoxy-2-oxoethylidene)-4-oxothiazolidin-3-yl)amino]succinate and methyl (4-amino-5-oxo-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazine-6-yl)acetate affording yields of 61–54 %, 22–18 % and 14–11 %, respectively, via a condensation reaction of dimethyl acetylenedicarboxylate (DMAD) with (substituted ylidene)thiocarbonohydrazides. One of the products was conclusively confirmed by single-crystal X-ray analysis. A mechanism for the formation of the products is presented.     

新型苯并二氢呋喃合二酮酸类化合物的合成及其与整合酶分子对接研究

以阿魏酸甲酯为原料,通过氧化偶联构建2-芳基苯并二氢呋喃骨架,再经傅克酰基化和酯缩合反应依次制得(E)-3-［2-(4-羟基-3-甲氧基-5-乙酰基)苯基-3-甲氧羰基-7-甲氧基-2,3-二氢苯［b］并呋喃-5-基］丙烯酸甲酯（3）和(E)-3-［2-(4-羟基-3-甲氧基-5-甲氧羰基乙酰基)苯基-3-甲氧羰基-7-甲氧基-2,3二氢苯并［b］呋喃-5-基］丙烯酸甲酯（4）; 4经水解反应合成3-【2-羟基-3-甲氧基-5-｛5-［2-（甲氧基羰基）乙烯基］-7-甲氧基-3-甲氧羰基-2,3-二氢苯并［b］呋喃-2-｝基】苯基-3-氧丙酸（5）,化合物3~5未见文献报道,其结构经¹H NMR, ¹³C NMR和MS(ESI)表征。采用分子对接软件Autodock vina对化合物2~5与HIV-1整合酶核心部位高度同源的PFV IN（PDB: 3L2V）进行对接,计算结果显示该类化合物能与整合酶形成稳定的复合物,具有1,3-二酮基团的化合物3, 4和5能与整合酶中金属离子产生螯合作用,其中化合物5的结合作用最强。     

Investigation of nitrogen- and sulfur-containing heterocycles

The reaction of 5-amino-4-chloro- and -4-methoxy-6~mercaptopyrimidines with 4-methoxy-, 4-amino-, and 2,4-diethoxyphenacyl chlorides has yielded 5-amino-4-chloro- and -4-methoxy-6-phenacylthiopyrimidines. The reaction of 2, 5-diamino-4-methyl-6-mercaptopyrimidine with 4-methoxyphenacyl chloride has yielded 2-amino-6-hydroxy-6-(4-methoxyphenyl)-4-methyl-5, 6-dihydropyrimido[4, 5-b]-1,4-thiazine, and that with 4-aminophenacyl chloride has yielded the corresponding 7H-pyrimido[4, 5-b]-1,4-thiazine.For part IV, see [1].     

Efficient synthesis of 6-aryl-4-trifluoromethyl/ethoxycarbonyl-2H-pyran-2-ones through self-condensation of penta-2,4-dienenitriles

An efficient synthesis of two new series of 6-aryl-4-trifluoromethyl-2H-pyran-2-ones and 6-aryl-4-carboxyethyl-2H-pyran-2-ones, obtained through the self-condensation reaction of 5-aryl-5-methoxy-3-(trifluoromethyl)penta-2,4-dienenitriles 3 and ethyl 4-aryl-2-(cyanomethylene)-4-methoxybut-3-enoates 4 respectively, is reported. The self-condensation reaction of the enoates 4 was performed in water in the presence of hydrochloric acid whereas the self-condensation reaction of the penta-2,4-dienenitriles 3 required the use of zinc bromide and hydrochloric acid in order to give the respective 2H-pyran-2-ones. Products were obtained up to 97% yield.     

Reaction of 3,4,6-trioxoalkanoic acid esters with 2,4-dinitrophenylhydrazine

Methyl 3,4,6-trioxoalkanoates (3,4-dihydroxy-6-oxo-2,4-alkadienoates) reacted with 2,4-dinitrophenylhydrazine to give methyl 3,6-bis[(2,4-dinitrophenyl)hydrazinylidene]-4-oxoalkanoates or methyl {5-alkyl-2-hydroxy-1-(2,4-dinitroanilino)-3-oxo-2,3-dihydro-1H-pyrrol-2-yl }acetates. Alkyl 3,6-bis[(2,4-dinitrophenyl) hydrazinylidene]-4-oxoalkanoates were also synthesized by reaction of disodium 1-alkoxy-1,6-dioxoalka-2,4-diene-3,4-diolates with 2,4-dinitrophenylhydrazine.     

Condensations of γ-Acetylacetonephosphonium Ylide (1-(Triphenylphosphoranylidene) pentane-2,4-dione) with Carbonyl Compounds

2,4-Dioxopentyltriphenylphosphonium bromide reacted with aqueous sodium hydrogencarbonate in dichloromethane to give, in almost quantitative yield, 1-(triphenylphosphoranylidene) pentane-2,4-dione. Dianion Wittig- and Michael Wittig condensations of the last mentioned phosphonium ylide with carbonyl compounds gave unsaturated 2,4-diketones which were almost totally enolised in deutero chloroform as 4-hydroxy-2-oxo-3,5-dienes (24–70% yields). These products closely resembled the type of compounds derived from similar condensations with alkyl 3-oxo-4-(triphenylphosphoranylidene)butanoate.     

Imidotungsten(VI) complexes with chelating amino and imino phenolates

The reaction of WOCl(4) with 2,4-di-tert-butyl-6-((isopropylamino)methyl)phenol followed by the reaction with phenyl isocyanate leads to the formation of imidotungsten(VI) complex [W(NPh)Cl(3)(OC(6)H(3)(CH(2)NH-i-Pr)-2-t-Bu(2)-4,6)] 4 with a chelating aminophenolate ligand. When the same procedure was applied using aminophenols with bulkier substituents in the amino group, the final product was an unexpected Schiff-base complex [W(NPh)Cl(3)(OC(6)H(3)(CH=NPh)-2-t-Bu(2)-4,6)] 5, where the ligand is derived from 2,4-di-tert-butyl-6-((phenylimino)methyl)phenol. Complex 5 is also formed in the thermal degradation of 4. On the whole, 5 appears to be formed by a disproportionation of intermediate compounds, which are analogous to complex 4. The solid-state structures of 4 and 5 have been determined by X-ray crystallography whereas the solution structures were studied by (1)H and (13)C NMR.     

Reaction of aromatic aldehydes with β-dicarbonyl compounds in a catalytic system: Piperidinium acetate-1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

Condensation of aromatic (heteroaromatic) aldehydes with 1,3-dicarbonyl compounds under the 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF₄]) ionic liquid-piperidinium acetate catalytic system (0.2 equiv. of each component) in the absence of a solvent affords, depending on the structures of the reagents, 2-arylidene derivatives of methyl acetoacetate and acetylacetone, diethyl 2,4-bis(trifluoroacetyl)-3-phenylpentanedioate, or dimethyl 2-aryl-4-hydroxy-6-oxocyclohexane-1,3-dicarboxylates. The reactions of the resulting 2-arylidene derivatives with O-methylisourea in the [Bmim][BF₄] ionic liquid produced methyl 2-methoxy-4-methyl-6-aryldihydropyrimidine-5-carboxylates and 1-(2-methoxy-4-methyl-6-phenyldihydropyrimidin-5-yl)ethanone (mixtures of 3,6- and 1,6-dihydro isomers), which were transformed into the corresponding 3,4-dihydropyrimidin-2(1H)-one derivatives. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1199–1204, May, 2005.     

Antifungal agent and other constituents from Cynanchum otophyllum

Seven constituents were isolated from the ethyl acetate extract of the rhizome of Cynanchum otophyllum Schneid (Asclepiadaceae). Their structures were determined as 1-(4-methoxy-3-(6-methoxy-3-acetylphenylperoxy)phenyl)ethanone (1), 1-(3-hydroxy-7-acetylnaphthalen-2-yl)ethanone (2), 1-(3,4-dihydroxyphenyl)ethanone (3), 1-(2,4-dihydroxyphenyl)ethanone (4), 1-(3-(3,6-dihydroxy-2-methylbenzoyl)-2,4-dihydroxyphenyl)ethanone (beishouwubenzophenone) (5), N,N-dimethylethanamine (6), and 2-oxo-2-phenylacetic acid (7), respectively, by spectral methods. Among them, 1 and 2 were new compounds; 1 had antifungal activity.     

An efficient synthesis of 5-bromo-2-methoxy-6-methylaminopyridine-3carboxylic acid

An efficient synthesis of 5-bromo-2-methoxy-6-methylaminopyridine-3-carboxylic acid (1), a carboxylic acid moiety of a potent dopamine D2 and D3 and serotonin-3 (5-HT3) receptors antagonist, (R)-5-bromo-N-(1-ethyl-4-methylhexahydro-1 ,4-diazepin-6-yl)-2-methoxy-6-methylaminopyridine-3-carboxamide, is described. Reaction of methyl 2,6-difluoropyridine-3-carboxylate (12) with methylamine in EtOH at -25 degrees C gave a mixture of methyl 2-fluoro-6-methylaminopyridine-3-carboxylate (13) and the regioisomer 14 in a ratio of 57 : 43. On the other hand, reaction of 12 and methyl 2,6-dichloropyridine-3-carboxylate (16) with sodium methoxide in tetrahydrofuran (THF) and CH2Cl2 provided the 2-methoxypyridine-3-carboxylic esters 20 and 23, respectively, as main products. Similar reaction of 16 in N,N-dimethylformamide (DMF) and MeOH proved to be highly regioselective for the 6-position. A much greater regioselectivity for substitution at the 6-position (>97%) was observed when 16 was treated with 4-methylbenzenethiolate anion in DMF (quantitative yield). After methoxylation of methyl 2-chloro-6-(4-methylbenzenethio)pyridine-3-carboxylate (25b) and successive oxidation of the 6-benzenethio moiety, nucleophilic substitution of the sulfoxide derivative 28 with methylamine gave the 6-methylamino derivative 8. Finally, bromination of 8 and alkaline hydrolysis produced the desired product 1 in an overall yield of 67%.     

Reactions of Polyfluorinated 3-Substituted 2,4-Cyclohexadienones with Alkynes

Reactions of 2,3,4,5,6-pentafluoro-6-chloro-2,4-cyclohexadienone with anthranylic acid, 2,6-dichloro- and 2,6-dimethylaniline, diethylamine, sodium azide, and also the reaction of 6-phenyl-3-pentafluorophenoxy-2,4,5,6-tetrafluoro-2,4-cyclohexadienone with methanol afford 3-substituted 2,4,5,6-tetrafluoro-2,4-cyclohexadienones. The 3-methoxy-2,4,5,6-tetrafluoro-6-chloro-2,4-cyclohexadienone and 3-methoxy-6-phenyl-2,4,5,6-tetrafluoro-2,4-cyclohexadienone form cycloadducts with 1-hexyne and propargyl alcohol that under treatment with propyl alcohol in the presence of potassium carbonate undergo ring cleavage to furnish propyl arylfluorochloroacetates and diarylacetates. The reaction between 3-azido-2,4,5,6-tetrafluoro-6-chloro-2,4-cyclohexadienone and phenylacetylene gives rise to 4-oxo-2-phenyl-3,5,6,7-tetrafluoro-5-chlorobicyclo[4.1.0]hept-2-ene-7-carbonitrile.     

Aza-Morita-Baylis-Hillman reactions and cyclizations of conjugated dienes activated by sulfone, ester, and keto groups

The aza-Morita-Baylis-Hillman reactions of aldimines 2 with several activated conjugated dienes were found to proceed smoothly in DMF in the presence of 3-hydroxyquinuclidine (HQD). Imines 2 reacted with 1-(p-toluenesulfonyl)-1,3-butadiene (3), methyl 2,4-pentadienoate (6), hexa-3,5-dien-2-one (7), and 1-phenylpenta-2,4-dien-1-one (8) to afford adducts 4, 13, 14, and 15, respectively. While products 4, 13, and 15 were formed as E,Z mixtures, adducts 14 were obtained as essentially pure E-isomers. Cyclization of the E-isomers of the products derived from the dienyl sulfone 3 and the dienoate ester 6 occurred via intramolecular conjugate addition under base-catalyzed conditions to afford functionalized piperidines 5 and 16, respectively. The aza-Morita-Baylis-Hillman reaction and subsequent cyclization of the imine 2a with 3 were also carried out as a one-pot reaction, while the reaction mixture was simultaneously irradiated at 300 nm to effect the photoisomerization of the unreactive Z-adduct of the corresponding 4 to the more reactive E-isomer.     

一种新型α-甲醚基吡咯的合成

以乙酰乙酸苄酯(4)为原料, 经Knorr缩合制备了2,4-二甲基-3-丙酸甲酯基-5-羧酸苄酯基-1-氢吡咯 (2) 和2,4-二甲基-3-羧酸甲酯基-5-羧酸苄酯基-1-氢吡咯(3)。乙醚介质中,溴水氧化条件下,吡咯 (2) 发生自身缩合生成二吡咯甲烷 (7),吡咯 (3)无反应发生。在Pb(OAC)₄氧化条件下,当其浓度为吡咯 (3)浓度的2倍时,在80 ℃,吡咯 (3) 完全转华。所得产物经HCl甲醇溶液回流,以82%的产率制备了新型2-甲氧基甲基-3-羧酸甲酯基-4-甲基-5-羧酸苄酯基-1氢吡咯 (1)。吡咯(1)、(2)、(3)及二吡咯(7)的结构用核磁、元素分析、质谱和红外等测试技术进行了表征。吡咯(1)的构建对进一步研究吡咯构效关系具有一定参考价值。     

Mesoionic dimethyl derivatives of some 1,2,4-triazinones. The course of the reaction of 3,5-dimethoxy, 3-methoxy-5-methylthio, 5-methoxy-3- methylthio and 3,5-bis(methylthio)-1,2,4-triazine with methyl iodide

Treatment of 3,5-dimethoxy-1,2,4-triazine ( 1a ) with methyl iodide was found to give depending on the reaction time triazinium iodide 2a , triaziniumolates 4a and 6a as well as methoxytriazinones 7a and 8a . Thermolysis of 2a gave triaziniumolates 4a and 6a . Reaction of 2a , 4a or methoxytriazinone 9a with methyl iodide in acetonitrile yielded as the sole product 6a . Reaction of 3-methoxy-5-methylthio-1,2,4-tri-azine (1b ) with methyl iodide gave triazinium iodide 2b and methylthio triazinone 7b . Hydrolysis of 2a,b afforded 4a . Reaction of 5-methoxy-3-methylthio-1,2,4-triazine ( 1c ) with methyl iodide gave triazinium iodide 2c , triaziniumolate 4b , triazinium iodide 5b and triazinone 8b . Hydrolysis of 2c yielded 4b and its thermolysis gave a mixture of 4b and 5b . Reaction of 2c , 4b and triazinone 9b with methyl iodide afforded 5b . Treatment of 3,5-bis(methylthio)-1,2,4-triazine ( 1d ) with methyl iodide was found to give a mixture of N1 and N2 methiodides 2d and 3d which gave on hydrolysis 4b and 8b , respectively. Methylation of 6-methyl derivatives 1c-g gave analogous results, however the proportions of N1 methylated products were lower and the reaction rates higher in comparison to their respective lower homologues 1a,c,d . The structures of the mesoionic dimethyl derivatives were assigned from uv, ir, ¹H nmr and electron impact mass spectra. The structural assignments were eventually confirmed by quantum chemical calculations of net charge distributions, bond lengths and ipso angles of the C5?O bonds.     

Codonocarpus alkaloids—IV : Synthesis of 2-methoxy-2′-ethoxy-4-[2-(tetramethylenecarbamoyl)ethyl]-5′-[2-(propylcarbamoyl)ethyl]diphenyl ether

Synthesis of the title compound was accomplished by coupling the iodonium bromide (3) of 4-ethoxybenzaldehyde with methyl hydroferulate (4) to 2-methoxy-2′-ethoxy-4-(methyl β-propionate)-5′-formyldiphenyl ether (5) which was converted to the pyrrolidinyl amide 6, and then the aryl aldehyde group was extended to a n-propyl β-propionamide unit via the Knoevenagel malonic acid reaction through the trans-cinnamic acid 7 followed by hydrogenation and amide formation with n-propylamine.     

Fortuneanosides G-L, dibenzofuran glycosides from the fruit of Pyracantha fortuneana

Six new dibenzofuran glycosides, fortuneanosides G (1), H (2), I (3), J (4), K (5), and L (6), were isolated from the fruit of Pyracantha fortuneana (MAXIM) LI. Their structures were determined to be 3,7-dihydroxy-2,4-dimethoxy-dibenzofuran 7-O-beta-D-glucopyranoside, 3,7-dihydroxy-2,4-dimethoxy-dibenzofuran 7-O-(alpha-L-rhamnopyranosyl)-(1-6)-beta-D-glucopyranoside, 3,6-dihydroxy-2,4-dimethoxy-dibenzofuran 6-O-beta-D-glucopyranoside, 2,4-dimethoxy-3,6,9-trihydroxy-dibenzofuran 6-O-beta-D-glucopyranoside, 3,9-dihydroxy-2,4-dimethoxy-dibenzofuran 3-O-beta-D-glucopyranoside, and 2-methoxy-3,4,9-trihydroxy-dibenzofuran 4-O-beta-D-glucopyranoside based on spectroscopic analysis. Fortuneanosides G-J showed more potent tyrosinase-inhibitory activity than arbutin.     

一类新型嘧啶苯氧(硫)醚的合成及生物活性

一类新型嘧啶苯氧(硫)醚的合成及生物活性;双乙烯酮; 氯硝基嘧啶; 苯氧（硫）醚; 嘧啶肼; 生物活性