Design,synthesis, and biological evaluation of novel substituted imidazo[2,1-a]isoindole derivatives as antibacterial agents

An efficient protocol has been developed for the synthesis of fused imidazo[2,1-a]isoindol-5-ones (2a–d) from 2-iodo benzoic acids and N,N-carbonyldiimidazole (CDI) using one-pot Pd-catalyzed C?C bond coupling. The reaction of imidazo[2,1-a]isoindol-5-one (2a–d) with substituted α-bromo ketones in toluene afforded corresponding imidazo[2,1-a]isoindolium derivatives (3a–i) in good yields. The structures of the title compounds were well established on the basis of infrared (IR), ¹H NMR, carbon-13 nuclear magnetic resonance (¹³C NMR), mass spectral data, and elemental analysis (C, H, and N). In vitro antibacterial results revealed that, the compounds 3b and 3i were found to possess an excellent broad spectrum of inhibiting potency against all the tested bacterial strains with minimum inhibitory concentration values ranging from 3.125 to 25?µg mL^?1.     

A new anthraquinone glycoside from Rhamnus nakaharai and anti-tyrosinase effect of 6-methoxysorigenin

In continual study on the heartwood of Rhamnus nakaharai, a new alaternin-8-O-glucoside, namely 1,2,6,8-tetrahydroxy-3-methylanthraquinone-8-O-β-glucopyranoside (1), together with some known compounds were further isolated and characterised by 1-D, 2-D NMR and other spectral evidences. The free radical scavenging and antityrosinase activities of the isolates, including alaternin (1a), emodin (2a), emodin-8-O-β-glucopyranoside (2), 6-methoxysorigenin-8-O-β-glucopyranoside (3) and 6-methoxysorigenin (3a) were tested. Alaternin (1a) exhibited to be mild DPPH radical scavenger with half as potent as vitamin C, while both alaternin (1a) and emodin-8-O-β-glucopyranoside (2) exhibited stronger SOD-like activity than that of BHA. 6-Methoxysorigenin (3a), a reported potential antioxidant, and its 8-O-glucoside (3) both performed significant inhibitory effect on mushroom tyrosinase with about twice as potent as kojic acid, the positive control.     

Novel Synthesis of a Macromonomer Having Organosilyl and Amino Groups

Abstract

Reaction between dimethyldivinylsilane (1) and N,N′-diethyl-N-lithio-ethylenediamine (2a) in the presence of N,N′-diethylethylenediamine (3a) in THF at 20°C gave a monoadduct, 3,3-dimethyl-6-ethyl-3-sila-6,9-diaza-1-undecene (4a). An anionic self-polyaddition reaction of 4a in the presence of lithium diisopropylamide (LDA) proceeded to form oligomers. Each of the oligomers thus obtained was found to carry a polymerizable vinylsilane moiety at the oligomer chain terminal. As a result, a new type of macromonomer having alternating repeating units of ethylenediamine and organosilyl groups was synthesized. Acid-base titration showed the macromonomer to have unique characteristics on protonation of diamine moieties. Anionic polyaddition reactions between 1 and N-lithio-piperazine (2b) in the presence of piperazine (3b) also gave a macromonomer consisting of alternating repeating units of piperazine and organosilyl groups (4b). Radical copolymerizations of styrene with 5b gave comblike graft copolymers.     

Halo-substituted (S)-N-(2-benzoylphenyl)-1-benzylpyrolidine-2-carboxamides as new chiral auxiliaries for the asymmetric synthesis of (S)-α-amino acids

The synthesis of new chiral auxiliaries (S)-N-(2-benzoylphenyl)-1-(3,4-dichlorobenzyl)-pyrrolidine-2-carboxamide (1a), (S)-N-(2-benzoylphenyl)-1-(pentafluorobenzyl)pyrrolidine-2-carboxamide (1b), and (S)-N-(2-benzoylphenyl)-1-(4-isopropoxytetrafluorobenzyl)pyrrolidine-2-carboxamide (1c) and their application in the asymmetric synthesis of amino acids using Ni^II complexes of their Schiff"s bases with alanine and glycine are described. Compound 1a is particularly appropriate for highly stereoselective synthesis of -methyl--amino acids with high enatiomeric purity (ee >95%).     

Reactions of 3-[N-chloroacetylamino-N-(4-nitrophenyl)]-2-formylindole with alkylamines

The reactions of 3-[N-chloracetylamino-N-(4-nitrophenyl)]-2-formylindole (1a) with 2-(N, N-dialkylamino)ethylamines afford complex condensation products 7b,c consisting of two similar but not identical diazepinoindole fragments. For the reaction of compound 1a with 3-(N,N-diethylamino)propylamine, the process occurs in a different manner, and the predominant product is 4-ethylaminopropyl-1-(4-nitrophenyl)-2-oxo-1,2,3,4,5,6-hexahydro[1,4]diazepino[6,5-b]indole hydrocloride (14). Two routes of these unexpected transformations were proposed. The structures of the synthesized products were proved by the ¹sH and ¹³C NMR, HMBC, and HSQC (direct proton-carbon correlation) spectra. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1536–1542, August, 2007.     

N-烷基/芳基-N'-(4-芳基噻唑-2-基)-N"-糖基胍的合成及生物活性研究

2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖基异硫氰酸酯(1)与2-氨基-4-取代苯基噻唑(2a～2b)反应, 生成糖基硫脲衍生物3a～3b, 再在伯胺存在下经氯化汞脱硫, 得到一系列新的N-烷基/芳基-N'-(4-芳基噻唑-2-基)-N"-糖基胍类化合物(4a～4e, 5a～5e). 所有新化合物的结构均经IR, ¹H NMR, MS谱和元素分析证实, 所得产物均为β-构型. 生物活性测试结果表明, 化合物4b和5d对HIV-1 PR表现出了较高的抑制活性.     

Synthesis of Fused Isolated Azoles and N-Heteroaryl Derivatives Based on 2-Methyl-3,4-dihydrothieno[3,4-d]pyrimidin-5-amine

In this work, we report the synthesis and characterization of new compounds derived from thieno[d]pyrimidines. The formation of isolated and fused thieno[d]pyrimidine derivatives was achieved via reacting 5-amino-(2-methyl)thieno[3,4-d]pyrimidin-4(3H)-one (3) with some selected reagents. The starting compound (2) was prepared in a quantitative yield using a modified procedure by conversion of the cyano group in 1 to the amide via hydrolysis using concentrated H₂SO₄. Methylthieno[3,4-d]pyrimidin-5-yl (8, 9, and 18), 3-phenylthieno[3,4-e][1,2,4]triazolo[4,3-c]pyrimidines (11–15) and tetrazolo[1,5-c]thieno[3,4-e]pyrimidine (16) have been synthesized in excellent isolated yield. The interaction of N-acetyl derivative 19 with benzaldehyde and/or some nitroso compounds afforded the chalcones and Schiff's bases derivatives 20 and 26a and c respectively. The latter compounds were used as key intermediates in the synthesis of N-acetylpyrazol-3-yl (21a and 21b), 6-phenylpyrimidine-2-(one)thione (22a and b), pyrazolo-1-carbothioamide (25), and thiazolidinone andβ β-lactam derivatives 28a and 28c and 30a and 30c respectively. The structures of these compounds were established by elemental analysis, infrared (IR), mass spectrometry (MS), and NMR spectral analysis.     

非对称双(均三唑席夫碱)衍生物的合成及抗肿瘤活性

为寻找新结构的水溶性抗癌先导化合物, 采用氨基均三唑硫代苯丙酮(1)与氨基均三唑硫醇(2a～2e)缩合得双均三唑单席夫碱化物3a～3e, 接着依次与氨基氯乙烷和水杨醛进行亲核取代和缩合反应, 分别得到含碱性侧链的单席夫碱4a～4e和非对称双席夫碱5a～5e. 所合成新化合物的结构经元素分析和光谱数据表征, 用甲基四噻唑蓝比色法(MTT)对新化合物进行了对于CHO, HL60和L1210 3种癌细胞株的体外活性试验. 在合成的15个新化合物中, 双席夫碱结构的抗癌活性最强, 其IC₅₀值在20.0 μmol•L^－1以下, 尤其是均三唑环连有双供电子取代基时(如化合物5c), 表现出潜在的活性, 其抗癌活性与上市药物比生群相当, 具有侯选药物研究的价值.     

One-pot synthesis of chromeno[2,3-b]isoindolo[1,2-e]pyrrole-12,13-dione derivatives by sequential reaction of ninhydrin, 2-aminochromen-4-ones and arylamines

Stirring an equimolar mixture of ninhydrin 1 and 2-aminochromen-4-ones 2 in CH₃COOH at room temperature produced 6a,11a-dihydroxy-6H-chromeno[2,3-b]indeno[2,1-d]pyrrole-11,12(6aH,11aH)-diones 3, which on heating with aromatic amines 6 in acetic acid produced 11b-hydroxy-7-N-arylimino-6H-chromeno[2,3-b]isoindolo[1,2-e]pyrrole-12,13(11bH)-diones 7.     

A new ceramide from the root of <Emphasis Type="Italic">Isatis Indigotica</Emphasis> and its cytotoxic activity

In addition to two ceramides 1-O-β-D-glucopyranosyl-(2S,3R)-N-(2'-hydroxyhexadecanoyl)-octadeca-4E,8Esphingenine (2) and (2S,3S,4R)-N-(2'-hydroxytetracosanoyl)-octadecasphingenine (3), which separated for the first time, a new ceramide 1-O-β-D-glucopyranosyl-(2S,3R)-N-(2'-hydroxyhexacosanoyl)octadecasphingenine (1) was isolated from the traditional Chinese medicinal herb Isatis indigotica. Their cytotoxic effects were evaluated by the MTT method.     

The synthesis of azahomotryptophane derivatives. The transformation of N-trifluoroacetyl-5-bromo-4-oxonorvaline methyl ester into 4-(imidazo[1,2-a]azinyl-3)-4-oxohomoalanine derivatives

Azatryptophane homologues, 4-(imidazo[1,2-a]pyridinyl-3)- 9a-9f and 4-(imidazo[1,2-a]pyrimidinyl-3)-4-oxohomoalanine derivatives 9g-91 , were prepared from N,N-dimethyl-N′-(pyridinyl-2)- 6a-6f and N,N-dimethyl-N-(pyriniidinyl-2)formamidines 6g-6i , and (S)-N-trifluoroacetyl-5-bromo-4-oxonorvaline methyl ester ( 2 ) and its (R,S)-isomer.     

New mesoionic systems of azolopyridine series 2. Synthesis,structures, and biological activity of 2-aminothiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]pyridinium salts and thiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]pyridinium 2-imidates

A new procedure was developed for the synthesis of 2-aminothiazolo[3,2-a]pyridinium salts 8 by the reaction of 2-halo-N-phenacylpyridinium salts with KSCN. The anion compositions of salts 8 were studied by ion chromatography. Acylation of salts 8 afforded representatives of the previously unknown bicyclic mesoionic thiazolo[3,2-a]pyridinium 2-imidate system 9. The three-dimensional structures of 2-amino-3-(p-bromobenzoyl)thiazolo[3,2-a]pyridinium thiocyanate and N-trifluoroacetyl-3-(p-nitrobenzoyl)thiazolo[3,2-a]pyridinium 2-imidate were established by X-ray diffraction analysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 226–232, January, 2005.     

Synthesis and structural characterization of ruthenium complexes with 1-aryl-imidazole-2-thione

Treatment of [RuCl₂(PPh₃)₃] with 2 equiv. Himt^MPh (Himt^MPh?=?1-(4-methyl-phenyl)-imidazole-2-thione) in the presence of MeONa afforded cis-[Ru(κ ²-S,N-imt^MPh)₂(PPh₃)₂] (1), while interaction of [RuCl₂(PPh₃)₃] and 2 equiv. Himt^MPh in tetrahydrofuran (THF) without base gave [RuCl₂(κ ¹-S-Himt^MPh)₂(PPh₃)₂] (2). Treatment of [RuHCl(CO)(PPh₃)₃] with 1 equiv. Himt^MPh in THF gave [RuHCl(κ ¹-S-Himt^MPh)(CO)(PPh₃)₂] (3), whereas reaction of [RuHCl(CO)(PPh₃)₃] with 1 equiv. of the deprotonated [imt^MPh]^? or [imt^NPh]^? (imt^NPh?=?1-(4-nitro-phenyl)-2-mercaptoimidazolyl) gave [RuH(κ ²-S,N-imt^RPh)(CO)(PPh₃)₂] (R?=?M 4a, R?=?N 4b). The ruthenium hydride complexes 4a and 4b easily convert to their corresponding ruthenium chloride complexes [RuCl(κ ²-S,N-imt^MPh)(CO)(PPh₃)₂] (5a) and [RuCl(κ ²-S,N-imt^NPh)(CO)(PPh₃)₂] (5b), respectively, in refluxing CHCl₃ by chloride substitution of the RuH. Photolysis of 5a in CHCl₃ at room temperature afforded an oxidized product [RuCl₂(κ ²-S,N-imt^MPh)(PPh₃)₂] (6). Reaction of 6 with excess [imt^MPh]^? afforded 1. The molecular structures of 1·EtOH, 3·C₆H₁₄, 4b·0.25CH₃COCH₃, and 6·2CH₂Cl₂ have been determined by single-crystal X-ray crystallography.     

2-甲硫基-7(5)-取代-3-吡唑并[1,5-a]嘧啶甲酸乙酯的区域选择性合成与2D NMR 研究

利用3-甲硫基-4-乙氧羰基-5-氨基-1H-吡唑分别与甲基/芳基烯胺酮反应, 合成了8种新的化合物2-甲硫基-7-取代-3-吡唑并[1,5-a]嘧啶甲酸乙酯(3a～3g)和2-甲硫基-5-甲基-3-吡唑并[1,5-a]嘧啶甲酸乙酯(4a). 化合物的结构均经元素分析, IR, ¹H NMR, MS所证实, 异构体3a和4a的结构进一步由¹³C NMR, HMQC和HMBC确认. 同时, 探讨了区域选择性合成吡唑并[1,5-a]嘧啶类化合物可能的反应机理, 并对部分化合物杀菌活性进行了测试.     

Expeditious Synthesis of a Trisubstrate Analogue for α(1→3)Fucosyltransferase

Abstract

The synthesis of cyclohexyl 2-acetamido-2-deoxy-3-O-{2-O-[2-(guanosine 5′-O-phosphate)ethyl]-α-L-fucopyranosyl}-β-D-glucopyranoside (1), a potential inhibitor of α(1→3)fucosyltransferases, is described. Target compound 1 was assembled via fucosylation of cyclohexyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-β-D-glucopyranoside (6) with ethyl 2-O-[2-(benzoylhydroxy)ethyl]-3,4-O-isopropylidene-1-thio-β-L-fucopyranoside (5) followed by debenzoylation, subsequent condensation of the resulting compound with 3′,4′ -di-O-benzoyl-5′ -O-(2-cyanoethyl-N,N-diisopropylphosphoramidite)-2-N-diphenylacetylguanosine (10) and deprotection.     

A new phenylimidorhenium(V) compound containing the 2-[(2-hydroxyethylimino)methyl]phenol Schiff-base ligand: experimental and theoretical aspects

Reaction of equimolar trans-[Re(NPh)(PPh₃)₂Cl₃] with H₂L, a 1?:?1 Schiff-base condensate of salicylaldehyde and ethanolamine, in chloroform gives trans-[Re(NPh)(HL)(PPh₃)Cl₂] (1a) in good yield. 1a has been characterized by C, H, and N microanalyses, FTIR and UV–vis spectra. The X-ray crystal structure of 1a reveals that it is an octahedral trans-Cl,Cl phenylimidorhenium(V) complex. The rhenium center has an ‘N₂OCl₂P’ coordination sphere. 1a crystallizes in the monoclinic space group P2₁/c with a = 11.2391(5), b = 16.4848(7), c = 16.3761(8) Å, V = 3034.0(2) ų and Z = 4. The electrochemical aspects of 1a have been studied. Electrochemical studies of 1a in dichloromethane show a quasi-reversible Re(V) to Re(VI) oxidation at 1.128 V versus Ag/AgCl. This redox potential reasonably matches the calculated redox potential, 1.186 V versus Ag/AgCl. Geometry optimization of the trans-Cl,Cl 1a vis-à-vis its cis analog, cis-Cl,Cl 1b, have been performed at the level of density functional theory (DFT). It is revealed that 1a is more stable than 1b by 21.6 kcal per mole of energy in the gas phase.     

(S)-(+)-N-取代吡咯烷甲醇衍生物的合成及晶体结构

从L-α-脯氨酸出发,经过酯化、N-烷基化、与格氏试剂反应合成了6个未见文献报道的(S)-(+)-N-取代吡咯烷甲醇衍生物3a～3f,其结构经IR,1HNMR和元素分析测定确证.并用X射线单晶衍射法测定了化合物(S)-(+)-1-[N-(5-氯-2-噻唑甲基)-2-吡咯烷基]-1,1-二苯基甲醇(3e)的晶体结构.晶体为单斜晶系,空间群为P2(1),a=0.8737(14)nm,b=0.9098(14)nm,c=1.2180(17)nm,α=90.00°,β=92.55(3)°,γ=90.00°,V=0.9671(3)nm3,Z=2,Dc=1.3217g/cm3,F(000)=404,R=0.0584,wR=0.1335.     

2-[3-(Trifluoromethyl)phenyl]furo[3,2-b]pyrroles: synthesis and reactions

The synthesis and reactions of methyl 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole-5-carboxylate (1a) are described. Upon reaction with methyl iodide, benzyl chloride, or acetic anhydride, this compound gave N-substituted products 1b-d. By hydrolysis of compounds 1a-c, the corresponding acids 2a-c were formed, or by reaction with hydrazine-hydrate, the corresponding carbohydrazides 3a-c were formed. By heating 2-[3-(trifluoromethyl)phenly]-4H-furo[3,2-b]pyrrole-5-carboxylic acid (2a) in acetic anhydride, 4-acetyl-2-[3-(trifluoromethyl)phenyl]furo[3,2-b]pyrrole (4) was formed. By hydrolysis of 4, 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole (5a) was formed, and reactions with methyl iodide or benzyl chloride gave N-substituted products 5b-c. The reaction of 4 with dimethyl butynedioate gave substituted benzo[b]furan 6. Compound 3a reacted with triethyl orthoesters giving 7a-c, which afforded with phosphorus (V) sulphide the corresponding thiones 8a-c. The thiones 8a-c reacted with hydrazine hydrate to form hydrazine derivatives 9a-c. The reaction of triethyl orthoformiate with compounds 9a-c led to furo[2′,3′: 4,5]pyrrolo[1,2-d][1,2,4]triazolo[3,4-f][1,2,4]triazines 10a-c. Hydrazones 11a-c were formed from 3a-c and 5-[3-(trifluoromethyl)phenyl]furan-2-carboxaldehyde. The effect of microwave irradiation on some condensation reactions was compared with “classical” conditions. The results showed that microwave irradiation shortens the reaction time while affording comparable yields.     

Synthese von 1-Ary1-4-methylthio-2-azetidinonen

TheN-arylthioformimidates4 a-e, which may be obtained byS-alkylation of the thioformanilides3 a-e, react with chloroacetylchloride/triethylamine to yield the (3R,4S/3S,4R)-1-aryl-3-chloro-4-methylthio-2-azetidinones5 a-e and the formanilides6 a-e. Dehalogenation of5 b-e with tri-n-butyltinhydride yield the title compounds7 b-e. Hydrogenolysis of7 b and7 c yields7 f and7 g.

     

Catalytic Enantioselective Reactions Part 7. Synthesis of New β-Aminoalcohols Derived from α-D-Glucose as Chiral Catalysts for the Catalytic Enantioselective Addition of Diethylzinc to Aldehydes

A series of new 1, 2-O-isopropylidene-3-O-methyl-6-deoxy-6-N, N-dialkylamino-α-D-glucofuranoses 1 and 1, 2-O-isopropylidene-3, 6-dideoxy-6-N, N-dialkylamino-α-D-glucofuranoses 1′ were prepared from α-D-glucose and their enantiose-lectivities compared as chiral catalysts for the ethylation of benzaldehyde and heptanal with diethylzinc.