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1.
María E. Monge Sergio M. Bonesi Rosa Erra‐Balsells 《Journal of heterocyclic chemistry》2002,39(5):933-941
Iododerivatives of N‐methylcarbazole ( 1 ), N‐phenylcarbazole ( 2 ), N‐benzylcarbazole ( 3 ), 2‐methoxy‐N‐methylcarbazole ( 4 ) and 3‐acetamido‐N‐ethylcarbazole ( 5 ) are synthesised. N‐Iodosuccinimide (NIS) in tetrahydrofurane/H2SO4 (catalyst), a mixture of KIO3 ‐ KI ‐ H2SO4 (catalyst) in ethanol and a mixture of KIO3 ‐ KI in glacial AcOH as iodinating agents have been used and their uses have been compared. The preparation, isolation and characterization of compounds 1a, 1b, 1c, 1d, 2a, 2b, 3a, 3b, 4a, 4b, 4c and 5a are reported (mp, tR, Rf, 1H‐nmr, 13C‐nmr, IR and ms). All of them are described for the first time except 3,6‐diiodo‐N‐phenyl‐carbazole ( 2b ). Semiempirical PM3 calculations have been performed to predict reactivity of N‐substituted carbazoles and their iododerivatives. Theoretical and experimental results are discussed briefly. 相似文献
2.
Sergio M. Bonesi Maria A. Ponce Rosa Erra‐Balsells 《Journal of heterocyclic chemistry》2004,41(2):161-171
1H and 13C nmr spectra of several N‐ and C‐substituted carbazoles (Series 1, 2, 3 and 4) were measured. Correlations between chemical shifts and substituent constants show that these parameters describe properly the substituent effect on the nmr phenomena. Atomic charge densities for carbazoles of Series 1, 2, 3 and 4 were calculated by using the semi empirical PM3 method. These values also show a linear correlation with the 13C chemical shifts. The synthesis of several carbazole derivatives 1a – 1g, 2a – 2g, 3a – 3j and 4a – 4g have been carried out according to literature procedures. The carbazoles 3i, 3j and 4c have been synthesized and fully characterized for the first time. 相似文献
3.
β‐Carbolines ( 1–5 ) undergo electrophilic aromatic substitution with N‐bromosuccinimide under different experimental conditions. Although 6‐bromo‐nor‐harmane ( la ) obtained by bromination of nor‐harmane ( 1 ) was isolated and fully characterized sometime ago, the other bromoderivatives of nor‐harmane ( 1b‐1e ) and harmane ( 2a‐2e ) were partially described as part of the reaction mixtures. The preparation and subsequent isolation, purification and full characterization of 1b, 1c, 1d, 1e, 2a, 2b, 2c, 2d, 2e are reported (mp, R f, 1H‐nmr, 13C‐nmr and ms) together with the preparation, isolation and charaterization, for the first time, of the bromoderivatives obtained from harmine ( 3a‐3e ), harmol ( 4a, 4b ) and 7‐acetylharmol ( 5a‐5c ). As brominating reagent N‐bromosuccinimide and N‐bromosuccinimide‐silica gel in dichloromethane and in chloroform as well as the β‐carboline ‐ N‐bomosuccinimide solid mixture have been used and their uses have been compared. Semiempirical AMI and PM3 calculations have been performed in order to predict reactivity in terms of the energies of HOMO, HOMO‐LUMO difference and in terms of the charge density of β‐carbolines ( 1–5 ) and bromo‐β‐carbolines ( 1a‐1e, 2a‐2e, 3a‐3e, 4a, 4b, 5a, 5b and 5c ) (Scheme 1). Theoretical and experimental results are discussed briefly. 相似文献
4.
MaríaB. Ponce FrancoM. Cabrerizo SergioM. Bonesi Rosa Erra‐Balsells 《Helvetica chimica acta》2006,89(6):1123-1139
The preparation, isolation and characterization by elemental analysis and 1H‐NMR, 13C‐NMR, and MS data of the bromo derivatives of N‐substituted carbazoles, i.e., of 9‐methyl‐9H‐carbazole ( 1 ), 9‐phenyl‐9H‐carbazole ( 2 ), 9‐benzyl‐9H‐carbazole ( 3 ), 2‐methoxy‐9‐methyl‐9H‐carbazole ( 4 ), and of C‐substituted carbazoles, i.e., of 2‐(acetyloxy)‐9H‐carbazole ( 5 ) and 3‐nitro‐9H‐carbazole ( 6 ), are reported, in part for the first time. As brominating reagents, N‐bromosuccinimide (NBS) or NBS/silica gel in CH2Cl2, NBS in AcOH, KBrO3/KBr in EtOH doped with a catalytic amount of H2SO4, or KBrO3/KBr in AcOH were employed, and their uses were compared. Semi‐empirical PM3 calculations were performed to predict the reactivity of the N‐substituted and C‐substituted carbazoles and of their bromo derivatives and found to verify the experimental results. The UV‐absorption and fluorescence and phosphorescence emission spectra of the bromocarbazole derivatives in MeCN solution at 298 K and in a solid matrix at 77 K were compared with those of the corresponding carbazoles 1 – 6 . The dynamic properties of the lowest excited singlet and triplet states (τf, τp, ?f, and ?p) were measured under the same experimental conditions. The intramolecular spin–orbital‐coupling effect of the Br‐atom and NO2 group on the spectroscopic data, photophysical parameters, and on the photo reactivity were also briefly analyzed. 相似文献
5.
Maria A. Ponce Olga I. Tarzi Rosa Erra-Balsells 《Journal of heterocyclic chemistry》2003,40(3):419-426
β‐Carbolines (1‐5) undergo electrophilic aromatic substitution with N‐chlorosuccinimide and N‐chlorobenzotriazole under different experimental conditions. Although 6‐chloro and 8‐chloro‐nor‐har‐mane ( 1a and 1b ) and 6‐chloro and 8‐chloro‐harmane ( 2a and 2b ) obtained by chlorination with sodium hypochlorite of nor‐harmane (1) and harmane (2) were isolated and fully characterized recently, other chloroderivatives of nor‐harmane and harmane have never been described. The preparation and subsequent isolation, purification and full characterization of the dichloroderivatives 1c and 2c are reported (mp, Rf, 1H nmr, 13C nmr and ms) together with the preparation, isolation and charaterization, for the first time, of the chloroderivatives obtained from harmine (3a‐3c) , harmol (4a‐4b) and 7‐acetylharmol (5a‐5c) . As chlorinating reagent N‐chlorosuccinimide and N‐chlorobenzotriazole in solution as well as the β‐carboline ‐N‐chlorosuccinimide solid mixture have been used and their uses have been compared. Gc (tR) and gc‐ms (m/z) data for other monochloro derivative of nor‐harmane (1d) and monochloro‐ and dichloroderivatives of harmane ( 2d and 2e‐2f ), obtained in trace amounts, are also included (Scheme 1 and Table I). Semiempirical AM1 and PM3 calculations have been performed in order to predict reactivity in terms of the energies of HOMO‐LUMO difference and in terms of the charge density of β‐carbolines (1‐5) and chloro‐β‐carbolines ( 1a‐1c, 2a‐2c, 3a‐3c, 4a‐4b , and 5a‐5c ) (Scheme 1). Theoretical and experimental results are discussed briefly. 相似文献
6.
Andrzej Malankiewicz Ewa Michalik Andrzej Kowalski 《Journal of heterocyclic chemistry》2003,40(2):201-206
The 1H and 13C nmr spectra of the rotational isomers 3a and 3b of 6‐N‐methyl‐N‐formylaminomefhyl)‐thioquinanthrene were completely assigned with a combination of 1D and 2D nmr techniques. The key‐parts of this methodology were long‐range proton‐carbon correlations and NOE experiments with N‐methyl‐N‐formylaminomethyl substituent. The X‐ray study of 4‐methyl‐2‐N‐methyl‐N‐formylaminomethyl)quinoline 4a as well as 1H and 13C nmr spectra show that N‐methyl‐N‐formylaminomethyl substituent in 4a and 4b has a different steric arrangement than the same substituent in 3a and 3b . 相似文献
7.
The compounds 5‐ethoxycarbonyl‐1,6‐dimethyl‐4‐(3‐nitrophenyl)‐3,4‐dihydropyrimidin‐2(lH)‐one (5) and 5‐ethoxycarbonyl‐1‐phenyl‐6‐methyl‐4‐(3‐nitrophenyl)‐3,4‐dihydropyrimidin‐2(lH)‐one (1) were prepared by the Biginelli condensation method and they converted to eight N‐3 substituted dihydropyrimidines using NaH and various electrophiles (ClCO2Et, TsCl, Ac2O, AcCl and PhCOCl). Compound (1) was mono‐brominated at the C6‐methyl group using bromine solution. Reaction of the bromo derivative with amino nucleophiles such as methyl amine and cyclohexyl amine produced two pyrrolo‐pyrimidine derivatives. All the compounds except 5‐ethoxycarbonyl‐1‐phenyl‐6‐methyl‐4‐(3‐nitrophenyl)‐3,4‐dihydropyrimidin‐2(lH)‐one ( 4 ) were purified by recrystallization methods. The structure of all the new compounds was confirmed using FT‐ir,1H nmr, 13C nmr spectral and elemental analyses methods. 相似文献
8.
《Journal of heterocyclic chemistry》2018,55(4):943-945
Glucosamine hydrochloride 1 was treated with 1,3‐dicarbonyl compounds to obtain 2‐methyl‐5‐(1,2,3,4‐tetrahydroxy‐butyl) pyrrole 2a and 2b , respectively. Under the role of NaIO4, 2a and 2b were successfully transformed into the related 5‐formal pyrrole derivative 3a and 3b , respectively. Compounds 4a – 4d and 5a – 5e were obtained by reacting 3a and 3b with chlorinated hydrocarbons by alkylation reactions, respectively. The structures of all new products were confirmed by IR, NMR, and HRMS spectra. 相似文献
9.
Ismail I. Fasfous Mustafa M. El‐Abadelah Salim S. Sabri 《Journal of heterocyclic chemistry》2002,39(1):225-227
The synthesis of new pyrazolo[4,3‐c]β‐carbolines ( 8a,b ) is achieved by condensation of the appropriate aldehyde with 3‐(4‐amino‐1,3‐dimethylpyrazol‐5‐yl)indole ( 4 ) under Pictet‐Spengler reaction conditions. Regioselective cyclization occurred at the usual indole C‐2 position as evidenced from the 1H‐and 13C nmr spectra of 8a,b which lack the pyrrolic H‐2 signal, present in 4 (δ 7.26, 1H, d, Jch‐NH = 2‐5 Hz). 相似文献
10.
Sohail Saeed Naghmana Rashid Peter G. Jones Arifa Tahir 《Journal of heterocyclic chemistry》2011,48(1):74-82
A series of new N‐Substituted‐N′‐(4,6‐dimethylpyrimidin‐2‐yl)‐thiourea derivatives ( 3a , 3b , 3c , 3d ) and related fused heterocyclic compounds ( 4a , 4b , 4c , 4d ) were synthesized using tetrabutylammonium bromide as phase transfer catalyst (PTC). N‐[(2E)‐5,7‐dimethyl‐2H‐[1,2,4] thiadiazolo [2,3‐a] pyrimidin‐2‐ylidene] derivatives ( 4a , 4b , 4c , 4d ) were prepared by oxidative cyclization of 3a , 3b , 3c , 3d . The structures of these novel compounds were characterized by IR, 1H NMR, 13C NMR, mass spectrometry, and the elemental analysis. The crystal structures were determined from single crystal X‐ray diffraction data. The results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms and showed higher activity against fungi than bacteria. Compounds 3d and 3a exhibited the greatest antimicrobial activity. J. Heterocyclic Chem., 2011. 相似文献
11.
Eduardo Corts Corts Cristina A. Corts Romero Olivia García Mellado 《Journal of heterocyclic chemistry》2002,39(6):1321-1324
A series of eleven new 2‐methylthio‐3H‐7‐[(o‐; m‐ and p‐substituted) phenoxy]‐4‐(p‐substituted‐phenyl)‐[1,5]benzodiazepines, which have potentially useful pharmacological activities, has been synthesized by condensing the 4‐[(o‐; m‐ and p‐R1)phenoxy]‐1,2‐phenylendiamines with 3,3‐dimercapto‐1‐(p‐R2‐phenyl)‐2‐propen‐1‐one. Afterward the lH‐[1,5]benzodiazepine‐2‐thiones obtained were treated with sodium hydride and methyl iodide. The structure of all products was corroborated by ir, 1H nmr, 13C nmr and ms. 相似文献
12.
Influence of Halogen Substitution in the Ligand Sphere on the Antitumor and Antibacterial Activity of Half‐sandwich Ruthenium(II) Complexes [RuX(η6‐arene)(C5H4N‐2‐CH=N‐Ar)]+ 下载免费PDF全文
Joel M. Gichumbi Bernard Omondi Geraldine Lazarus Moganavelli Singh Nazia Shaikh Hafizah Y. Chenia Holger B. Friedrich 《无机化学与普通化学杂志》2017,643(11):699-711
New complexes [(η6‐p‐cymene)Ru(C5H4N‐2‐CH=N–Ar)X]PF6 [X = Br ( 1 ), I ( 2 ); Ar = 4‐fluorophenyl ( a ), 4‐chlorophenyl ( b ), 4‐bromophenyl ( c ), 4‐iodophenyl ( d ), 2,5‐dichlorophenyl ( e )] were prepared, as well as 3a – 3e (X = Cl) and the new complexes [(η6‐arene)RuCl(N‐N)]PF6 (arene = C6H5OCH2CH2OH, N‐N = 2,2′‐bipyridine ( 4 ), 2,6‐(dimethylphenyl)‐pyridin‐2‐yl‐methylene amine ( 5 ), 2,6‐(diisopropylphenyl)‐pyridin‐2‐yl‐methylene amine ( 6 ); arene = p‐cymene, N‐N = 4‐(aminophenyl)‐pyridin‐2‐yl‐methylene amine ( 7 )]. X‐ray diffraction studies were performed for 1a , 1b , 1c , 1d , 2b , 5 , and 7 . Cytotoxicities of 1a – 1d and 2 were established versus human cancer cells epithelial colorectal adenocarcinoma (Caco‐2) (IC50: 35.8–631.0 μM), breast adenocarcinoma (MCF7) (IC50: 36.3–128.8.0 μM), and hepatocellular carcinoma (HepG2) (IC50: 60.6–439.8 μM), 3a – 3e were tested against HepG2 and Caco‐2, and 4 – 7 were tested against Caco‐2. 1 – 7 were tested against non‐cancerous human epithelial kidney cells. 1 and 2 were more selective towards tumor cells than the anticancer drug 5‐fluorouracil (5‐FU), but 3a – 3e (X = Cl) were not selective. 1 and 2 had good activity against MCF7, some with lower IC50 than 5‐FU. Complexes with X = Br or I had moderate activity against Caco‐2 and HepG2, but those with Cl were inactive. Antibacterial activities of 1a , 2b , 3a , and 7 were tested against antibacterial susceptible and resistant Gram‐negative and ‐positive bacteria. 1a , 2b , and 3a showed activity against methicillin‐resistant S. aureus (MIC = 31–2000 μg · mL–1). 相似文献
13.
Walid Fathalla Pavel Pazdera Michal ajan Jaromír Marek 《Journal of heterocyclic chemistry》2002,39(6):1145-1152
Regioselective reactions of morpholine‐1‐carbothioic acid (2‐phenyl‐3H‐quinazolin‐4‐ylidene) amide ( 1 ) with electrophiles and nucleophiles were studied. The compound ( 1 ) reacts with alkyl halides in basic medium to afford S‐substituted isothiourea derivatives, with amines to give 1,1‐disubstituted‐3‐(2‐phenyl‐3H‐quinazolin‐4‐ylidene) thioureas and l‐substituted‐3‐(2‐phenyl‐quinazolin‐4‐yl) thioureas via transami‐nation reaction. The reaction of ( 1 ) with amines in the presence of H2O2 provided N4‐disubstituted‐N'4‐(2‐phenylquinazolin‐4‐yl)morpholin‐4‐carboximidamide via oxidative desulfurization. Estimation of reactivity sites on ( 1 ) was supported using the ab initio (HF/6‐31G**) quantum chemistry calculations. The ir, 1H nmr, 13C nmr, mass spectroscopy and x‐ray identified the isolated products. 相似文献
14.
Albert Lévai József Jekő Tímea Gondos András Simon Gábor Tóth 《Journal of heterocyclic chemistry》2007,44(6):1453-1458
3‐(2‐Aryl‐2,3‐dihydro‐benzo[b][1,4]thiazepin‐4‐yl)chromen‐2‐ones ( 2a, e, f ) and (Z)‐3‐(2,3‐dihydro‐2‐arylbenzo[b][1,4]thiazepin‐4(5H)‐ylidene)chroman‐2‐ones ( 3a‐f ) have been synthesized by the reaction of 3‐aryl‐1‐(3‐coumarinyl)propen‐1‐ones ( 1a‐f ) with 2‐aminothiophenol in a hot mixture of toluene and acetic acid. Structures of all new compounds and their complete 1H and 13C assignments were achieved applying different one‐ and two‐dimensional nmr experiments in combination with various spectroscopic techniques. 相似文献
15.
Synthesis,Antiviral, and Antimicrobial Activity of N‐ and S‐Alkylated Phthalazine Derivatives 下载免费PDF全文
Ahmed H. Moustafa Hassan A. El‐Sayed Rasha A. Abd El‐Hady Abdelfattah Z. Haikal Maher El‐Hashash 《Journal of heterocyclic chemistry》2016,53(3):789-799
A series of N‐alkylphthalazinone were synthesized by the reaction of phthalazin‐1(2H)‐one derivatives 1a , 1b , 1c with alkylating agents namely, propargyl, allyl bromide, epichlorohydrin, 1,3‐dichloro‐2‐propanol, 4‐bromobutylacetate, and 1‐(bromomethoxy)ethyl acetate to give the corresponding N‐alkylphthalazinone 2a , 2b , 2c , 3a , 3b , 3c , 5a , 5b , 5c , 6a , 6b , 6c , 7a , 7b , 7c , and 9a , 9b , 9c . Alkylation of phthalazin‐1(2H)‐thione to give a series from S‐alkylphthalazine 12 , 13 , 14 and thioglycosides 15 and 17 was performed. Deprotection of compounds 7a , 7b , 7c , 9a , 9b , 9c , 15 , and 17 resulted in the formation of the corresponding products 8a , 8b , 8c , 10a , 10b , 10c , 16 , and 18 . The structure of newly synthesized compounds was assigned by IR, 1H, 13C NMR, and elemental analysis. Some of these compounds were screened for antiviral and antimicrobial activity. 相似文献
16.
Khodayar Gholivand Nilufar Dorosti Fatemeh Ghaziany Manouchehr Mirshahi Sina Sarikhani 《Heteroatom Chemistry》2012,23(1):74-83
A new series of N‐phosphinylureas 5b, 6a–7c was synthesized and characterized by 1H, 13C, 31P NMR, IR, and elemental analysis. The three‐dimensional structure of 5b has been determined by X‐ray crystallography. The crystal structure revealed the existence of four independent molecules. All structures form two chains with different arrangements and connect to each other via hydrogen bonds to produce two‐dimensional polymeric chains. The cytotoxicity of cyclophosphamide (a standard antitumor compound) and its nine analogues with formula R1C6H4 NHC(O)NHP(O)XCH2C(R2)2 CH2Y(X = Y = NH, R2 = CH3, R1 = H ( 5a ), CH3 ( 5b ), NO2 ( 5c ), X = O, Y = NH, R2 = H, R1 = H ( 6a , CH3 ( 6b ), NO2 ( 6c ), and X = Y = O, R2 = CH3, R1 = H ( 7a ), CH3 ( 7b ), NO2 ( 7c )) as well as phenyl urea were evaluated in vitro against three human tumor cell lines K562, MDA‐MB‐231, and HepG2. The results showed that most of the compounds have significant activity against the selected cell lines. Also, HepG2 cells were more sensitive to all the tested compounds than other cell lines. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:74–83, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20754 相似文献
17.
《Journal of heterocyclic chemistry》2017,54(4):2471-2482
An eco‐friendly method has been developed for the synthesis of 2‐amino‐4‐(9H‐carbazole‐3‐yl)thiophene‐3‐carbonitriles from preliminary carbazole ( 1 ) through an intermediate of 2‐(1‐(9H‐carbazole‐3‐yl)ethylidene)malononitriles using the Knoevenagel condensation followed by the Gewald reaction. On the other hand, the target compounds could also be prepared in a one‐pot three‐component manner by treating equimolar quantities of 1‐(9H‐carbazole‐3‐yl)ethanone ( 3 ), malononitrile, and elemental sulfur. The merits of this preparation are mild reaction conditions. The Gewald reaction is executed with inorganic base NaHCO3 (H2O) in tetrahydrofuran, easy work‐up procedure with good yields. 相似文献
18.
Dennis Rottschäfer Beate Neumann Dr. Hans‐Georg Stammler Dr. Maurice van Gastel Dr. Diego M. Andrada Priv.‐Doz. Dr. Rajendra S. Ghadwal 《Angewandte Chemie (International ed. in English)》2018,57(17):4765-4768
One‐electron reduction of C2‐arylated 1,3‐imidazoli(ni)um salts (IPrAr)Br (Ar=Ph, 3 a ; 4‐DMP, 3 b ; 4‐DMP=4‐Me2NC6H4) and (SIPrAr)I (Ar=Ph, 4 a ; 4‐Tol, 4 b ) derived from classical NHCs (IPr=:C{N(2,6‐iPr2C6H3)}2CHCH, 1 ; SIPr=:C{N(2,6‐iPr2C6H3)}2CH2CH2, 2 ) gave radicals [(IPrAr)]. (Ar=Ph, 5 a ; 4‐DMP, 5 b ) and [(SIPrAr)]. (Ar=Ph, 6 a ; 4‐Tol, 6 b ). Each of 5 a , b and 6 a , b exhibited a doublet EPR signal, a characteristic of monoradical species. The first solid‐state characterization of NHC‐derived carbon‐centered radicals 6 a , b by single‐crystal X‐ray diffraction is reported. DFT calculations indicate that the unpaired electron is mainly located at the original carbene carbon atom and stabilized by partial delocalization over the adjacent aryl group. 相似文献
19.
A series of Zn (II), Pd (II) and Cd (II) complexes, [(L) n MX 2 ] m (L = L‐a–L‐c; M = Zn, Pd; X = Cl; M = Cd; X = Br; n, m = 1 or 2), containing 4‐methoxy‐N‐(pyridin‐2‐ylmethylene) aniline ( L‐a ), 4‐methoxy‐N‐(pyridin‐2‐ylmethyl) aniline ( L‐b ) and 4‐methoxy‐N‐methyl‐N‐(pyridin‐2‐ylmethyl) aniline ( L‐c ) have been synthesized and characterized. The X‐ray crystal structures of Pd (II) complexes [L 1 PdCl 2 ] (L = L‐b and L‐c) revealed distorted square planar geometries obtained via coordinative interaction of the nitrogen atoms of pyridine and amine moieties and two chloro ligands. The geometry around Zn (II) center in [(L‐a)ZnCl 2 ] and [(L‐c)ZnCl 2 ] can be best described as distorted tetrahedral, whereas [(L‐b) 2 ZnCl 2 ] and [(L‐b) 2 CdBr 2 ] achieved 6‐coordinated octahedral geometries around Zn and Cd centers through 2‐equivalent ligands, respectively. In addition, a dimeric [(L‐c)Cd(μ ‐ Br)Br] 2 complex exhibited typical 5‐coordinated trigonal bipyramidal geometry around Cd center. The polymerization of methyl methacrylate in the presence of modified methylaluminoxane was evaluated by all the synthesized complexes at 60°C. Among these complexes, [(L‐b)PdCl 2 ] showed the highest catalytic activity [3.80 × 104 g poly (methyl methacrylate) (PMMA)/mol Pd hr?1], yielding high molecular weight (9.12 × 105 g mol?1) PMMA. Syndio‐enriched PMMA (characterized using 1H‐NMR spectroscopy) of about 0.68 was obtained with Tg in the range 120–128°C. Unlike imine and amine moieties, the introduction of N‐methyl moiety has an adverse effect on the catalytic activity, but the syndiotacticity remained unaffected. 相似文献
20.
The dibenzofuran‐ and carbazole‐substituted oximes or methyloximes 5 – 10 were prepared and evaluated for their cytotoxic and antiplatelet activities. These compounds were synthesized via alkylation of dibenzofuran‐2‐ol or 9H‐carbazol‐2‐ol with α‐halocarbonyl reagents, followed by reaction with NH2OH or NH2OMe (Scheme). A preliminary anticancer assay indicated that the oxime‐type dibenzofuran derivatives 5 and 7a – d are active, while the corresponding oxime ethers 9b and 9c are inactive at the same concentration. Therefore, a H‐bond‐donating group seems to be crucial for cytotoxicity. Among the compounds tested, 2‐[(dibenzo[b,d]furan‐2‐yl)oxy]‐1‐(4‐methoxyphenyl)ethan‐1‐one O‐methyloxime ( 9c ) exhibited potent inhibitory activity against platelet aggregation induced by arachidonic acid, with an IC50 value of 14.87 μM , without being cytotoxic at a concentration of 100 μM . 相似文献