- Scalable Negishi Coupling between Organozinc Compounds and (Hetero)Aryl Bromides under Aerobic Conditions when using Bulk Water or Deep Eutectic Solvents with no Additional Ligands
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Pd-catalyzed Negishi cross-coupling reactions between organozinc compounds and (hetero)aryl bromides have been reported when using bulk water as the reaction medium in the presence of NaCl or the biodegradable choline chloride/urea eutectic mixture. Both C(sp3)-C(sp2) and C(sp2)-C(sp2) couplings have been found to proceed smoothly, with high chemoselectivity, under mild conditions (room temperature or 60 °C) in air, and in competition with protonolysis. Additional benefits include very short reaction times (20 s), good to excellent yields (up to 98 %), wide substrate scope, and the tolerance of a variety of functional groups. The proposed novel protocol is scalable, and the practicability of the method is further highlighted by an easy recycling of both the catalyst and the eutectic mixture or water.
- Dilauro, Giuseppe,Azzollini, Claudia S.,Vitale, Paola,Salomone, Antonio,Perna, Filippo M.,Capriati, Vito
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supporting information
p. 10632 - 10636
(2021/04/09)
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- RATIONALLY DESIGNED LAWSONE DERIVATIVES AS ANTIMICROBIALS AGAINST MULTIDRUG-RESISTANT STAPHYLOCOCCUS AUREUS
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Naphthoquinone derivatives of Lawsone have been found to be effective against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). Such compounds generally contain a substituent group at the 3-position of a specific naphthoquinone compound, i.e. 2-hydroxy-1,4-naphthoquinone. One of these derivatives referred to as compound 6c in the series exhibits potent antimicrobial activity that is comparable to that of the two commercial antibiotics ofloxacin and ciprofloxacin against the two strains of methicillin sensitive Staphylococcus aureus (MSSA; ATCC 29213 and ATCC 6538). In the case of two strains of MRSA (ATCC BAA-44 and ATCC BAA-1717) that have developed drug resistance to both ofloxacin and ciprofloxacin, the antimicrobial activity of 6c can almost rival that of vancomycin and daptomycin. Furthermore, 6c is also effective against vancomycin-intermediate and daptomycin non-susceptible strain of MRSA (ATCC 700699). Besides the efficacy, 6c has a much improved drug resistance profile in comparison with the conventional antibiotics.
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- Boronic ester-linked macrocyclic lipopeptides as serine protease inhibitors targeting Escherichia coli type I signal peptidase
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Type I signal peptidase, with its vital role in bacterial viability, is a promising but underexploited antibacterial drug target. In the light of steadily increasing rates of antimicrobial resistance, we have developed novel macrocyclic lipopeptides, linking P2 and P1′ by a boronic ester warhead, capable of inhibiting Escherichia coli type I signal peptidase (EcLepB) and exhibiting good antibacterial activity. Structural modifications of the macrocyclic ring, the peptide sequence and the lipophilic tail led us to 14 novel macrocyclic boronic esters. It could be shown that macrocyclization is well tolerated in terms of EcLepB inhibition and antibacterial activity. Among the synthesized macrocycles, potent enzyme inhibitors in the low nanomolar range (e.g. compound 42f, EcLepB IC50 = 29 nM) were identified also showing good antimicrobial activity (e.g. compound 42b, E. coli WT MIC = 16 μg/mL). The unique macrocyclic boronic esters described here were based on previously published linear lipopeptidic EcLepB inhibitors in an attempt to address cytotoxicity and hemolysis. We show herein that structural changes to the macrocyclic ring influence both the cytotoxicity and hemolytic activity suggesting that the P2 to P1’ linker provide means for optimizing off-target effects. However, for the present set of compounds we were not able to separate the antibacterial activity and cytotoxic effect.
- Sza?aj, Natalia,Lu, Lu,Benediktsdottir, Andrea,Zamaratski, Edouard,Cao, Sha,Olanders, Gustav,Hedgecock, Charles,Karlén, Anders,Erdélyi, Máté,Hughes, Diarmaid,Mowbray, Sherry L.,Brandt, Peter
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supporting information
p. 1346 - 1360
(2018/09/13)
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- Metal-catalyzed formal amidation of alkenes under CO-free condition
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An effective procedure for synthesis of amides from alkenes and [Formula presented] via Pd and Fe catalysts under mild conditions is described. A series of benzamides containing various functional groups can be obtained in reasonable yield and the possible reaction pathway is proposed in this Letter.
- Zhang, Yuanyuan,Ye, Wenjing,Leng, Xue,He, Ying,Zhang, Hui,Xiao, Xiao
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p. 4203 - 4206
(2016/08/24)
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- Antimycobacterial activity evaluation, time-kill kinetic and 3D-QSAR study of C-(3-aminomethyl-cyclohexyl)-methylamine derivatives
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A series of C-(3-aminomethyl-cyclohexyl)-methylamine derivatives were synthesized and evaluated for their antitubercular activity. Some of the compounds exhibited potent activity against Mycobacterium tuberculosis H37Rv. One of the compound having t-butyl at para position of the benzene ring showed excellent activity even better than the standard drug ethambutol with MIC value 1.1 ± 0.2 μM. The time-kill kinetics study of two most active compounds showed rapid killing of the M. tuberculosis within 4 days. Additionally atom-based quantitative structure-activity relationship (QSAR) model was developed that gave a statistically satisfying result (R2) = 0.92, Q2 = 0.75, Pearson-R = 0.96 and effectively predicts the anti-tuberculosis activity of training and test set compounds.
- Kumar, Deepak,Raj, K. Kranthi,Bailey, Maiann,Alling, Torey,Parish, Tanya,Rawat, Diwan S.
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p. 1365 - 1369
(2013/03/14)
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- An unsymmetrically π-extended porphyrin-based single-crystal field-effect transistor and its anisotropic carrier-transport behavior
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Anisotropic charge transport: Single-crystal organic field-effect transistor devices derived from aggregates of thiophene-appended porphyrins display very high mobility (0.27 cm2 V-1 s-1). This behavior is due to staircase stacking of the porphyrins with distances between layers of 3.17(7) A. Furthermore, the charge-transport behavior is anisotropic owing to an anisotropic molecular arrangement in the single-crystal microplates. Copyright
- Choi, Soojung,Chae, Seung Hyun,Hoang, Mai Ha,Kim, Kyung Hwan,Huh, Jung A,Kim, Youngmee,Kim, Sung-Jin,Choi, Dong Hoon,Lee, Suk Joong
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supporting information
p. 2247 - 2251
(2013/03/28)
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- Dramatic enhancement of carrier mobility via effective secondary structural arrangement resulting from the substituents in a porphyrin transistor
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OFET devices based on single-crystals of two different porphyrin derivatives display excellent mobilities of 2.57 and 0.48 cm2 V -1 s-1. Although they generate similar J-aggregations, the dramatic enhancement of mobility obtained using porphyrin 1 is due to the well-confined secondary structural arrangement caused by substituents on the porphyrin ring.
- Choi, Soojung,Chae, Seung Hyun,Shin, Jicheol,Kim, Youngmee,Kim, Sung-Jin,Choi, Dong Hoon,Lee, Suk Joong
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supporting information
p. 3994 - 3996
(2013/07/26)
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- Heteroaromatic moieties in the sphingosine backbone of α- Galactosylceramides for noncovalent interactions with CD1d
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A series of α-GalCer analogues containing heterocyclic and aromatic moieties in the sphingosine backbone were synthesized to improve the selectivity in the Th1/Th2 cytokine profile via noncovalent interaction with three aromatic residues at the binding pocket of CD1d. In vitro and in vivo biological evaluations revealed the treatment of α-GalCer analogue (6) induced the selective stimulation of natural killer T cells to facilitate the secretion of Th2 cytokines.
- Kim, Yongju,Kim, Jonghoon,Oh, Keunhee,Lee, Dong-Sup,Park, Seung Bum
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supporting information; experimental part
p. 151 - 154
(2012/04/04)
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- COMPOSITIONS AND METHODS FOR INHIBITING SPHINGOSINE KINASE
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Amidine analogs that can inhibit the activity of sphingosine kinase 1 and sphingosine kinase 2 (SphK1 and SphK2) are provided. The compounds can prevent angiogenesis in tumor cells.
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Page/Page column 35
(2009/12/27)
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- Orthoamides, LIX [1]. Formyl-aalen [tris(diformylamino)methane] - A new formylating reagent for activated aromatic compounds
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In the presence of strong Lewis acids such as aluminum chloride or boron trichloride, formyl-aalen [tris(diformylamino)methane] (3) acts as a formylating reagent for aromatic alkane compounds and aromatic ethers. The orthoamide 3 delivers three formyl groups for the formylation process. Thus toluene, cumene, tert-butylbenzene, hexylbenzene, o-xylene, p-cymene, biphenyl, anisole, diphenylether and 1,3-dimethoxybenzene can be formylated in 1,2-dichloroethane. In these reactions, 3 and aluminum chloride should be used in a molar ratio of 1:6 to 1:9.
- Kantlehner, Willi,Haug, Erwin,Scherr, Oliver,Ziegler, Georg
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p. 1295 - 1304
(2007/10/03)
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- New formylating agents - Preparative procedures and mechanistic investigations
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The reactivity of new formylating agents related to formamide has been investigated both experimentally and theoretically. The reaction in 1,2-dichloroethane between tris(diformylamino)methane (2) and several arenes, catalyzed by AlCl3 or BCl3, was shown to proceed in good yields to afford the corresponding para-substituted aldehydes. The nature of the active electrophilic species was also investigated theoretically. Thus, the relative stability of the O- and N-protonated forms, as well as those of AlCl3 adducts, of several formylating agents - diformamide, triformamide, N,N,N′,N′-tetraformylhydrazine, and tris(diformylamino)methane - were determined in the gas phase and in water or DCE by means of DFT calculations at the B3LYP/6-311++G(d,p) level, the solvents being modeled with the IPCM method. The amide oxygen atom in all cases appeared to be the most basic site, both in the Bronsted and Lewis sense, constituting a first step towards the understanding of the mechanism of this reaction.
- Bagno, Alessandro,Kantlehner, Willi,Scherr, Oliver,Vetter, Jens,Ziegler, Georg
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p. 2947 - 2954
(2007/10/03)
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- Orthoamides. LIII. A New Synthesis for Aromatic Aldehydes of Wide Scope
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Diformamide (1) reacts with activated aromatic compounds like toluene, anisole, m-xylene, 1,2-dimethoxybenzene in the presence of AlCl3 to give N-(diarylmethyl)-formamides 2a-d, the corresponding aromatic aldehydes 3-6 are formed as by-products in low yields. From N,N-dimethylaniline and 1/AlCl3 the triphenylmethane derivative 7 can be obtained. The reaction of anisole with N-methyl-diformamide (9) affords the formamide 10. The mixture of formamide, P4O10 and AlCl3 reveals to be a reagent which is capable to formylate toluene and anisole, resp. Triformamide (14)/AlCl3 is an effective formylating system which allows the preparation of aromatic aldehydes (e.g. 3,4,17-32) from the corresponding aromatic hydrocarbons. Aluminiumchloride can be replaced by borontrichloride. The yields of the formylation reactions depend strongly from the reaction conditions (molar ratio: aromatic hydrocarbon/ AlCl3/14; solvent, reaction temperature). The scope of the reaction covers nearly complete those of the Gattermann-Koch-, Gattermann- and Vilsmeier-Haack-reaction.
- Kantlehner, Willi,Vettel, Markus,Gissel, Alexander,Haug, Erwin,Ziegler, Georg,Ciesielski, Michael,Scherr, Oliver,Haas, Richard
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p. 297 - 310
(2007/10/03)
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- Functionalized AB-type monomers for Suzuki polycondensation
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A high yield synthesis of two phenylene and biphenylene derived AB-type monomers for Suzuki polycondensation is described. They carry solubilizing alkyl groups and free and methyl-protected hydroxy functional groups for further modifications.
- Frahn,Schluter
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p. 1301 - 1304
(2007/10/03)
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- Palladium-Catalyzed Cross-Coupling Reaction of Alkyltrifluorosilanes with Aryl Halides
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A cross-coupling reaction of alkyltrifluorosilanes with aryl halides was achieved using a catalytic amount of tetrakis-(triphenylphosphine)palladium(0) and excess of tetrabutylammonium fluoride (TBAF) at 100°C with high chemoselectitvity. Functional groups like nitro, ketone carbonyl, and formyl tolerated the coupling conditions. Because potassium(18-crown-6) alkyltetrafluorosilicates also underwent a cross-coupling reaction in the presence of an additional molar amount of TBAF, the active species of the coupling reaction was assumed to be pentacoordinate silicates. TBAF in excess was considered to be required for trapping the tetrafluorosilane produced in the catalytic cycle of the cross-coupling reaction.
- Matsuhashi, Hayao,Asai, Satoshi,Hirabayashi, Kazunori,Hatanaka, Yasuo,Mori, Atsunori,Hiyama, Tamejiro
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p. 437 - 444
(2007/10/03)
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- Synthesis and characterization of stilbene derivatives for possible incorporation as smart additives in polymers used as packaging films
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Several series of stilbene derivatives for possible use as smart additives in polymers used as packaging films have been prepared and characterized. Differential scanning calorimetry was performed on some of the stilbenes in order to determine any liquid crystal properties. Those compounds which had multiple phase transitions were also shown to have two liquid crystalline phases according to optical microscopy.
- Day, Gary M.,Howell, Owen T.,Metzler, Michael R.,Woodgate, Paul D.
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p. 425 - 434
(2007/10/03)
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- Photoionization of (p-alkylphenyl)triphenylporphyrins in neutral and positively and negatively charged vesicles: Effects of alkyl chain length and addition of chloroalkanes
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The photoionization of (p-alkylphenyl)triphenylporphyrins (CnPtPP) in cationic dioctadecyldimethylammonium chloride (DODAC), neutral dipalmitoylphosphatidylcholine (DPPC), and anionic dihexadecyl phosphate (DHP) frozen vesicles has been studied by electron spin resonance (ESR) with visible light irradiation at 77 K with and without addition of chloroalkanes (CCl4, CHCl3, CH2Cl2, or CH3CH2CH2Cl) as electron acceptors. CnPtPP (n = 3, 6, 9, and 12) were synthesized and used to study the effects of alkyl chain length. The photoionization efficiency was found to decrease with increasing alkyl chain length of CnPtPP. The relative photoyield of the porphyrin cation radical (CnPtPP+) measured by ESR decreased in the order DODAC > DPPC > DHP. The addition of CCl4, CHCl3, CH2Cl2, or CH3CH2CH2Cl into C9PtPP/DHP vesicles enhanced the C9PtPP+ radical photoyield. All four chloroalkanes acted as better electron acceptors in competition with water at the vesicle interface. The results are discussed in terms of the alkyl chain length of CnPtPP, the vesicle surface charge, and the effects of chloroalkanes as electron acceptors.
- Sung-Suh, Hyung Mi,Kevan, Larry
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p. 1414 - 1418
(2007/10/03)
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- Photochemical behavior of micellized 4-(4′-alkylstyryl)pyridinium salts
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New photochromic surfactants, l-alkyl-4-(4′-alkylstyryl)lpyridinium halides (CnStzRX; n = 0, 4, 6, 8; R = Me, Et, CH2CH2OH, n-Bu, n-C9H19; X = Br, I), were synthesized and the photochemical behavior of their micellar aggregates in water was characterized in relation to non-micellizing l-methyl-4-stilbazolium ions. Reversible trans-cis isomerization through a photothermal cycle was observed for the micellized CnStzRX. Furthermore, photoreactions upon prolonged irradiation of CnStzRX micelles resulted in a 3-31% formation of thermodynamically least stable syn-head-to-head and ca. 3% of anti- head-to-head dimers. These findings indicate that the self aggregation process of CnStzRX may provide some topologically organized microenvironment affecting the steric and like-charge repulsions of the aggregate components.
- Kozlecki, Tomasz,Wilk, Kazimiera A.
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p. 645 - 651
(2007/10/03)
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- Synthesis of p-Alkyl-, p-Alkoxy-, and p-Acyloxycinnamates with trans-4-Phenylcyclohexyl and 4-Biphenylyl Fragments and Their Mesomorphic Properties
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Acylation of trans-4-phenylcyclohexanol and p-cyano-p'-hydroxybiphenyl with p-n-alkyl-, p-n-alkoxy-, and p-n-alkanoyloxycinnamoyl chlorides yields corresponding cinnamates.
- Bykova, V. V.,Zharova, M. A.,Maidachenko, G. G.
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p. 1143 - 1145
(2007/10/03)
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- New potent antagonists of leukotrienes C4 and D4. 1. Synthesis and structure-activity relationships
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(p-Amylcinnamoyl)anthranilic acid (3a) had moderate antagonist activities against LTD4-induced smooth muscle contraction on guinea pig ileum and LTC4-induced bronchoconstriction in anesthetized guinea pigs. Modifications were made in the hydrophobic part (cinnamoyl moiety) and the hydrophilic part (anthranilate moiety) of 3a. A series of 8-(benzoylamino)-2-tetrazol-5-yl-1,4-benzodioxans and 8-(benzoylamino)-2-tetrazol-5-yl-4-oxo-4H-1-benzopyrans were revealed to be potent antagonists of leukotrienes C4 and D4. Among both series, ONO-RS-347 (18k) and ONO-RS411 (19h) were the most potent and orally active antagonists, respectively. Structure-activity relationships are discussed.
- Nakai,Konno,Kosuge,Sakuyama,Toda,Arai,Obata,Katsube,Miyamoto,Okegawa,Kawasaki
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- Synthesis of Unbranched 4-Alkylbenzaldehydes
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The preparation of unbranched 4-alkylbenzaldehydes free of positional and branched-chain isomers by different methods is described.A one-step preparation of the aldehydes is reported which involves the direct hydrogenation of a Friedel-Craft's complex in the presence of Pd/C catalyst.
- Osman, Maged A.
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p. 2448 - 2449
(2007/10/02)
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- Antirhinovirus agents
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Compounds of the following general structure are useful as antirhinovirus agents: STR1 wherein Y is a bond, oxygen or divalent sulfur; R is a straight or branched hydrocarbon chain having from 6 to 20 carbon atoms and is saturated or unsaturated having from 1 to 4 double bonds when R has from 10 to 20 carbon atoms and 1 or 2 double bonds when R has from 6 to 9 carbon atoms; and R1 is hydrogen or a straight or branched alkyl group of from 1 to 4 carbon atoms.
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- LOW-MELTING NEMATIC 4,4 prime -BIS-(ALKYLBENZAL)-2-CHLORO-1,4-PHENYLENEDIAMINES.
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A series of 4,4 prime -bis(alkylbenzal)-2-chloro-1,4-phenylenediamines were prepared and their mesomorphic behavior characterized. All homologues showed nematic behavior with broad mesophases and rather low-melting points. The mesomorphic behavior is compared with that obtained from the 4,4 prime -bis-(alkoxybenzal)-1,4-phenylenediamine series and the 4,4 prime -bis-(alkoxybenzal)-2-chloro-1,4-phenylenediamine series.
- Cole,Sowa
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p. 149 - 153,150, 151
(2007/10/09)
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