- Second-generation aryl isonitrile compounds targeting multidrug-resistant Staphylococcus aureus
-
Antibiotic resistance remains a major global public health threat that requires sustained discovery of novel antibacterial agents with unexploited scaffolds. Structure-activity relationship of the first-generation aryl isonitrile compounds we synthesized led to an initial lead molecule that informed the synthesis of a second-generation of aryl isonitriles. From this new series of 20 compounds, three analogues inhibited growth of methicillin-resistant Staphylococcus aureus (MRSA) (from 1 to 4 μM) and were safe to human keratinocytes. Compound 19, with an additional isonitrile group exhibited improved activity against MRSA compared to the first-generation lead compound. This compound emerged as a candidate worthy of further investigation and further reinforced the importance of the isonitrile functionality in the compounds’ anti-MRSA activity. In a murine skin wound model, 19 significantly reduced the burden of MRSA, similar to the antibiotic fusidic acid. In summary, 19 was identified as a new lead aryl isonitrile compound effective against MRSA.
- Kyei-Baffour, Kwaku,Mohammad, Haroon,Seleem, Mohamed N.,Dai, Mingji
-
supporting information
p. 1845 - 1854
(2019/03/28)
-
- Olefin cross-metathesis/Suzuki-Miyaura reactions on vinylphenylboronic acid pinacol esters
-
A series of alkenyl phenylboronic acid pinacol esters has been synthesized via an olefin cross-metathesis reaction of vinylphenylboronic acid pinacol ester derivatives. After catalytic hydrogenation, the resulting boronates were coupled via a microwave-mediated Suzuki-Miyaura reaction to afford a library of biarylethyl aryl and biarylethyl cycloalkyl derivatives. A complementary reaction sequence involved an initial Suzuki-Miyaura coupling.
- Baltus, Christine B.,Chuckowree, Irina S.,Press, Neil J.,Day, Iain J.,Coles, Simon J.,Tizzard, Graham J.,Spencer, John
-
supporting information
p. 1211 - 1217
(2013/03/13)
-
- Synthesis of stilbene analogues by one-pot oxidation-Wittig and oxidation-Wittig-Heck reaction
-
Synthesis of symmetrical (and unsymmetrical) stilbene derivatives is achieved by a combination of one-pot steps of Kornblum type oxidation of benzyl halide, its simultaneous in situ formation of phosphonium salt, and subsequently their Wittig reaction. In other variant it is oxidized to aldehyde, treated with ylide generated from phosphonium salt (CH3PPh3X) to give styrene, and subjected to Pd catalyzed Heck reaction with arylhalide to give stilbenes as the three-step one-pot sequence.
- Saiyed, Akeel S.,Patel, Krupa N.,Kamath, Bola V.,Bedekar, Ashutosh V.
-
supporting information; experimental part
p. 4692 - 4696
(2012/09/10)
-
- Dehydrogenation of nitro derivatives of bibenzyl to corresponding nitro stilbene with dioxygen catalyzed by 2,2,6,6-tetramethylpiperidine-1-oxyl
-
A simple and effective oxidative dehydrogenation of nitro derivatives of bibenzyl was developed using a mixture of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and metal salts as catalyst under an atmospheric pressure of oxygen. The oxidation of several nitro derivatives of bibenzyl led to corresponding nitro stilbene in good yields, and the yields increased with the increase in the substituted nitro group on the bibenzyl. For example, the aerobic dehydrogenation of 2,2,4,4,6,6-hexanitrobibenzyl in the presence of a catalytic amount of TEMPO with metal salts gave 2,2,4,4,6,6-hexanitrostilbene in 81 % yield and 4,4-dinitrostilbene-2,2-disulfonic acid (75 %) was obtained from 4,4-dinitrobibenzyl-2,2-disulfonic acid. Iranian Chemical Society 2012.
- Lu, Tingting,Lu, Ming
-
p. 971 - 975
(2013/02/25)
-
- On the dual role of N-heterocyclic carbenes as bases and nucleophiles in reactions with organic halides
-
The synthetic consequences of different basicities, nucleophilicities, and sterics of N-heterocyclic carbenes have been studied in reactions of imidazolin-2-ylidenes with organic halides. Highly nucleophilic and less basic carbenes cleanly gave alkyli-deneimidazolines, the deoxy analogues of Breslow-type intermediates. More basic NHCs engaged in unwanted deprotonation or dehydrohalogenation reactions. Georg Thieme Verlag Stuttgart. New York.
- Knappke, Christiane E. I.,Arduengo, Anthony J.,Jiao, Haijun,Neudoerfl, Joerg-Martin,Jacobivonwangelin, Axel
-
scheme or table
p. 3784 - 3795
(2012/01/11)
-
- Solvolytic stereoselective debromination of vic-dibromides with HMPA
-
A simple and efficient procedure for the debromination of vic-dibromides has been reported with hexamethylphosphoric triamide at 155-160°C under a nitrogen atmosphere without the aid of any reagent.
- Khurana,Bansal,Chauhan
-
p. 1089 - 1091
(2007/10/03)
-
- REACTIVITY OF THE ACIDS OF TRIVALENT PHOSPHORUS AND THEUR DERIVATIVES. PART II. THE REACTION OF TRIVALENT PHOSPHORUS ACID SALTS WITH THE BENZYLIC HALIDES SYSTEM
-
The reaction of the benzylic halides systems with sodium dialkylphosphites as well as the sodium salt of dibenzylphosphine oxide in THF and alcohols as the solvents is described.According to the constitution of the starting materials, the formation of the P-C bond, dehalogenation or dimerization occurs.Probable mechanisms namely SET and X-philic substitution are discussed.Key words: Benzylic halides system, dialkylphosphites, dibenzylphosphine oxide, Michaelis-Becker reaction, X-philic substitution.
- Witt, Dariusz,Rachon, Janusz
-
p. 153 - 164
(2007/10/02)
-
- Electrochemical reduction of certain fluorenyl and xanthenyl olefins
-
The reduction of certain fluorene and xanthene containing olefins at a mercury electrode using cyclic voltammetry has been investigated.In DMF, fluorene-9-(4-nitrophenyl)methylene (1) reveals two distinct reversible one-electron redox waves corresponding to anion radical and dianion formation.Some other olefins particularly stilbenes (9-14) and substituted propenones (7,8) show commonality in the emergence of at least one distinct reversible reduction couple.Anion radicals of nearly all of the olefins (1-14) studied in this work generated electrochemically or by chemical 1-electron reductants, exhibited considerable stability.
- Handoo, Kishan L,Kaul, Anju
-
p. 579 - 583
(2007/10/02)
-
- C-ALKYLATION OF β-DIKETONES WITH BENZYLPYRIDINIUM SALTS. EVIDENCE FOR CHAIN RADICAL MECHANISMS
-
1-(p-Substituted benzyl)-2,4,6-triphenylpyridinium cations react with β-diketone anions by mechanisms which depend on the para-substituent.The p-methoxybenzyl derivative undergoes SN1 displacement yielding O- and C-benzylated products.The p-nitrobenzyl compound reacts by a chain radicaloid mechanism and gives high yields of C-p-nitrobenzylated diketones.The parent benzyl compound forms some C- and some O-benzylated products, together with bibenzyl, probably by a radical chain reaction which was suppressed by radical traps.
- Marquet, Jorge,Moreno-Manas, Marcial,Pacheco, Pedro,Prat, Maria,Katritzky, Alan R.,Brycki, Bogumil
-
p. 5333 - 5346
(2007/10/02)
-
- Nucleophilic C-C Linkages of 2-Nitro- and 3-Nitro-1,6-methanoannulenes
-
By "vicarious nucleophilic substitutions" of 2- and 3-nitro-1,6-methanoannulenes (2, 3) the new compounds 4 - 13 are obtained.Reactions of 2, 3 with sodium methoxide lead to the Ethers 16 and 17, oxidative coupling reactions in the presence of MnO2 to 18, and Meisenheimer complexes, followed by oxidation to the nitromethane derivatives 14 and 15. - Keywords: 1,6-Methanoannulenes, 2- and 3-nitro/ Vicarious nucleophilic substitution
- Neidlein, Richard,Lautenschlaeger, Gabriele
-
p. 493 - 498
(2007/10/02)
-
- Application of Phase-Transfer Catalysis to the Synthesis of Mono- and Bis-stilbenes and Styryls
-
A novel and convenient method has been developed for the synthesis of substituted stilbenes by the condensation of active methyl group in suitably substituted toluenes with aromatic aldehydes in aq. medium at room temperature using benzyltriethylammonium chloride as a phase-transfer catalyst.This method has also been applied for the preparation of heterocyclic styryls and extended to the synthesis of bis-stilbenes and bis-styryls using aromatic dialdehydes in place of monoaldehydes.A comparison of the results shows that the present method is superior to the conventional methods in many respects.
- Lokhande, S. B.,Rangnekar, D. W.
-
p. 485 - 488
(2007/10/02)
-
- REACTIONS AT HIGH PRESSURE, PART 18; VOLUMES OF ACTIVATION AND OF REACTION FOR THE WITTIG REACTION
-
Volumes of activation have been obtained from rate measurements between 1 and 1000 bar of reactions between triphenyl-p-nitrobenzylidenephosphorane and a series of substituted benzaldehydes.Values of ΔVexcit. lie in the range -20 to -30 cm3mol-1 and are somewhat solvent-dependent.These measurements are in agreement with the accepted reaction mechanism and suggest that the scope of the reaction may be extended by the use of high pressures.
- Isaacs, Neil S.,Abed, Obeid Hassan
-
p. 995 - 996
(2007/10/02)
-
- Electron Apportionment in Cleavage of Radical Anions. 1. Nitro-Substituted Benzyl Phenyl Ethers
-
The radical anions of 4-nitrobenzyl phenyl ethers undergo cleavage at least 10E4 times faster than the radical anions of corresponding 4-nitrophenyl benzyl ethers despite a perceived thermodynamic advantage for the latter set of reactions.It is suggested that this results reflects a kinetic advantage for cleavage reactions which take place with regioconservation of spin density.
- Maslak, Przemyslaw,Guthrie, Robert D.
-
p. 2628 - 2636
(2007/10/02)
-
- The Autoxidation of Alkylnitroaromatic Compounds in Base-catalysed Phase-transfer Catalysis by Polyethylene Glycol under Ultrasonic Radiation
-
The use of ultrasonic agitation in the base-catalysed autoxidation of alkylnitrobenzenes in polyethylene glycol phase-transfer systems changes reaction selectivity fron the usual dimeric products to the carboxylic acid.
- Neumann, Ronny,Sasson, Yoel
-
p. 616 - 617
(2007/10/02)
-
- Electron Transfer in Competition with Loss of Nitrogen in Photochemical Reactions of Aryldiazomethane with Diethylamine
-
The photolysis of aryldiazomethanes was studied as a function of aryl substituents and the p-nitro group was found to exert a special effect of product distribution.
- Tomioka, Hideo,Tabayashi, Kazuo,Izava, Yasuji
-
p. 906 - 907
(2007/10/02)
-
- A HIGHLY EFFICIENT VERSION OF THE PALLADIUM-CATALYSED ARYLATION OF ALKENES WITH ARYL BROMIDES
-
The palladium-catalysed arylation of alkenes with aryl bromides or iodides is shown to proceed in high yields at very low palladium concentration when carried out in a suitable strongly polar solvent with a carboxylate anion as base.The preferred combination is N,N-dimethylformamide with sodium acetate.The reaction is markedly dependent on the substituents in the aryl bromide, being favoured by electron-withdrawing groups.Turnover numbers up to 134,000 have been achieved.
- Spencer, Alwyn
-
p. 101 - 108
(2007/10/02)
-
- RHODIUM ION CATALYZED DECOMPOSITION OF ARYLDIAZOALKANES
-
Aryldiazomethanes are converted by rhodium(II)acetate and iodorhodium(III) tetraphenylporphyrin to cis- rather than trans-1,2-diarylethylenes.Secondary aryldiazoalkanes react with rhodium(II) acetate to give azines.
- Shankar, B.K. Ravi,Shechter, Harold
-
p. 2277 - 2280
(2007/10/02)
-
- REACTIONS OF ORGANIC ANIONS. PART C. PHASE-TRANSFER ALKYLATION OF C-H ACIDS ACTIVATED BY THE ISONITRILE FUNCTION. UNPRECENDENTED β-ELIMINATION OF THE ISONITRILE GROUP
-
Benzylation and nitrobenzylation reactions of isocyanides in a catalytic two-phase system and in some homolytic systems were studied.Elimination of the isocyanide group has been observed in the products obtained.
- Jawdosiuk, Mikolaj,Uminski, Maciej,Kmiotek-Skarzynska, Irena,Makasza, Mieczyslaw
-
p. 1309 - 1320
(2007/10/02)
-
- Proton-Transfer and Electron-Transfer Processes in Reaction of p-Nitrotoluene with Bases. A Spectrophotometric Study
-
The interaction of p-nitrotoluene (PNT) with a variety of basic systems has been studied spectrophotometrically.The bases employed, in decreasing order of base strength, were potassium hydride, dimsyl potassium, triphenylmethylpotassium, fluorenylpotassium, and potassium p-nitroanilide, while the solvents used were dimethyl sulfoxide, tetrahydrofuran, and dimethoxyethane, with 18-crown-6 ether present in the latter two cases.The major species produced in the reactions were p-nitrobenzyl anion (PNT-), p-nitrotoluene radical anion (PNT-.), and p,p'-dinitrostilbene radical anion (DNS-.).The principal processes in the PNT-base systems are believed to be (i) PNT + B- PNT- + BH; (ii) PNT + B- PNT-. + B.; (iii) PNT- + PNT PNT. + PNT-..DNS-. is formed through secondary processes via p,p'-dinitrobibenzyl.Discussion of process (i) is given in terms of the relative pKas of PNT and the respective BH species, while (ii) is analysed on the basis of the reduction potential of PNT and the oxidation potential of B-.For the case of the PNT/Ph3C- system, the electron-transfer process (ii) is kinetically preferred but this equilibrium is rapidly established.On the other hand the proton-transfer process (i) is greatly favored thermodynamically and is effectively irreversible; as a result the proton transfer predominates.This is in accord with observation of PNT- as the initially formed species in this system.The processes occurring in the other base systems are similarly analysed.The assignment of the absorption due to the p-nitrobenzyl anion is at variance with an earlier literature report deduced from examination of the PNT/t-BuOK/t-BuOH system.Electron-transfer and proton-transfer processes in the PNT/t-BuO- system are also discussed.
- Buncel, E.,Menon, B. C.
-
p. 3499 - 3507
(2007/10/02)
-
- New Olefin and Oxiran Syntheses from Carbonyl Compounds, and Diethyl Sodiophosphonate Anions and 1-Aminophosphonate Amino-anions
-
Reaction of aromatic aldehydes, and phthalic and thiophthalic anhydrides, with diethyl sodiophosphonate (1) gives the trans-stilbenes (3), 3,3'-biphthalidylidene (30), and 3,3'-bis-(2-thiophthalidylidene) (33).Similar treatment of fluorenone (8) and xanthone (17) with (1) leads to 9,9'-bis(fluororenylidene) (9) and 9,10-dihydro-9-oxophenanthrene-10-spiro-9'-fluorene (10), and to 9,9'-bixanthenylidene (18) and 9,9'-bixanthenyl (19), respectively, but the reaction using anthrone (11) as a carbonyl reagent yields only anthraquinone (12) and anthracene (13).Similar treatment using N-methylisatoic anhydride (34) and N-methylisatin (36) produces NN'-dimethylisoindigo (35).Reaction of benzaldehyde and p-chlorobenzaldehyde with diethyl 1--cyclohexylphosphonate (40) gives mainly corresponding mixtures of trans- (41a,b) and cis-stilbene epoxides (42a,b), while similar treatment of p-nitrobenzaldehyde with (40) produces 4,4'-dinitrostilbene (3e).Reaction of (8) with (40), as well as with (1), gives (9) and (10).The mechanism of formation of these products is discussed.
- Minami, Toru,Matsuzaki, Narihide,Ohshiro, Yoshiki,Agawa, Toshio
-
p. 1731 - 1738
(2007/10/02)
-
- Pyrazolopyridines. The Preparation of 1-Protected-1H-pyrazolopyridines and Attempts to Remove the 1-Substituent. Some Reactions of 1-Benzyl-1H-pyrazolopyridine and its 7-Oxide
-
1-Protected-1H-pyrazolopyridines and -1H-pyrazolopyridin-6(7H)-ones have been obtained from 1-substituted-5-aminopyrazoles , and the removal of the protecting groups has been investigated.Cyclisation of 1-substituted-5-aminopyrazoles with ethyl acetoacetate under acidic conditions or of the β-aminopropionic acid derivative (19) under the same conditions gave only the 1H-pyrazolopyridin-6(7H)-one isomer .N-Oxidation of 1-benzyl-1H-pyrazolopyridine (4) gave the 7-oxide (21) which yielded (20) and the less usual β-substitution product (22) with acetic anhydride.Nitration of either (4) or (21) gave only substitution at the para-position of the 1-benzyl substituent, but bromination or chlorination gave substitution at the 3-position of the heterocycle.
- Dorgan, Roderick J.J.,Parrick, John,Hardy, Christopher R.
-
p. 938 - 942
(2007/10/02)
-