- Copper-mediated dehydrogenative biaryl coupling of naphthylamines and 1,3-azoles
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A copper-mediated dehydrogenative biaryl cross-coupling of naphthylamines and 1,3-azoles has been developed. The key to its success is the introduction of N,N-bidentate coordination system based on the picolinamide directing group. The reaction proceeds s
- Odani, Riko,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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- A One-Pot Tandem Approach for the Synthesis of 5-(Het)aryloxazoles from Substituted (Het)aryl Methyl Alcohols and Benzyl Bromides
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A new modified van Leusen strategy has been developed for the synthesis of biologically significant 5-substituted oxazoles by the reaction of (het)aryl methyl alcohols or benzyl bromides as precursors with tosylmethylisocyanide (TosMIC) under basic conditions. This method is efficient, takes place under mild reaction conditions, and is tolerant of various functional groups with high yield.
- Vinay Kumar, Koravangala S.,Swaroop, Toreshettahally R.,Rajeev, Narasimhamurthy,Vinayaka, Ajjampura C.,Lingaraju, Gejjalagere S.,Rangappa, Kanchugarakoppal S.,Sadashiva, Maralinganadoddi P.
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- Solution-phase parallel oxazole synthesis with TosMIC
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A quaternary ammonium hydroxide ion exchange resin catalyzes the reaction of p-tolylsulfonylmethyl isocyanide (TosMIC) with aromatic aldehydes to give 5-aryloxazoles. The base and the p-tolylsulfinic acid byproduct are removed by simple filtration, result
- Kulkarni, Bheemashankar A.,Ganesan
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- Benzotriazol-1-ylmethyl isocyanide, a new synthon for CH-N=C transfer. Syntheses of α-hydroxyaldehydes, 4-ethoxy-2-oxazolines and oxazoles
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Readily prepared benzotriazol-1-ylmethyl isocyanide (BetMIC) reacts under mild conditions with ketones and aldehydes, to afford oxazolines (convertible into α-hydroxyaldehydes) and oxazoles, respectively.
- Katritzky,Chen,Yannakopoulou,Lue
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- CONVERSION OF TRIAZOLIDES INTO OXAZOLES BY FLASH-VACUUM PYROLYSIS.
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Flash-vacuum pyrolysis of azolides of 1,2,4-triazole affords 5-monosubstituted oxazoles.
- Maquestiau, A.,Puk, E.,Flammang, R.
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- Direct C-H iodination of 1,3-azoles catalysed by CuBr2
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A mild method was developed for the direct C-H iodination of 1,3-azoles catalysed by CuBr2. Compared with the traditional metalation/iodination sequences carried out with nBuLi or TMPLi (TMP = 2,2,6,6-tetramethylpiperidino), a relatively weaker base, LiOtBu, was used in the presence of 1,10-phenanthroline. Five series of 1,3-azoles, including benzoxazole, benzothiozole, N-methyl-benzoimidazole, 5-phenyloxazole and 2-phenyl-1,3,4-oxadiazole were tested and afforded the corresponding iodination products.
- Zhao, Xia,Ding, Fang,Li, Jingyu,Lu, Kui,Lu, Xiaoyu,Wang, Bin,Yu, Peng
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- Synthesis and reactivities of 1-(isocyanomethyloxy)benzotriazole as a new source of isocyanomethyl synthon
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The title compound, 1-(isocyanomethyloxy)benzotriazole (6) as a new source of isocyanomethyl synthon, was synthesized in 65% yield by the dehydration of 1-(formamidomethyloxy)benzotriazole with phosphorus oxychloride in the presence of triethylamine. Unde
- Sasaki, Hideaki
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- Nickel-catalyzed direct C-H arylation and alkenylation of heteroarenes with organosilicon reagents
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"Chemical Equation Presented" Breaking the Si-lence: The direct crosscoupling of heteroarenes with aryl- or alkenylsilanes proceeds efficiently, in the presence of a nickel catalyst, to create a wide range of aryl- and alkenyl-heteroaryl bonds efficiently (see scheme; DMAc= N.N-dimethylacetamide, bpy = 2,2′-bipyridine). This catalysis represents a new avenue for using organosilanes in the catalytic C-H functionalization chemistry.
- Hachiya, Hitoshi,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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- Tandem cycloaddition-decarboxylation of α-keto acid and isocyanide under oxidant-free conditions towards monosubstituted oxazoles
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An efficient method, tandem [3 + 2] cycloaddition-decarboxylation of α-keto acid and isocyanide promoted by copper salt, has been developed. Under oxidant-free conditions, a series monosubstituted oxazoles have been constructed. Different from the traditional application of α-oxo acids as acyl surrogates, the elegant approach herein ingeniously avoids consuming excess oxidants.
- Zhang, Ling-Juan,Xu, Mei-Chen,Liu, Jie,Zhang, Xian-Ming
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- A solid-phase equivalent of van Leusen's TosMIC, and its application in oxazole synthesis
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Polystyrene-SH resin, prepared from Merrifield resin in two steps, was converted to polystyrene-SO2-CH2-NC in three steps. This resin functions as a solid-phase equivalent of p-tolylsulfonylmethyl isocyanide (TosMIC). Thus, reaction with aromatic aldehydes and tetrabutylammonium hydroxide as base yields 5-aryloxazoles.
- Kulkarni, Bheemashankar A.,Ganesan
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- Oxazole synthesis with minimal purification: Synthesis and application of a ROMPgel tosmic reagent
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equations presented The synthesis of ring opening metathesis, polymer-supported Tosmic reagent 1 is described. This reagent was utilized in the conversion of aldehydes to oxazoles in good yields and purities.
- Barrett, Anthony G. M.,Cramp, Susan M.,Hennessy, Alan J.,Procopiou, Panayiotis A.,Roberts, Richard S.
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- Improvement of the Van Leusen reaction in the presence of β-cyclodextrin: A green and efficient synthesis of oxazoles in water
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An efficient approach for the synthesis of oxazoles through the Van Leusen reaction in the presence of β-cyclodextrin is described. In aqueous medium using β-cyclodextrin as a supramolecular catalyst, tosylmethyl isocyanide was deprotonated by triethylami
- Rahimzadeh, Golnaz,Kianmehr, Ebrahim,Mahdavi, Mohammad
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- Heterocyclizations via TosMIC-based multicomponent reactions: A new approach to one-pot facile synthesis of substituted quinoxaline derivatives
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A novel multicomponent reaction involving o-phenylenediamines, aldehydes and p-toluenesulfonylmethyl isocyanide (TosMIC) in the presence of a base leading to the formation of quinoxalines in very good yields is described. Georg Thieme Verlag Stuttgart.
- Neochoritis, Constantinos,Stephanidou-Stephanatou, Julia,Tsoleridis, Constantinos A.
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- Cobalt-catalyzed arylation of azole heteroarenes via direct C-H bond functionalization
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(Equation presented) We herein report a new cobalt-catalyzed method for arylation of azole heteroarenes, including thiazole, oxazole, imidazole, benzothiazole, benzoxazole, and benzimidazole. The direct arylation of thiazole and oxazole was achieved both with iodo- and bromoarenes as the aryl donors in the presence of cobalt catalyst [Co(OAc)2/IMes] and cesium carbonate, while imidazole required the use of zinc oxide as the base. A complete reversal of arylation from C-5 to C-2 was accomplished using the bimetallic Co/Cu/IMes system. A direct comparison of the new cobalt method and the previously developed palladium protocol revealed significant differences, in terms of both chemical yield and selectivity.
- Sezen, Bengue,Sames, Dalibor
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- Synthesis and biological activity of 5-(4-methoxyphenyl)-oxazole derivatives
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5-(4′-Methoxyphenyl)-oxazole (MPO), originally reported as a synthetic compound, was isolated from fungal culture broth as an inhibitor of hatch and growth of Caenorhabditis elegans. Nineteen MPO derivatives were chemically synthesized, but showed no effect on C. elegans hatch and growth. These findings strongly suggested that the whole structure of MPO is essential for anti-C. elegans activity.
- Yamamuro, Daisuke,Uchida, Ryuji,Ohtawa, Masaki,Arima, Shiho,Futamura, Yushi,Katane, Masumi,Homma, Hiroshi,Nagamitsu, Tohru,Osada, Hiroyuki,Tomoda, Hiroshi
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- An efficient two-step synthesis of 2,5-disubstituted oxazole derivatives involving cu-promoted carbon-carbon single bond formation
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Environment sensitive fluorescence probe to detect various organelles is emerging as an excellent tool to attract the attention of a large number of researchers around the globe. The recent developments have shown that oxazole dyes are very competent and can exhibit a useful fluorescence property in this direction. An efficient synthetic procedure towards 2,5-diaryl substituted oxazole derivatives have been reported. It is a two-step technique involving classical van Leusen protocol followed by copper-mediated coupling with aryl halides to introduce the required carbon-carbon single bond. The aryl groups are chosen in such a way so that the aryl functionalities at 2- and 5-positions of oxazole can act as acceptor and donor moiety respectively. Thus, in turn, the extended conjugation from donor moiety to acceptor moiety via the oxazole ring is set up therein. The oxazole derivatives were characterized by various spectroscopic measurements like NMR, IR and MS.
- Maiti, Jyotirmay,Biswas, Suman,Das, Ranjan
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- Oxazole Synthesis by Sequential Asmic-Ester Condensations and Sulfanyl-Lithium Exchange-Trapping
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Oxazoles are rapidly assembled through a sequential deprotonation-condensation of Asmic, anisylsulfanylmethylisocyanide, with esters followed by sulfanyl-lithium exchange-trapping. Deprotonating Asmic affords a metalated isocyanide that efficiently traps esters to afford oxazoles bearing a versatile C-4 anisylsulfanyl substituent. Interchange of the anisylsulfanyl substituent is readily achieved through a first-in-class sulfur-lithium exchange-electrophilic trapping sequence whose versatility is illustrated in the three-step synthesis of the bioactive natural product streptochlorin.
- Mueller, Louis G.,Chao, Allen,Alwedi, Embarek,Natrajan, Maanasa,Fleming, Fraser F.
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p. 1500 - 1503
(2021/03/08)
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- Azole-Based Indoleamine 2,3-Dioxygenase 1 (IDO1) Inhibitors
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The heme enzyme indoleamine 2,3-dioxygenase 1 (IDO1) plays an essential role in immunity, neuronal function, and aging through catalysis of the rate-limiting step in the kynurenine pathway of tryptophan metabolism. Many IDO1 inhibitors with different chemotypes have been developed, mainly targeted for use in anti-cancer immunotherapy. Lead optimization of direct heme iron-binding inhibitors has proven difficult due to the remarkable selectivity and sensitivity of the heme-ligand interactions. Here, we present experimental data for a set of closely related small azole compounds with more than 4 orders of magnitude differences in their inhibitory activities, ranging from millimolar to nanomolar levels. We investigate and rationalize their activities based on structural data, molecular dynamics simulations, and density functional theory calculations. Our results not only expand the presently known four confirmed chemotypes of sub-micromolar heme binding IDO1 inhibitors by two additional scaffolds but also provide a model to predict the activities of novel scaffolds.
- R?hrig, Ute F.,Majjigapu, Somi Reddy,Reynaud, Aline,Pojer, Florence,Dilek, Nahzli,Reichenbach, Patrick,Ascencao, Kelly,Irving, Melita,Coukos, George,Vogel, Pierre,Michielin, Olivier,Zoete, Vincent
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p. 2205 - 2227
(2021/03/01)
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- Design, synthesis and biological evaluation of imidazole and oxazole fragments as HIV-1 integrase-LEDGF/p75 disruptors and inhibitors of microbial pathogens
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We describe here the synthesis of libraries of novel 1-subtituted-5-aryl-1H-imidazole, 5-aryl-4-tosyl-4,5-dihydro-1,3-oxazole and 5-aryl-1,3-oxazole fragments via microwave (MW)-assisted cycloaddition of para-toluenesulfonylmethyl isocyanide (TosMIC) to imines and aldehydes. The compounds obtained were biologically evaluated in an AlphaScreen HIV-1 IN-LEDGF/p75 inhibition assay with six imidazole-based compounds (16c, 16f, 17c, 17f, 20a and 20d) displaying more than 50% inhibition at 10 μM, with IC50 values ranging from 7.0 to 30.4 μM. Additionally the hypothesis model developed predicts all active scaffolds except 20d to occupy similar areas as the N-heterocyclic (A) moiety and two aromatic rings (B and C) of previously identified inhibitor 5. These results indicate that the identified compounds represent a viable starting point for their use as templates in the design of next generation inhibitors targeting the HIV-1 IN and LEDGF/p75 protein-protein interaction. In addition, the in vitro antimicrobial properties of these fragments were tested by minimum inhibitory concentration (MIC) assays showing that compound 16f exhibited a MIC value of 15.6 μg/ml against S. aureus, while 17f displayed a similar MIC value against B. cereus, suggesting that these compounds could be further developed to specifically target those microbial pathogens.
- Rashamuse, Thompho J.,Harrison, Angela T.,Mosebi, Salerwe,van Vuuren, Sandy,Coyanis, E. Mabel,Bode, Moira L.
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- Reaction Conditions for the Regiodivergent Direct Arylations at C2- or C5-Positions of Oxazoles using Phosphine-Free Palladium Catalysts
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Two sets of reaction conditions for the regiodivergent C2- or C5- direct arylations of oxazole are reported. In both cases, phosphine-free catalysts and inexpensive bases were employed allowing the access to the arylated oxazoles in moderate to high yields. Using Pd(OAc)2/KOAc as catalyst and base, regioselective C5-arylations were observed; whereas, using Pd(acac)2/Cs2CO3 system, the arylation occurred at the C2-position of oxazole. The higher reactivity of C5-H bond of oxazole as compared to the C2-H bond in the presence of Pd(OAc)2/KOAc system is consistent with a concerted metalation deprotonation mechanism; whereas the C2-arylation likely occurs via a simple base deprotonation of the oxazole C2-position. Then, from these C2- or C5-arylated oxazoles, a second palladium-catalyzed direct C?H bond arylation affords 2,5-diaryloxazoles with two different aryl groups. We also applied these sequential arylations to the straightforward synthesis of 2-arylphenanthro[9,10-d]oxazoles via three C?H bond functionalization steps. The Ru-catalyzed C?H arylation of the aryl unit of 2-aryloxazoles is also described. (Figure presented.).
- Shi, Xinzhe,Soulé, Jean-Fran?ois,Doucet, Henri
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p. 4748 - 4760
(2019/09/12)
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- Tandem oxidative isocyanide-based cycloaddition reactions in the presence of MIL-101(Cr) as a reusable solid catalyst
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The tandem oxidative three-component synthesis of two types of the heterocycles such as furans and imidazopyridines, via isocyanides [1+4] cycloaddition reactions in the presence of MIL-101(Cr) under aerobic conditions are reported. When the 4-toluenesulfonylmethyl isocyanide was used, an unexpected [3+2] cycloaddition reaction of isocyanides with aldehydes accomplished and dihydrophenyloxazoles and phenyloxazoles produced. These syntheses were successfully carried out using a wide scope of the substrates.
- Shaabani, Ahmad,Sepahvand, Heshmatollah,Amini, Mostafa M.,Hashemzadeh, Alireza,Borjian Boroujeni, Mahmoud,Badali, Elham
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p. 1832 - 1837
(2018/03/07)
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- URIDINE NUCLEOSIDE DERIVATIVES, COMPOSITIONS AND METHODS OF USE
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This disclosure relates to uridine nucleoside derivatives, compositions comprising therapeutically effective amounts of those nucleoside derivatives and methods of using those nucleoside derivatives or compositions in treating disorders that are responsive to compounds, such as agonists, of P2Y6 receptor, e.g., neuronal disorders, including neurodegenerative disorders (e.g., Alzheimer's disease, Parkinson's disease) and traumatic CNS injury, pain, Down Syndrome (DS), glaucoma and inflammatory conditions.
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Paragraph 0259
(2018/04/20)
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- A robust and efficient catalyst possessing an electron-deficient ligand for the palladium-catalyzed direct arylation of heteroarenes
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The exploration of the direct arylation capacity of a unique, thermally stable, and air-stable Pd0-phosphine catalyst is reported. Besides decisively contributing to catalyst robustness, the electron-deficient trifluoromethyl-substituted triphenylphosphine ligands make the palladium center more electron-deficient and accelerate the direct arylation step. The combination of only 0.5-2 mol-% of the catalyst and a substoichiometric quantity of pivalic acid generates an efficient system to promote biaryl-forming reactions of a broad range of electronically varied hetarenes and aryl bromides. The observed regioselective arylations suggest that a concerted metalation-deprotonation pathway is involved in the C-H activation step.
- Jakab, Alexandra,Dalicsek, Zoltn,Sos, Tibor
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supporting information
p. 56 - 59
(2015/02/19)
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- Nickel-catalyzed decarboxylative acylation of heteroarenes by sp 2 C-H functionalization
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Nickel-catalyzed ligand-free decarboxylative cross-coupling of azole derivatives with α-oxoglyoxylic acids has been developed. This work represents the first example of decarboxylative cross-coupling reactions, in a C-H bond functionalization manner, thro
- Yang, Ke,Zhang, Cheng,Wang, Peng,Zhang, Yan,Ge, Haibo
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supporting information
p. 7241 - 7244
(2014/06/23)
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- Nickel-catalyzed decarboxylative arylation of heteroarenes through sp2 C-H functionalization
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The direct decarboxylative arylation of hetereoarenes with benzoic acids through a nickel-catalyzed sp2 C-H functionalization process was developed. This process provides the first examples of decarboxylative cross-coupling reactions with aroma
- Yang, Ke,Wang, Peng,Zhang, Cheng,Kadi, Adnan A.,Fun, Hoong-Kun,Zhang, Yan,Lu, Hongjian
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supporting information
p. 7586 - 7589
(2015/04/22)
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- Copper-mediated C-H/C-H biaryl coupling of benzoic acid derivatives and 1,3-azoles
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Hot couple: A precious-metal-free copper-mediated intermolecular direct biaryl coupling of benzoic acid derivatives and 1,3-azoles has been developed. The key to success is the installation of an amide-based bidentate coordinating group, which is easily removed and transformed into the parent ester groups after the coupling reaction. Kinetic studies indicate that the rate-limiting step is the aromatic C-H bond cleavage of benzoic acid derivatives. Copyright
- Nishino, Mayuko,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information
p. 4457 - 4461
(2013/05/22)
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- Synthesis and evaluation of photophysical properties of Series of π-conjugated oxazole dyes
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Incorporation of π-conjugated spacers at the 2 or 5 position of a 2,5-disubstitutedaryloxazole led to new series of fluorescent dyes. They show emissions from visible to 700 nm along with significant Stokes shift up to 208 nm and a strong solvatochromic fluorescence. These compounds are easily accessible in one step through direct C-H bond functionalization.
- Mahuteau-Betzer, Florence,Piguel, Sandrine
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supporting information
p. 3188 - 3193
(2013/06/27)
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- Palladium-catalyzed direct arylation of N-heteroarenes with arylsulfonyl hydrazides
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Hydrazides applied: A palladium-catalyzed direct Ci-H arylation of heteroarenes, with arylsulfonyl hydrazides as the arylating reagents, has been developed (see scheme). The reaction is chemoselective, in that arylsulfonyl hydrazides containing halogen substituents can be employed without participation of the halogen substituent in the reaction. The method offers a straightforward approach to a variety of aryl-heteroaryl compounds. Copyright
- Liu, Bo,Li, Jian,Song, Feijie,You, Jingsong
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supporting information; experimental part
p. 10830 - 10833
(2012/09/22)
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- Copper-mediated and copper-catalyzed cross-coupling of indoles and 1,3-azoles: Double C-H activation
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A new bronze age: The described copper-mediated cross-coupling with double C-H activation can provide a convergent access to indole-containing biheteroaryls that are of high interest in pharmaceutical and medicinal chemistry. In this strategy an easily attachable and detachable 2-pyrimidyl directing group is used. Moreover, a variant that is catalytic in copper is achieved by using atmospheric oxygen as an ideal co-oxidant (see scheme). Copyright
- Nishino, Mayuko,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; experimental part
p. 6993 - 6997
(2012/10/07)
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- Copper-mediated intermolecular direct biaryl coupling
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Copper-mediated intermolecular direct biaryl coupling of arylazines and azoles via dual C-H bond cleavage proceeds even without palladium catalysts. The reaction system shows the high potential of copper salts in direct C-H arylation chemistry and provides a new approach to biaryl motifs, which are ubiquitous in pharmaceuticals and functional materials.
- Kitahara, Masanori,Umeda, Nobuyoshi,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; body text
p. 2160 - 2162
(2011/04/23)
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- Highly regioselective palladium-catalyzed direct arylation of oxazole at C-2 or C-5 with aryl bromides, chlorides, and triflates
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Complementary palladium-catalyzed methods for direct arylation of oxazole with high regioselectivity (>100:1) at both C-5 and C-2 have been developed for a wide range of aryl and heteroaryl bromides, chlorides, iodides, and triflates. C-5 arylation is pre
- Strotman, Neil A.,Chobanian, Harry R.,Guo, Yan,He, Jiafang,Wilson, Jonathan E.
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supporting information; experimental part
p. 3578 - 3581
(2010/11/04)
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- 1,1-dibromo-1-alkenes as valuable partners in the copper-catalyzed direct alkynylation of azoles
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The copper-catalyzed direct alkynylation of azoles with 1,1-dibromo-1-alkenes as electrophiles is described. These easily accessible substrates are a useful addition to the field of direct alkynylations in an efficient and functional group tolerant reaction to provide a straightforward entry to diverse alkynyl heterocycles.
- Pacheco Berciano, Beatriz,Lebrequier, Sabrina,Besselievre, Francois,Piguel, Sandrine
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supporting information; experimental part
p. 4038 - 4041
(2010/11/16)
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- A Mild and convenient synthesis of 4-tosyl-4,5-dihydrooxazoles
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A facile and mild synthesis of 4-tosyl-4,5-dihydrooxazoles is described. The reaction between tosyl methyl isocyanide (TosMIC) and cinnamic or aromatic aldehydes is catalyzed by triethylamine, affording trans-5-styryl- or 5-aryl-4-tosyl-4,5-dihydrooxazole
- Companyo, Xavier,Moyano, Albert,Rios, Ramon
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experimental part
p. 293 - 296
(2010/04/23)
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- Synthesis of 2,5-diaryloxazoles through van Leusen reaction and copper-mediated direct arylation
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The direct arylation of 5-aryloxazoles, prepared by the van Leusen reaction, with various aryl iodides is effectively promoted by a system of CuI combined with PPh3 and Na2CO3 as a ligand and a base, respectively, in DMF to produce the corresponding 2,5-diaryloxazoles in good yields.
- Yoshizumi, Tomoki,Satoh, Tetsuya,Hirano, Koji,Matsuo, Daisuke,Orita, Akihiro,Otera, Junzo,Miura, Masahiro
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supporting information; body text
p. 3273 - 3276
(2009/08/09)
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- Ligandless microwave-assisted Pd/Cu-catalyzed direct arylation of oxazoles
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(Chemical Equation Presented) An efficient microwave-assisted palladium/copper co-mediated direct arylation of oxazoles with aryl bromides under ligandless conditions has been developed. The method is functional group tolerant and provides rapid access to medicinally relevant compounds in good yields. Coupled to the van Leusen oxazole ring synthesis, this methodology is illustrated by an expedient two-step synthesis of the four 2,5-diaryloxazole alkaloids texamine, texaline, balsoxin, and O-Me-halfordinol from commercially available starting materials.
- Besselievre, Francois,Mahuteau-Betzer, Florence,Grierson, David S.,Piguel, Sandrine
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p. 3278 - 3280
(2008/09/19)
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- Stereoselective direct copper-catalyzed alkenylation of oxazoles with bromoalkenes
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(Chemical Equation Presented) A copper-catalyzed direct alkenylation of oxazoles with bromoalkenes has been developed. The method is both regio- and stereoselective and tolerates a variety of functional groups. A wide range of 2-E-vinyl-substituted oxazoles were obtained in high yields including the highly fluorescent alkaloid annuloline.
- Besselievre, Francois,Piguel, Sandrine,Mahuteau-Betzer, Florence,Grierson, David S.
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body text
p. 4029 - 4032
(2009/06/18)
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- A domino copper-catalyzed C-N and C-O cross-coupling for the conversion of primary amides into oxazoles
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A variety of oxazoles can efficiently be prepared, in a single step and in good yield, from primary amides and 1,2-dihaloalkenes using copper-catalysis. This new method allows the regioselective formation of a range of substituted oxazoles. The required 1,2-dihaloalkenes can prepared by simple treatment of alkynes with elemental bromine or iodine. Georg Thieme Verlag Stuttgart.
- Schuh, Kerstin,Glorius, Frank
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p. 2297 - 2306
(2008/02/13)
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- Reactions between weinreb amides and 2-magnesiated oxazoles: A simple and efficient preparation of 2-acyl oxazoles
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(Chemical Equation Presented) Treatment of oxazole or 5-aryl oxazoles with i-PrMgCl smoothly generates the corresponding 2-Grignard reagents, which react with Weinreb amides to provide exclusively 2-acyl oxazole products.
- Pippel, Daniel J.,Mapes, Christopher M.,Mani, Neelakandha S.
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p. 5828 - 5831
(2008/02/09)
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- Photochemistry of 4- and 5- phenyl substituted isoxazoles
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5-Phenylisoxazole (4) and 4-phenylisoxazole (22) underwent phototransposition to 5-phenyloxazole (5) and 4-phenyloxazole (24) respectively. Labeling with deuterium or methyl confirmed that these phototrans-positions occurred via the P4 pathway which involves only interchange of the N2 and C3 ring position. Thus, 4-deuterio-5-phenylisoxazole (4-4d), 4-methyl-5-phenylisoxazole (10), and 5-methyl-4-phenylisoxazole (23) phototransposed to 4-deuterio-5-phenyloxazole (5-4d), 4-methyl-5-phenyloxazole (11), and 5-methyl-4-phenyloxazole (25) respectively. In addition to phototransposition, isoxazoles 4, 10, and 23 also underwent photo-ring cleavage to yield benzoylacetonitrile (9), α-benzoylpropionitrile (15), and aceto-α-phenyl-acetonitrile (26) respectively. Irradiation of 5-phenyl-3-(trifluoromethyl)isoxazole (16) in acetonitrile led to 5-phenyl-2-(trifluoromethyl)oxazole (17), the P4 phototransposition product. Irradiation of 16 in methanol led to a substantial decrease in the yield of 17 and to the formation of a mixture of (E) and (Z)-2-methoxy-2- (trifluoromethyl)-3-benzoylaziridines 18a and 18b.
- Pavlik, James W.,St. Martin, Heather,Lambert, Karen A.,Lowell, Jennifer A.,Tsefrikas, Vikki M.,Eddins, Cheryl K.,Kebede, Naod
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p. 273 - 281
(2007/10/03)
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- New routes to 5-substituted oxazoles
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Ultrasound-promoted desulfonylation of 5-substituted 4-tosyloxazoles, prepared from tosylmethyl isocyanide and carboxylic acid chlorides or by dianion chemistry, leads to 5-monosubstituted oxazoles. The Royal Society of Chemistry 2000.
- Addie, Matthew S.,Taylor, Richard J.K.
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p. 527 - 531
(2007/10/03)
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- Substituted biphenyl isoxazole sulfonamides
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Compounds of the formula STR1 inhibit the activity of endothelin. The symbols are defined as follows: R1, R2, R3 and R4 are each directly bonded to a ring carbon and are each independently (a) hydrogen; (b) alkyl, alkenyl, alkynyl, alkoxy, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, aryloxy, aralkyl or aralkoxy, any of which may be substituted with Z1, Z2 and Z3 ; (c) halo; (d) hydroxyl; (e) cyano; (f) nitro; (g) --C(O)H or --C(O)R5 ; (h) --CO2 H or --CO2 R5 ; (i) --Z4 --NR6 R7 ; (j) --Z4 --N(R10)--Z5 --NR8 R9 ; or (k) R3 and R4 together may also be alkylene or alkenylene, either of which may be substituted with Z1, Z2 and Z3, completing a 4- to 8-membered saturated, unsaturated or aromatic ring together with the carbon atoms to which they are attached; and the remaining symbols are as defined in the specification.
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- PYROLYSE-ECLAIR SOUS VIDE DE 1,2,4-TRIAZOLIDES = UNE ETUDE PAR SPECTROMETRIE DE MASSE EN TANDEM
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A real-time analysis of the flash-vacuum pyrolysis products of some 1,2,4-triazolides has been performed by tandem mass spectrometry.Beside decay products, ketenes and the parent 1,2,4-triazole, 1-acyltriazoles give rise to 5-alkyloxazoles and nitrogen.This ring transformation reaction implies a sigmatropic shift of the acyl group from nitrogen to carbon, loss of nitrogen and cyclisation of the biradical intermediate. 5-aryloxazoles are similarly obtained from 1-aroyltriazoles.
- Maquestiau, A.,Puk, E.,Flammang, R.
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p. 181 - 190
(2007/10/02)
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- Synthesis of arylsulfonimidoyl fluorides and their use in the preparation of (arylsulfonimidoyl)methyl isocyanides. Partial resolution of optically active S-phenyl-N-tosylsulfonimidoyl fluoride
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N-Tosyl- and N-methyl-substituted sulfonimidoyl fluorides (2) have been synthesized from the corresponding chlorides by displacement with fluoride ion.S-Phenyl-N-tosylsulfonimidoyl fluoride (2a) is a stable (persistent) shelf compound, which has been used
- Leusen, Daan van,Leusen, Albert M. van
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