- An efficient synthesis of benzoxazoles using silica-supported tin exchanged silicotungstic acid catalyst
-
An efficient method for the preparation of benzoxazoles by reacting aminophenols with orthoesters in the presence of silica-supported tin exchanged silicotungstic acid catalyst under mild conditions with high yield and selectivity is demonstrated. The catalysts were characterized by FT-IR and pyridine adsorbed FT-IR. The catalyst exhibited consistent activity upon recycling and is highly active compared to other catalysts. The role of Lewis acidity of the catalysts and plausible reaction mechanism is presented.
- Srivani,Venkateswar Rao,Sai Prasad,Lingaiah
-
-
Read Online
- Visible Light-Induced Copper-Catalyzed C—H Arylation of Benzoxazoles?
-
A general method for visible light-induced copper-catalyzed arylation of sp2 C—H bonds of azoles has been developed. The method employs aryl halide as the coupling partner, lithium alkoxide as base. A variety of azoles including benzooxazole and benzothiazole can be arylated. Furthermore, electron-poor heterocycles such as thiophene possessing one electron-withdrawing group can also be arylated.
- Ma, Xiaodong,Zhang, Guozhu
-
supporting information
p. 1299 - 1303
(2020/08/05)
-
- Room-temperature palladium-catalyzed direct 2-alkenylation of azole derivatives with alkenyl bromides
-
Pd-catalyzed direct C2-alkenylation of azole derivatives proceeds efficiently under mild conditions, and the reaction of substituted benzoxazoles, oxazole and benzothiazole occurred even at room temperature. The substrate scope of the reaction was turned out to include mono-, di- and trisubstituted alkenyl bromides. To validate the scalability of this method, 5-Methyl-2-(prop-1-en-2-yl)benzoxazole (3c) was prepared on one-gram scale at room temperature.
- Yao, Yun-Xin,Fang, Dong-Mei,Gao, Feng,Liang, Xiao-Xia
-
supporting information
p. 68 - 71
(2018/12/05)
-
- Cu-Catalyzed Direct C-P Bond Formation through Dehydrogenative Cross-Coupling Reactions between Azoles and Dialkyl Phosphites
-
A direct dehydrogenative cross-coupling of azoles [C(sp2)-H] with dialkyl phosphites [P(O)-H] to access 2-phosphonated azoles using Cu(I)/Cu(II) as catalyst and K2S2O8/di-tert-butylperoxide as oxidant has been achieved. A remarkable advantage over reported procedures includes that oxazoles, imidazoles, benz(ox/othi/imid)azoles, and indole are found to react under optimized reaction conditions to provide corresponding adducts in high yields. The mechanistic insight of cross-coupling was obtained by deuterium kinetic isotope effect studies.
- Hore, Soumyadip,Srivastava, Abhijeet,Singh, Ravi P.
-
p. 6868 - 6878
(2019/06/14)
-
- Method for synthesizing benzoxazole through microwave radiation of benzamide compound in water phase
-
The invention discloses a method for synthesizing benzoxazole through microwave radiation of a benzamide compound in a water phase. The benzamide compound is added into the water phase under the microwave condition to be subjected to a cyclization reaction for generating the benzoxazole under the alkali condition, and the method for preparing the benzoxazole is environmentally friendly, easy and convenient to operate, safe, low in cost and efficient. Compared with the prior art, the method can be applied to a large number of functional groups, the yield is high, the number of by-products is small, and the method is easy to operate, safe, low in cost and environmentally friendly. (Please see the specifications for the formula).
- -
-
Paragraph 0072
(2019/03/08)
-
- Cobalt-Catalyzed Cross-Dehydrogenative Coupling Reactions of (Benz)oxazoles with Ethers
-
The cobalt-catalyzed cross-dehydrogenative coupling of (benz)oxazoles and ethers is described. Access to some important bioactive heteroaryl ether derivatives was achieved using CoCO3 as an inexpensive catalyst at levels as low as 1.0 mol %. In
- Li, Yanrong,Wang, Mengshi,Fan, Wei,Qian, Fen,Li, Guigen,Lu, Hongjian
-
p. 11743 - 11750
(2016/12/09)
-
- PROCESS FOR THE PREPARATION OF SUVOREXANT AND INTERMEDIATES USEFUL IN THE SYNTHESIS OF SUVOREXANT
-
A novel processes for the preparation of suvorexant (formula I), its related compounds and its intermediates that are simple, economical and commercially viable. (I)
- -
-
Paragraph 0118-0119
(2016/07/05)
-
- Process for the preparation of an intermediate for an orexin receptor antagonist
-
The present invention is directed to processes for preparing an intermediate for a diazepane compound which is an antagonist of orexin receptors, and which is useful in the treatment or prevention of neurological and psychiatric disorders and diseases in which orexin receptors are involved.
- -
-
Paragraph 10; 11
(2017/02/02)
-
- Copper-catalyzed oxidative decarboxylative C-H arylation of benzoxazoles with 2-nitrobenzoic acids
-
A copper-catalyzed oxidative decarboxylative coupling of benzoxazoles with 2-nitrobenzoic acids was developed. This methodology favors electron-rich benzoxazoles and electron-deficient benzoic acids and enables the preparation of a variety of arylated benzoxazoles in good yields. The trends in product yields suggest a delicate balance between the decarboxylation and C-H arylation steps.
- Chen, Lijun,Ju, Lin,Bustin, Katelyn A.,Hoover, Jessica M.
-
supporting information
p. 15059 - 15062
(2015/10/12)
-
- Direct C-H iodination of 1,3-azoles catalysed by CuBr2
-
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
-
supporting information
p. 511 - 513
(2015/02/19)
-
- Room-temperature palladium-catalyzed direct 2-arylation of benzoxazoles with aryl and heteroaryl bromides
-
An efficient room-temperature palladium-catalyzed direct 2-arylation of benzoxazoles with aryl bromides is presented. The Pd(OAc)2/ NiXantphos-based catalyst enables the introduction of various aryl and heteroaryl groups, via a deprotonative cross-coupling process (DCCP) in good to excellent yields (60-99%). This journal is the Partner Organisations 2014.
- Gao, Feng,Kim, Byeong-Seon,Walsh, Patrick J.
-
supporting information
p. 10661 - 10664
(2014/10/15)
-
- Application of nano SnO2 as a green and recyclable catalyst for the synthesis of 2-aryl or alkylbenzoxazole derivatives under ambient temperature
-
Application of nano SnO2 as an efficient and benign catalyst has been explored for the synthesis of 2-aryl or alkylbenzoxazole derivatives via condensation reaction of aldehyde with 2-aminophenol. The reactions proceed under heterogeneous and mild conditions in ethanol at room temperature to provide 2-aryl or alkylbenzoxazoles in high yields.
- Vahdat, Seyed Mohammad,Raz, Shima Ghafouri,Baghery, Saeed
-
p. 579 - 585
(2014/07/07)
-
- Tungstate sulfuric acid as an efficient catalyst for the synthesis of benzoxazoles and benzothiazoles under solvent-free conditions
-
Tungstate sulfuric acid (TSA) has been found to be an efficient and reusable catalyst for the synthesis of benzoxazole and benzothiazole derivatives via reactions of orthoesters with o-aminophenols or o-aminothiophenols in high yields.
- Farahi, Mahnaz,Karami, Bahador,Azari, Masume
-
p. 1029 - 1034
(2013/11/06)
-
- A green and efficient protocol for the synthesis of quinoxaline, benzoxazole and benzimidazole derivatives using heteropolyanion-based ionic liquids: As a recyclable solid catalyst
-
In this paper, we introduce two nonconventional ionic liquid compounds which are composed of propane sulfonate functionalized organic cations and heteropolyanions as green solid acid catalysts for the highly efficient and green synthesis of 2,3-disubstitutedquinoxaline derivatives. These ionic liquids are in the solid state at room temperature and the synthesis is carried out via the one-pot condensation reaction of various o-phenylenediamine with 1,2-diketone derivatives. Benzoxazole and benzimidazole derivatives were also synthesized by these novel catalysts via the one-pot condensation from reaction orthoester with o-aminophenol (synthesis of benzoxazole derivatives) and ophenylenediamine (synthesis of benzimidazole derivatives). All experiments successfully resulted in the desired products. The described novel synthesis method has several advantages of safety, mild condition, high yields, short reaction times, simplicity and easy workup compared to the traditional method of synthesis.
- Vahdat, Seyed Mohammad,Baghery, Saeed
-
p. 618 - 627
(2013/09/12)
-
- Copper-mediated C-H/C-H biaryl coupling of benzoic acid derivatives and 1,3-azoles
-
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
-
supporting information
p. 4457 - 4461
(2013/05/22)
-
- Room-temperature copper-catalyzed oxidation of electron-deficient arenes and heteroarenes using air
-
No pressure: The oxidation of aromatic C-H bonds at room temperature was realized through a copper-catalyzed "oxygenase-type" oxidation of arenes and heteroarenes in the presence of air (see scheme). The reaction involves an oxygen-atom transfer from O2 in the air onto the substrates. Copyright
- Liu, Qiang,Wu, Pan,Yang, Yuhong,Zeng, Ziqi,Liu, Jie,Yi, Hong,Lei, Aiwen
-
supporting information; experimental part
p. 4666 - 4670
(2012/06/30)
-
- Direct arylation of benzoxazole C-H bonds with iodobenzene diacetates
-
A Pd (OAc)2-catalyzed direct arylation of benzoxazole C-H bonds has been achieved with iodobenzene diacetates as the arylation reagent in moderate to good yields. The procedure tolerates a series of functional groups, such as methoxy, nitro, cyano, chloro, and bromo groups.
- Yu, Peng,Zhang, Guangyou,Chen, Fan,Cheng, Jiang
-
supporting information; experimental part
p. 4588 - 4590
(2012/09/22)
-
- Nickel-catalyzed C-H direct amination of benzoxazoles with secondary amines
-
In this article, a facile, efficient and practical method for Ni-catalyzed direct C-H amination of benzoxazole with secondary amines has been developed. This procedure requires Ni(OAc)2·4H2O as catalyst, TBHP as oxidant and acid as the additive. A variety of substituted benzoxazol-2-amines were synthesized in moderate to good yields.
- Li, Yaming,Liu, Jin,Xie, Yusheng,Zhang, Rong,Jin, Kun,Wang, Xiuna,Duan, Chunying
-
supporting information; experimental part
p. 3715 - 3720
(2012/05/21)
-
- Palladium-catalyzed direct phosphonation of azoles with dialkyl phosphites
-
The first Pd-catalyzed direct phosphonation of azoles with dialkyl phosphites has been achieved without addition of base or acid. This method involves the oxidative cleavage of C-H and P(O)-H bonds and represents an atom-efficiency alternative to the classical phosphonation of Ar-X. A Pd II/PdIV mechanism has been studied and proposed.
- Hou, Chaodong,Ren, Yunlai,Lang, Rui,Hu, Xiaoxue,Xia, Chungu,Li, Fuwei
-
supporting information; experimental part
p. 5181 - 5183
(2012/06/01)
-
- Copper-mediated and copper-catalyzed cross-coupling of indoles and 1,3-azoles: Double C-H activation
-
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
-
supporting information; experimental part
p. 6993 - 6997
(2012/10/07)
-
- Enantioselective synthesis of a dual orexin receptor antagonist
-
A concise, enantioselective synthesis of the potent dual orexin inhibitor suvorexant (1) is reported. Key features of the synthesis include a mild copper-catalyzed amination, a highly chemoselective conjugate addition, and a tandem enantioselective transamination/seven-membered ring annulation. The synthesis requires inexpensive starting materials and only four linear steps for completion.
- Mangion, Ian K.,Sherry, Benjamin D.,Yin, Jingjun,Fleitz, Fred J.
-
supporting information; experimental part
p. 3458 - 3461
(2012/08/08)
-
- PROCESS FOR THE PREPARATION OF AN OREXIN RECEPTOR ANTAGONIST
-
The present invention is directed to processes for preparing a diazepane compound which is an antagonist of orexin receptors, and which is useful in the treatment or prevention of neurological and psychiatric disorders and diseases in which orexin receptors are involved. The present invention is further directed to crystalline forms of this diazepane compound and pharmaceutical compositions thereof.
- -
-
Page/Page column 39-40
(2012/11/13)
-
- 1,3-Dibromo-5,5-dimethylhydantoin as an efficient homogeneous catalyst for synthesis of benzoxazoles, benzimidazoles, and oxazolo[4,5-b]pyridines
-
A simple and highly efficient method for synthesis of benzoxazoles, benzimidazoles, and oxazolo[4,5-b]pyridines is described. Condensation of orthoesters with o-substituted anilines or 2-amino-3-hydroxypyridine was performed in the presence of catalytic amounts of commercially available, inexpensive, and moisture-stable 1,3-dibromo-5,5-dimethylhydantoin under solvent-free conditions. The corresponding heterocycles were obtained in good to excellent yields. The main advantages of the present procedure are mild reaction conditions, short reaction times, high yields of products, easy work-up, and absence of solvent. Graphical abstract: [Figure not available: see fulltext.]
- Hojati, Seyedeh Fatemeh,Maleki, Behrooz,Beykzadeh, Zahra
-
experimental part
p. 87 - 91
(2011/09/19)
-
- Copper-catalyzed oxidative amination of benzoxazoles via C-H and C-N bond activation: A new strategy for using tertiary amines as nitrogen group sources
-
An efficient and conceptually new method for oxidative amination of azoles with tertiary amines via copper-catalyzed C-H and C-N bond activation has been developed. This protocol can be performed in the absence of external base and only requires atmospheric oxygen as oxidant. The catalyst system is very simple and efficient, which opens a new way for using tertiary amines as nitrogen group sources for C-N bond formation reactions.
- Guo, Shengmei,Qian, Bo,Xie, Yinjun,Xia, Chungu,Huang, Hanmin
-
experimental part
p. 522 - 525
(2011/04/18)
-
- Amination of benzoxazoles and 1,3,4-oxadiazoles using 2,2,6,6- tetramethylpiperidine-N-oxoammonium tetrafluoroborate as an organic oxidant
-
No transition metals are necessary to convert benzoxazoles and 1,3,4-oxadiazoles into the corresponding pharmacologically interesting 2-aminated heterocycles by formal direct C(2)-amination using tetramethylpiperidine-N-oxoammonium tetrafluoroborate (TEMPO+BF 4-) as an oxidant (see scheme; TEMP=2,2,6,6- tetramethylpiperidine; TfOH=trifluoromethanesulfonic acid).
- Wertz, Sebastian,Kodama, Shintaro,Studer, Armido
-
supporting information; experimental part
p. 11511 - 11515
(2012/01/11)
-
- Copper-catalyzed direct oxidative C-H amination of benzoxazoles with formamides or secondary amines under mild conditions
-
A facile, efficient, and practical method for copper-catalyzed direct C-H amination of benzoxazoles with formamides or secondary amines has been developed. The system can be performed in the absence of external base and only requires O2 or even air as oxidant. A variety of substituted benzoxazol-2-amines were synthesized with moderate to excellent yield.
- Li, Yaming,Xie, Yusheng,Zhang, Rong,Jin, Kun,Wang, Xiuna,Duan, Chunying
-
supporting information; experimental part
p. 5444 - 5449
(2011/08/06)
-
- Palladium-catalyzed desulfitative C-arylation of a benzo[d]oxazole C-H bond with arene sulfonyl chlorides
-
A palladium-catalyzed direct desulfitative C-arylation of a benzo[d]oxazole C-H bond with arene sulfonyl chlorides is described. The procedure tolerates halo, cyano, nitro, trifluoromethyl, acetyl and acetylamino groups on the phenyl ring of sulfonyl chlorides, providing the arylation products in moderate to good yields. It represents a practical and attractive alternative for the synthesis of 2-aryl benzoxazoles.
- Zhang, Manli,Zhang, Shouhui,Liu, Miaochang,Cheng, Jiang
-
supporting information; experimental part
p. 11522 - 11524
(2011/11/12)
-
- Carbon dioxide as the C1 source for direct C-H functionalization of aromatic heterocycles
-
(Equation Presented). A simple and straightforward method has been developed for the direct carboxylation of aromatic heterocylces such as oxazoles, thiazoles, and oxadiazoles using CO2 as the C1 source. The reactions require no metal catalyst and only Cs2CO3 as the base. A good functional group tolerance is achieved.
- Vechorkin, Oleg,Hirt, Nathalie,Hu, Xile
-
supporting information; experimental part
p. 3567 - 3569
(2010/10/02)
-
- Mild and efficient synthesis of benzoxazoles, benzothiazoles, benzimidazoles, and oxazolo[4,5-b]pyridines catalyzed by Bi(III) salts under solvent-free conditions
-
A series of benzoxazoles, benzothiazoles, benzimidazoles, and oxazolo[4,5-b]pyridines was efficiently synthesized from the reactions of o-aminophenols, o-aminothiophenol, o-phenylenediamines, and 2-amino-3- hydroxypyridine with orthoesters in the presence of catalytic amounts of Bi(III) salts, such as Bi(TFA)3, Bi(OTf)3, and BiOClO4 ? xH2O under solvent-free conditions. The remarkable features of this new protocol are high conversion, very short reaction times, cleaner reaction profiles under solvent-free conditions, straightforward procedure, and use of relatively non-toxic catalysts. Springer-Verlag 2007.
- Mohammadpoor-Baltork, Iraj,Khosropour, Ahmad R.,Hojati, Seyedeh F.
-
p. 663 - 667
(2008/02/07)
-
- Deamination of 2-aminothiazoles and 3-amino-1,2,4-triazines with nitric oxide in the presence of a catalytic amount of oxygen
-
2-Aminothiazoles, 2-aminobenzazoles, and 3-amino-1,2,4-triazines were deaminated using nitric oxide (NO) in the presence of a catalytic amount of oxygen to afford corresponding unsubstituted heterocycles in good yields.
- Itoh, Takashi,Matsuya, Yuji,Nagata, Kazuhiro,Ohsawa, Akio
-
p. 1547 - 1549
(2007/10/03)
-