- Visible Light-Promoted Aryl Azoline Formation over Mesoporous Organosilica as Heterogeneous Photocatalyst
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N-heterocyclic compounds demonstrate wide applications ranging from natural compound production to coordination chemistry. Usually, the synthesis of N-heterocyclic compounds is conducted under thermal conditions, mostly by Lewis acids or metal-containing compounds as molecular catalysts. Here, we report a photocatalytic route for aryl azoline formation by mesoporous organosilica as visible light-active and heterogeneous photocatalyst. Via formation of aromatic aldehydes with various amines, 2-phenyl-2-imidazoline, 2-phenyl-2-oxazoline, 2-phenyl-2-thiazoline and their derivatives could be formed with high conversion and selectivity. Additionally, the organosilica photocatalyst showed high stability and reusability.
- Wei, Wenxin,Li, Run,Huber, Niklas,Kizilsavas, G?nül,Ferguson, Calum T. J.,Landfester, Katharina,Zhang, Kai A. I.
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p. 3410 - 3413
(2021/05/29)
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- The Elusive Seven-Membered Cyclic Imino Ether Tetrahydrooxazepine
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Cyclic imino ether heterocycles are used as ligands in transition metal catalysis, in various drugs and as reactive monomers in living cationic ring-opening polymerization (CROP). While five- and six-membered cyclic imino ethers, i.e. 2-oxazolines and 4,5-dihydro-1,3-oxazines, have extensively been studied in these areas, their seven-membered ring counterparts have remained unexplored. Herein, we report the synthesis of 2-phenyl-4,5,6,7-tetrahydro-1,3-oxazepine allowing reassignment of the earlier, incorrectly reported 4,5,6,7-tetrahydro-1,3-oxazepines as their N-acylated pyrrolidine isomers. Finally, we also report a comparison of the CROP reactivity of a homologous series of cyclic imino ethers with a 2-carbon, 3-carbon, and 4-carbon methylene bridge, revealing a remarkable ring size effect.
- Verbraeken, Bart,Hullaert, Jan,Van Guyse, Joachim,Van Hecke, Kristof,Winne, Johan,Hoogenboom, Richard
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supporting information
p. 17404 - 17408
(2019/01/04)
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- A 2 - substituted oxazoline or 2 - substituted piperazine synthetic method (by machine translation)
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The invention discloses a method for synthesizing 2 - substituted oxazoline or 2 - substituted oxazine new method, by nitrile and amino ethanol or 3 - amino - 1 - propanol as raw material, in the absence of solvent, can be used for the recycling of the sulfur to induce synthesis of 2 - substituted oxazoline and 2 - substituted piperazine. The method of the invention has low cost, simple reaction process, mild reaction conditions, the reaction time is short, the yield and the like, is suitable for the industrial generation. (by machine translation)
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Paragraph 0040; 0041; 0049
(2017/08/25)
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- Highly efficient synthesis of β-nitrate ester carboxamides through the ring-opening of 2-oxazolines
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A novel method for the synthesis of β-nitrate ester carboxamides using non-corrosive tert-butyl nitrite (TBN) as the nitro source and easily available oxygen as the oxidant has been developed. Variously substituted 2-oxazolines were efficiently ring-opened to deliver the corresponding products in excellent yields. Notably, this reaction provides fast access to pharmaceuticals such as nicorandil.
- Qiao, Kai,Yuan, Xin,Wan, Li,Zheng, Ming-Wei,Zhang, Dong,Fan, Bing-Bing,Di, Zhe-Chen,Fang, Zheng,Guo, Kai
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supporting information
p. 5789 - 5793
(2017/12/26)
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- Microwave-Assisted Synthesis of 2-Aryl-2-oxazolines, 5,6-Dihydro-4H-1,3-oxazines, and 4,5,6,7-Tetrahydro-1,3-oxazepines
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The first general procedure for the synthesis of 5- to 7-membered cyclic iminoethers by microwave-assisted cyclization of ω-amido alcohols promoted by polyphosphoric acid (PPA) esters is presented. 2-Aryl-2-oxazolines and 5,6-dihydro-4H-1,3-oxazines were efficiently prepared using ethyl polyphosphate/CHCl3. Trimethylsilyl polyphosphate in solvent-free conditions allowed for the synthesis of hitherto-unreported 4,5,6,7-tetrahydro-1,3-oxazepines. The method involves good to excellent yields and short reaction times.The reaction mechanism and the role of PPA esters were investigated in a chiral substrate.
- Mollo, María C.,Orelli, Liliana R.
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p. 6116 - 6119
(2016/12/09)
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- Heterocyclization Approach for Electrooxidative Coupling of Functional Primary Alkylamines with Aromatics
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A new approach for electrooxidative coupling of aromatic compounds and primary alkylamines bearing a functional group such as a hydroxyl group and an amino group was developed. The key to the success of the transformation is heterocyclization of functional primary alkylamines. Treatment of primary alkylamines bearing a functional group with nitriles or their equivalents gives the corresponding heterocycles. The electrochemical oxidation of aromatic substrates in the presence of the heterocycles followed by chemical reaction under nonoxidative conditions gave the desired coupling products.
- Morofuji, Tatsuya,Shimizu, Akihiro,Yoshida, Jun-Ichi
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supporting information
p. 9816 - 9819
(2015/08/24)
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- Magnesium bis(monoperoxyphthalate) hexahydrate as mild and efficient oxidant for the synthesis of selenones
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A new, efficient and mild method for the direct oxidation of selenides to selenones using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) has been developed. Noteworthy this transformation proceeds at room temperature, employs a cheap and safety oxi
- Temperini, Andrea,Curini, Massimo,Rosati, Ornelio,Minuti, Lucio
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supporting information
p. 1267 - 1271
(2014/06/24)
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- S-Co(II) cascade catalysis: Cyclocondensation of aromatic nitriles with alkamine
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A solvent-free S/Co(NO3)2 cascade catalyzed cyclocondensation reaction of aromatic nitriles with 3-amino-1-propanol or 2-aminoethanol has been successfully developed under thermal and microwave conditions. By this two-component protocol, mono- and bis-oxazines and oxazolines were selectively synthesized both in good to excellent yields and short reaction times. This catalytic system exhibits excellent chemoselectivity, and can be reused at least seven times without significant loss of activity in subsequent reactions.
- Ge, Haixia,Liu, Ping,Li, Xiangnan,Sun, Wei,Li, Jianli,Yang, Bingqin,Shi, Zhen
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p. 6591 - 6597
(2013/07/26)
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- Synthesis of 2-oxazolines and related N-containing heterocycles using [Et2NSF2]BF4 as a cyclodehydration agent
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The preparation of 2-oxazolines and related N-containing heterocycles from the corresponding hydroxyamides using XtalFluor-E ([Et2NSF 2s]BF4) as a cyclodehydration agent is described. A wide range of heterocycles are obtai
- Pouliot, Marie-France,Angers, Laetitia,Hamel, Jean-Denys,Paquin, Jean-Fran?ois
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p. 4121 - 4123
(2012/08/28)
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- A general and efficient palladium-catalyzed carbonylative synthesis of 2-aryloxazolines and 2-aryloxazines from aryl bromides
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Oxazoline is OK! A general and efficient method for the synthesis of oxazolines has been developed (see scheme). This allowed the preparation of 27 five-membered-ring heterocycles and 11 six-membered-ring heterocycles in moderate to good yields. Copyright
- Wu, Xiao-Feng,Neumann, Helfried,Neumann, Stephan,Beller, Matthias
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p. 13619 - 13623
(2013/01/15)
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- A green and selective synthesis of 2-aryloxazines and 2- aryltetrahydropyrimidines
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An efficient method for the selective synthesis of 2-substituted oxazines and tetrahydropyrimidines by the reaction of arylnitriles with 3-amino-1-propanol and 1,3-diaminopropane in the presence of montmorillonite K-10 and KSF as inexpensive, environmenta
- Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Eskandari, Zohre
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experimental part
p. 479 - 483
(2011/05/14)
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- H3PW12O40: An efficient and recyclable heterogeneous catalyst for the selective synthesis of 2-Aryl-5,6-dihydro-4H-1,3- oxazines and 2-Aryl-1,4,5,6-tetrahydropyrimidines
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An environmentally friendly and highly efficient procedure has been developed for the selective synthesis of 2-aryl-5,6-dihydro-4H-1,3-oxazines and 2-aryl-1,4,5,6-tetrahydropyrimidines by cyclocondensation of arylnitriles with 3-amino-1-propanol and 1,3-diaminopropane in the presence of catalytic amounts of H3PW12O40 under thermal conditions and MW irradiation. Under the same reaction conditions, dicyanobenzenes are transformed to their corresponding mono-oxazines and monotetrahydropyrimidines with excellent chemoselectivity. These reactions are simple and clean, giving the products in high yields and high purity. The catalyst can be easily recovered after the reaction and reused efficiently in subsequent runs.
- Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Eskandari, Zohre
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experimental part
p. 461 - 469
(2010/10/01)
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- Ultrasound promoted selective synthesis of 2-aryl-5,6-dihydro-4H-1,3-oxazines catalyzed by K-10 and KSF montmorillonite clays: A practical procedure under mild and solvent-free conditions
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Montmorillonite K-10 and KSF were found to be highly efficient, environmentally friendly and recyclable heterogeneous catalysts for the selective synthesis of a variety of 2-aryl-5,6-dihydro-4H-1,3-oxazines from arylnitriles and 3-amino-1-propanol under ultrasound irradiation. This new methodology provides excellent yields in short reaction times (10-25 min). The reaction work-up is very simple and the catalysts can be easily separated from the reaction mixture and reused several times in subsequent reactions. This catalytic system also exhibits excellent chemoselectivity in the synthesis of mono-oxazines from dinitriles.
- Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Eskandari, Zohre
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experimental part
p. 857 - 862
(2011/10/09)
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- The use of phosphonium anhydrides for the synthesis of 2-oxazolines, 2-thiazolines and 2-dihydrooxazine under mild conditions
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β-Hydroxy amides 6 and 7 were treated with triphenylphosphonium anhydride trifluoromethane sulfonate (3), or the cyclic analogue 4, to generate 2-oxazolines 5 and 8 under mild conditions. The reaction was optimised by examining the number of equivalents of reagents 3 or 4, or diisopropylethyl amine required to best effect cyclisation. The effects of altering the reaction temperature, reaction time, concentration, solvent, and addition rate also were investigated. However, it was found that use of a trityl group to block reaction at the hydroxyl or thiol group of the starting amides, and subsequent in situ detritylation, in the absence of base, led to greatly improved yields. Reagent 4 offered significant advantages in the purification of products and was used to dehydrate a range of trityl derivatives to form simple oxazolines, thiazolines, and a dihydro-1,3-oxazine, in high yield (85-99%), as well as a tetrahydro-1,3-oxazepine (31%).
- Petersson, Maria J.,Jenkins, Ian D.,Loughlin, Wendy A.
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supporting information; experimental part
p. 739 - 746
(2009/06/20)
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- An efficient, eco-friendly, one-pot protocol for the synthesis of 2-oxazolines promoted by ionic liquid/indium chloride
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2-Oxazolines have been synthesized using a solventless ionic liquid melt in good yields at ambient temperatures. The efficiency of various Lewis acid catalysts for the same reaction has been compared. The effectiveness of different alkyl chains in the ionic liquids for the synthesis of oxazolines has been studied and a butylmethylimidazolinium chloride/indium chloride melt has been found to be the best media for promoting the reaction. CSIRO 2006.
- Kamakshi,Reddy, Boreddy S.R.
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p. 463 - 467
(2007/10/03)
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- Efficient oxidative synthesis of 2-oxazolines
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New methodology for the synthesis of variously substituted 2-oxazolines and one dihydrooxazine using aldehydes, amino alcohols, and N-bromosuccinimide as an oxidizing agent is described. This one-pot synthesis is characterized by mild reaction conditions, broad scope, high yields, and its preparative simplicity. Georg Thieme Verlag Stuttgart.
- Schwekendiek, Kirsten,Glorius, Frank
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p. 2996 - 3002
(2008/02/10)
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- A simple synthesis of 2-substituted oxazolines and oxazines
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β-Aminoalcohols react with carboxylic acids in the presence of a zeolite, Ersorb-4, resulting in the formation of oxazoline derivatives in good yields. Similarly, 3-aminopropanol and benzoic acid gave the corresponding 2-phenyloxazine.
- Cwik, Agnieszka,Hell, Zoltán,Hegedüs, Adrienn,Finta, Zoltán,Horváth, Zoltán
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p. 3985 - 3987
(2007/10/03)
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- Synthesis of oxazines and thiazines by cyclodehydration of hydroxy amides and thioamides
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Dihydro-1,3-oxazines and -thiazines were obtained by cyclodehydration of hydroxy amides and thioamides with PEG-linked Burgess reagent or under Mitsunobu conditions. Yields were generally higher with polymer-Burgess reagent, but both conditions failed to
- Wipf, Peter,Hayes, Gregory B.
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p. 6987 - 6998
(2007/10/03)
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- One-step conversion of aldehydes to oxazolines and 5,6-dihydro-4H-1,3-oxazines using 1,2- and 1,3-azido alcohols
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The reactions of 1,2- and 1,3-hydroxy azides with aldehydes under acidic conditions were examined. A variety of Lewis acids were examined, of which BF3·OEt2 was found the most convenient. Trimethylsilyl ether derivatives of the alcohols could also be reacted using trimethylsilyl triflate as the promoter. Twenty-five examples that proceed in moderate to quantitative yields are reported.
- Badiang, Jennifer G.,Aube, Jeffrey
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p. 2484 - 2487
(2007/10/03)
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- Reactions of N-Benzyl- and N-Benzylidene-alkanolamines with Bromine: Formation of 1,3-Oxazolidines, 1,3-Oxazinanes, 4,5-Dihydro-1,3-oxazoles and 5,6-Dihydro-4H-1,3-oxazines
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N-Methylbenzylamines react with bromine in acetonitrile to form N-benzylidenemethylamines.Under similar conditions 2-benzylaminoethanols and 3-benzylaminopropan-1-ols afford 3-benzyl-2-phenyl-1,3-oxazolidines and 3-benzyl-2-phenyl-1,3-oxazinanes, respectively. 2-Benzylidineaminoethanols and 3-benzylideneaminopropan-1-ols likewise give 2-aryl-4,5-dihydro-1,3-oxazoles and 2-aryl-5,6-dihydro-4H-1,3-oxazines, respectively.When N-benzylidenemethylamine is treated with bromine in the presence of alcohols, benzaldehyde acetals are obtained.
- Goosen, Andre,McCleland, Cedric W.,Sipamla, Allworth M.
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p. 2221 - 2232
(2007/10/03)
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- Synthesis of Δ2-1,3-oxazolines and Δ2-1,3-oxazines using potassium fluoride on alumina
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Potassium fluoride (40%) on alumina was used as a basic reagent for the ring closure of N-(β- or γ-haloalkyl)amides to give Δ2-1,3-oxazolines and Δ2-1,3-oxazines, respectively. Various 2-alkyl and 2-aryl derivatives were synthesized in moderate to high yield under relatively mild conditions (KF/Al2O3, solvent, room temperature). The procedure also facilitated simple workup and purification of the products. New compounds synthesized by this method are: 5-bromomethyl-2-phenyl-Δ2-1,3-oxazoline, 4,4-dimethyl-2-vinyl-Δ2-1,3-oxazoline, and 5-methylene-2-phenyl-Δ2-1,3-oxazine. The last compound represents the first authentic example of a 5-functionally substituted oxazine without substitution in the 4- or the 6-position.
- Mitchell,Benicewicz
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p. 675 - 677
(2007/10/02)
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- Selective synthesis of heterocyclic compounds through the intramolecular substitution of phenylselenonyl group by nitrogen or carbonyl oxygen in amides
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Nitrogen heterocycles were produced by the oxidation of N-[ω-(phenylseleno)alkyl]-p-toluenesulfonamides through the intramolecular substitution of the resultant phenylselenonyl group by the nitrogen atom. By the oxidation of the corresponding benzamides,
- Toshimitsu,Hirosawa,Tanimoto,Uemura
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p. 4017 - 4020
(2007/10/02)
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- Studies on β-Lactams: Synthesis of Some Penams, Cephams and Their 1-Oxa Analogs
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5,6-Dihydro-4-hydroxy-4-methyl-2-phenyl-1,3-thiazine (1a), after the protection of its hydroxy group with trimethylsilyl chloride, reacts with phenoxyacetyl chloride in the presence of triethylamine to give the hydroxycepham (IIa). 1,3-Oxazines (Ib and Ic
- Sharma, S. D.,Mehra, Usha,Kaur, Sukhjinder
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p. 857 - 859
(2007/10/02)
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- Reactions of 1,2- and 1,3-amino-alcohols with imidate salts and with ortho esters
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ω-Hydroxy-N-substituted amidines have been shown to be the intermediates in the formation of 2-oxazolines and 5,6-dihydro-4H-1,3-oxazines from the reactions of imidates and 1,2- and 1,3-amino-alcohols respectively, 1,2- and 1,3-Amino-alcohols also react with ortho esters to give 2-oxazolines and 5,6-dihydro-4H-1,3-oxazines, but N-acylamino-alcohols give rise to oxazolidines with ortho esters.
- Butt, Mohammed I.,Neilson, Douglas G.,Watson, Kathleen M.,Zakir-Ullah
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p. 2328 - 2332
(2007/10/04)
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