- Synthesis of 2-oxazolines via boron esters of N-(2-hydroxyethyl) amides
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A new, convenient, one-pot process is presented for the synthesis of 2-oxazolines in high yields (75-94%) via boron esters of N-(2-hydroxyethyl) amides. The procedure involves thermolysis of the boron esters at 240-260 °C, in the presence of solid CaO as an acid scavenger and allows the preparation of oxazolines from hydroxyethyl amides of aliphatic and aromatic monocarboxylic acids.
- Ilkgul, Baris,Gunes, Deniz,Sirkecioglu, Okan,Bicak, Niyazi
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- Sulfonimidation via ring-opening of 2-oxazolines with acidic sulfonimide nucleophiles
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Acidic sulfonimide nucleophiles including dibenzenesulfonimide, o-benzenesulfonimide, dimethanesulfonimide, and N-(methylsulfonyl)-benzenesulfonamide are discovered to open a variety of alkyl-, aryl- and heteroaryl-2-oxazoline rings to provide the sulfonimidation products in refluxing 1,4-dioxane. The electron-rich 2-oxazoline substrates worked well for the nucleophilic ring-opening reactions while no reaction took place for the electron-poor 2-oxazoline substrates.
- Gutierrez, David A.,Dean, Dayton R.,Laxamana, Candace M.,Migliozzi-Smith, Madyson,O'Brien, Connor J.,O'Neill, Claire L.,Li, Jie Jack
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p. 261 - 276
(2016/07/06)
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- CuCl-catalyzed radical cyclisation of N-α-perchloroacyl-ketene-N,S- acetals: A new way to prepare disubstituted maleic anhydrides
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The copper-catalyzed radical cyclization (RC) of N-α-perchloroacyl cyclic ketene-N,X(X=O, NR, S)-acetals was studied. While the RC of N-acyl ketene-N,O-acetals was unsuccessful, the 5-endo cyclization of the other ketene acetals provided much better results, with the following order of cyclization efficiency: hexa-atomic cyclic ketene-N,NR-acetalspenta-atomic cyclic ketene-N,S-acetalshexa-atomic cyclic ketene-N,S-acetals. Invariably the catalytic cycle begins with the formation of a carbamoyl methyl radical. This leads to a cascade of reactions, including a radical polar crossover step, which ends with the formation of the maleimide nucleus, or precursors of this. Products from the RC of the hexa-atomic cyclic ketene-N,S-acetals, were efficiently transformed into disubstituted maleic anhydrides.
- Cornia, Andrea,Felluga, Fulvia,Frenna, Vincenzo,Ghelfi, Franco,Parsons, Andrew F.,Pattarozzi, Mariella,Roncaglia, Fabrizio,Spinelli, Domenico
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experimental part
p. 5863 - 5881
(2012/09/22)
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- Generation of cyclic ketene-N,X-acetals (X = O, S) from 2-alkyl-1,3-oxazolines and 2-alkyl-1,3-thiazolines. Reactions with acid chlorides, 1,3-diacid chlorides and N-(chlorocarbonyl) isocyanate
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2-Alkyl-1,3-oxazolines, 2-alkyl-1,3-thiazolines, and the corresponding cyclic ketene-N,X-acetals (X = O, S) derived from them were reacted with monoacid chlorides, diacid chlorides, triacid chlorides. A series of these carbon-carbon bond-forming reactions and cyclizations to both substituted 2,3-dihydrooxazolo[3,2-a]pyridine-5,7-diones and 2,3-dihydrothiazolo[3,2-a] pyridine-5,7-diones proceeded under mild reaction conditions. Cyclic ketene-N,X-acetal intermediates play important roles in all these reactions. Related cyclizations with N-(chlorocarbonyl) isocyanate formed substituted 2,3-dihydrooxazolo[3,2-c]pyrimidine-5,7-diones and 2,3-dihydrothiazolo[3,2-c] pyrimidine-5,7-diones. Georg Thieme Verlag Stuttgart.
- Zhou, Aihua,Pittman Jr., Charles U.
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- Platinum catalysed hydrolytic amidation of unactivated nitriles
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The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N- substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported. Isolated yields vary from 51-89%. (C) 2000 Elsevier Science Ltd.
- Cobley, Christopher J.,Van Den Heuvel, Marco,Abbadi, Abdelilah,De Vries, Johannes G.
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p. 2467 - 2470
(2007/10/03)
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- Hyper comb-branched polymer conjugates
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A novel class of hyper comb-branched polymers conjugated with carried materials are disclosed.
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- Manufacture of 2-oxazolines, 2-oxazines, 2-imidazolines and 2-imidazines
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A process for the production of a product selected from the group consisting of a 2-oxazoline or a 2-oxazine and a 2-imidazoline or a 2-imidazine comprising reacting a bicyclic amide acetal with a member selected from the group consisting of an alkanol amine and an alkylene polyamine, respectively, at a temperature in the range of from about 20° C. to 200° C. is described.
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- REACTION OF YNAMINES WITH BIFUNCTIONAL REAGENTS
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The reaction of 1-diethylamino- and 1-(ethylphenylamino)-1-propynes with aromatic and aliphatic bifunctional reagents was invectigated.In the reactions of the ynamines with aromatic binucleophiles and also with ethenolamine and ethylenediamine heterocyclic compounds of the benzodioxole, benzimidazoline, benzoxazole, benzothiazole, oxazoline, and imidazoline series are formed.The reactions of the ynamines with ethylene glycol and dithioglycol gave amino(alkoxy)alkenes and amino(alkylthio)-alkenes.
- Sokolova, E. A.,Maretina, I. A.,Petrov, A. A.
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p. 1500 - 1505
(2007/10/02)
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- Process for preparing 2-oxazolines
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A cyclodehydration reaction is described for preparing 2-oxazolines which comprises reacting in liquid phase (a) an N-(2-hydroxyalkyl)carboxamide with (b) a small but catalytic amount of an iron-containing compound. The reaction is normally conducted at elevated temperatures (e.g., 180°-200° C.) and under reduced pressure. Both 2-H- and 2-substituted-2-oxazolines are prepared by this process. For example, 2-H-2-oxazoline and 2-ethyl-2-oxazoline were prepared in 83.1 percent and 90.2 percent yields, respectively, by contacting the appropriate N-(2-hydroxyethyl)carboxamide with ferrous chloride tetrahydrate at temperatures of approximately 180°-200° C./50 mm Hg. Under these conditions, the oxazoline product and water were codistilled from the reaction mixture essentially as fast as they were formed.
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