- N-tosyl-(S)-prolyl chloride in kinetic resolution of racemic heterocyclic amines
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The kinetic resolution of racemic heterocyclic amines via acylation with N-tosyl-(S)-prolyl chloride was systematically investigated. It was established that racemic mixtures of aromatic amines could be resolved with high efficiency, while the acylation of 2- and 3-methylpiperidines occurred with low diastereoselectivity. A method for the preparation of enantiomerically pure (3R)-7,8-difluoro-3-methyl-3,4-dihydro-2H-[1,4]benzoxazine was developed.
- Gruzdev,Vakarov,Levit,Krasnov
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- A comparative study on the acylative kinetic resolution of racemic fluorinated and non-fluorinated 2-methyl-1,2,3,4-tetrahydroquinolines and 3,4-dihydro-3-methyl-2H-[1,4]benzoxazines
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The acylative kinetic resolution of racemic 6-fluoro-2-methyl-1,2,3,4- tetrahydroquinoline, 7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine, and their non-fluorinated analogues with (S)-naproxen and N-phthaloyl-(S)-amino acyl chlorides has been carried out. It has been shown that the presence of fluorine atoms in the aromatic fragment of a heterocyclic amine results in the increasing stereoselectivity of acylation with (S)-naproxen acyl chloride and in a decrease in the efficiency of acylative kinetic resolution using N-phthaloyl-(S)-amino acyl chlorides. A method for the preparation of enantiopure (S)-6-fluoro-2-methyl-1,2,3,4-tetrahydroquinoline (ee >99%) was developed.
- Gruzdev, Dmitry A.,Chulakov, Evgeny N.,Levit, Galina L.,Ezhikova, Marina A.,Kodess, Mikhail I.,Krasnov, Victor P.
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- Acylative kinetic resolution of racemic heterocyclic amines with (R)-2-phenoxypropionyl chloride
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The acylative kinetic resolution of racemic heterocyclic amines such as 3,4-dihydro-3-methyl-2H-[1,4]benzoxazines, 3,4-dihydro-3-methyl-2H-[1,4]benzothiazine, 2-methyl-1,2,3,4-tetrahydro-quinolines and 2-methylindoline with enantiopure (R)-2-phenoxypropionyl chloride has been studied. It has been found that acylation of 3,4-dihydro-3-methyl-2H-[1,4]benzothiazine proceeds with the best stereoselectively when compared with other racemic amines. An efficient method for the preparation of (S)-3,4-dihydro-3-methyl-2H-[1,4]benzothiazine (99.4% ee) via a kinetic resolution protocol was developed. The possibility of recycling (R)-2-phenoxypropionic acid has been demonstrated.
- Vakarov, Sergey A.,Gruzdev, Dmitry A.,Chulakov, Evgeny N.,Sadretdinova, Liliya Sh.,Tumashov, Andrey A.,Pervova, Marina G.,Ezhikova, Marina A.,Kodess, Mikhail I.,Levit, Galina L.,Krasnov, Victor P.,Charushin, Valery N.
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supporting information
p. 1231 - 1237
(2016/11/23)
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- Diastereoselective acylation of racemic heterocyclic amines with N-tosyl-(s)-prolyl chloride and its structural analogs
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A comparative study on the kinetic resolution of racemic amines (2,3-dihydro-4H-1,4-benzoxazine and 1,2,3,4-tetrahydroquinoline derivatives) via diastereoselective acylation with N-tosyl-(S)-prolyl chloride and its structural analogs was performed. The effect of resolving agent structure on the stereoselectivity of heterocyclic amine acylation was examined. The highest stereoselectivity was achieved in the case of acylation with acyl chlorides bearing a conformationally restricted pyrrolidine ring and an aromatic substituent in the protecting group at the nitrogen atom.
- Vakarov,Gruzdev,Chulakov,Sadretdinova,Ezhikova,Kodess,Levit,Krasnov
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p. 838 - 855
(2015/09/28)
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- Diastereoselective acylation of racemic heterocyclic amines with N-tosyl-(S)-prolyl chloride and its structural analogs
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A comparative study on the kinetic resolution of racemic amines (2,3-dihydro-4H-1,4-benzoxazine and 1,2,3,4-tetrahydroquinoline derivatives) via diastereoselective acylation with N-tosyl-(S)-prolyl chloride and its structural analogs was performed. The effect of resolving agent structure on the stereoselectivity of heterocyclic amine acylation was examined. The highest stereoselectivity was achieved in the case of acylation with acyl chlorides bearing a conformationally restricted pyrrolidine ring and an aromatic substituent in the protecting group at the nitrogen atom.
- Vakarov,Gruzdev,Chulakov,Sadretdinova, L. Sh.,Ezhikova,Kodess,Levit,Krasnov
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p. 838 - 855
(2014/11/08)
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- A facile synthesis of (S)-(-)-7,8-difluoro-3,4-dihydro-3-methyl-2H-1,4-benzoxazine by zinc chloride assisted Mitsunobu cyclization reaction
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A convenient procedure for preparation of the title compound of ≤ 99% ee starting from 1-(2,3-difluoro-6-nitrophenoxy)-2-propanone (3) is presented. The key reaction is the intramolecular cyclization reaction in the presence of zinc chloride.
- Kang, Soon Bang,Ahn, Eu Jin,Kim, Youseung,Kim, Yong Hae
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p. 9317 - 9320
(2007/10/03)
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