S 98 Synthesis of 4-amino derivatives of 5-oxoproline [Text] / V. P. Krasnov, A. Yu. Vigorov, I. A. Nizova, T. V. Matveeva, A. N. Grishakov, I. V. Bazhov, A. A. Tumashov, M. A. Ezhikova, M. I. Kodess // European Journal of Organic Chemistry. - 2007. - № 25. - P4257-4266 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The possibility of obtaining the stereoisomeric derivatives of 5-oxoproline and glutamic acid with a tertiary amino group at C-4, using the nucleophilic substitution of bromine in dimethyl (2S,4RS)-4-bromo-N-phthaloylglutamate with secondary amines followed by resolution of diastereomers and removal of protecting groups has been studied. We have shown that the reaction with arylamines results in optically pure 5-oxoproline derivatives in high yields. In the case of more basic amines, the reaction is accompanied by racemization, and the target products can be isolated only as diastereomeric racemates. |
K 46 Kinetic resolution of heterocyclic amines by reaction with optically active acid chlorides. The effect of reaction conditions on the diastereoselectivity of acylation of (±)-3-methyl-2,3-dihydro-4H-1,4-benzoxazine [Electronic resource] / V. P. Krasnov, G. L. Levit, M. A. Koroleva, I. M. Bukrina, L. Sh. Sadretdinova, I. N. Andreeva, V. N. Charushin, O. N. Chupakhin // Russian Chemical Bulletin (Translation of Izvestiya Akademii Nauk, Seriya Khimicheskaya). - 2004. - Vol. 53, № 6. - P1253-1256 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: The influence of the reaction conditions (solvent, base) on the diastereoselectivity of acylation of (±)-3-methyl-2,3-dihydro-4H-1,4-benzoxazine with (S)-naproxen and N-tosyl-(S)-proline chlorides was studied. The highest diastereoselectivity was observed for the reaction carried out in benzene in the presence of aliphatic tertiary amines \\\\Expert2\\nbo\\Russian Chemical Bulletin\\2004, 53 (6), 1253.pdf |
S 89 Structures of the racemate and (S)-enantiomer of 7,8-difluoro-3-methyl-2,3-dihydro-4H-[1,4]benzoxazine [Electronic resource] / P. A. Slepukhin, D. A. Gruzdev, E. N. Chulakov, G. L. Levit, V. P. Krasnov, V. N. Charushin // Russian Chemical Bulletin (Translation of Izvestiya Akademii Nauk, Seriya Khimicheskaya). - 2011. - Vol.60, №5. - С. 955-960. - Bibliogr. : p. 960 (17 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ENANTIOMERS -- RACEMATES -- ORGANOFLUORINE COMPOUNDS Аннотация: The comparative X ray diffraction study of racemic and (S) enantiomer of 7,8 difluoro 3 methyl 2,3 dihydro 4H [1,4]benzoxazine was carried out. The both forms of benzoxazine are crystallized in the orthorhombic crystal system, the (S) enantiomer is crystallized in the chiral space group P212121, while the racemate is crystallized in the centrosymmetric Pbca space group. The bond lengths and bond and torsional angles in the both molecules are almost equal. The packing of the racemate is characterized by a closer interaction of polar NH...О groups. \\\\expert2\\NBO\\Russian Chemical Bulletin\\2011, 60 (5), 955-960.pdf |
E 54 Enantiomers of all-cis-5-(4-bromophenyl)-4-tert-butoxycarbonyl-2-methoxycarbonylpyrrolidine: preparative HPLC separation and acylative kinetic resolution of the racemate / E. N. Chulakov, D. A. Gruzdev, G. L. Levit, K. V. Kudryavtsev, V. P. Krasnov // Tetrahedron: Asymmetry . - 2012. - Vol.23. - С. 1683-1688. - Bibliogr.: p. 1687-1688 (15 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ENANTIOMERS -- HPLC -- RACEMATES Аннотация: The fundamental possibility of acylative kinetic resolution of racemic heterocyclic amines was demonstrated by the example of all-cis-5-(4-bromophenyl)-4-tert-butoxycarbonyl-2-methoxycarbonylpyrrolidine. Individual enantiomers (ee >99%) were obtained in high yields via preparative chiral HPLC \\\\expert2\\NBO\\Tetrahedron Asymmetry\\2012, v. 23, p.1683.pdf |