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Chiral 1,4-Benzodiazepines. VIII. Concerning the Rate of WD Exchange and Optical Stability of the Chiral Centre C(3).

M. Štromar ; CRC, Compagnia di Ricerca Chimica, S. A., Chiasso, Switzerland
V. Šunjić ; RC, Compagnia di Ricerca Chimica, S. A., Chiasso, Switzerland
T. Kovač ; RC, Compagnia di Ricerca Chimica, S. A., Chiasso, Switzerland
L. Klasinc ; RC, Compagnia di Ricerca Chimica, S. A., Chiasso, Switzerland
F. Kajfež ; RC, Compagnia di Ricerca Chimica, S. A., Chiasso, Switzerland


Puni tekst: engleski pdf 9.923 Kb

str. 265-274

preuzimanja: 161

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Sažetak

Various chiral substituted 1,4-benzodiazepin-2-ones with 3-
-acyloxy (general formula I), 3-hydroxy- and 3-alkoxy (general
formula II), 3-alkyl (general formula III) and 3-quaternary ammonium
(general formula IV) groups as substituents were subjected
to C(3)-H-D exchange rate measurements in order to obtain information
on the optical stability of the chiral centre and on the
mechandsm of racemization. Only type IV compounds (IVa-j)
exhibited H/D exchange, but acid catalyzed racemization took
place in type I and II compounds, indkating some other mechani.
sms in this process. Type III compounds as free bases (IIIa-c),
N4-protonated acids, or N4-oxides (III, e; f) underwent no H/D
exchange and are optically sfable as well. In cases whe,re deprotonation-
reprotonation mechanism of racemization can be excluded
two other mechanisms are discussed, i. e. acid-'catalyzed ring-chain
tautomerism and identity substitution with alkoxide ion.

Ključne riječi

Hrčak ID:

196810

URI

https://hrcak.srce.hr/196810

Posjeta: 318 *