NITRILE OXIDES IN MEDICINAL CHEMISTRY .4. CHEMOENZYMATIC SYNTHESIS OF CHIRAL HETEROCYCLIC-DERIVATIVES
Articolo
Data di Pubblicazione:
1992
Citazione:
NITRILE OXIDES IN MEDICINAL CHEMISTRY .4. CHEMOENZYMATIC SYNTHESIS OF
CHIRAL HETEROCYCLIC-DERIVATIVES / M. De Amici, P. Magrì, C. De Micheli, F. Cateni, R. Bovara, G. Carrea, S. Riva, G. Casalone. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 57:10(1992), pp. 2825-2829. [10.1021/jo00036a013]
Abstract:
The two enantiomers of 3-bromo-5-(hydroxymethyl)-DELTA-2-isoxazoline (1)
and 2-phenyl-5-(hydroxymethyl)-isoxazolidin-3-one (9) have been prepared
in enantiomeric excess higher than 90\% by hydrolysis of the
corresponding butyrates under the catalysis of lipase PS, which was the
most selective catalyst of the enzymes tested. The pairs of enantiomers
of 1 and 9 were transformed into the chiral forms of the potent
muscarinic ligands 3 and 5. The results obtained with the homogeneous
set of esters 6, 7, 10a-d evidence a strong dependence of reaction rate
and enantioselectivity of the lipase PS-catalyzed transformations upon
both the size of the acyl moiety and the shape of the group carrying the
alcoholic part of the ester. In the series of esters 10a-d, the best
results were obtained with butyrate 10b. Quite interestingly, on passing
from the butyrate of 1 to that of 9, the value of the enantiomeric ratio
remained remarkably high but the enantiopreference switched from R to S.
In between lies the butyrate of
2-methyl-5-(hydroxymethyl)isoxazolidin-3-one {[(+/-)-6] which was
barely recognized by lipase PS and yielded alcohol (R)-(-)-2 in a modest
enantiomeric excess.}
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
M. De Amici, P. Magrì, C. De Micheli, F. Cateni, R. Bovara, G. Carrea, S. Riva, G. Casalone
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