TY - BOOK
T1 - Reactivity of aminodeoxyalditols and derivatives in hydrogen
fluoride.
T2 - Ph.D. thesis.
AU - Norrild, Jens Chr.
PY - 1996
Y1 - 1996
N2 - Reactions of a series of aminodeoxy-pentitols and -hexitols in
anhydrous hydrogen fluoride with formic acid as catalyst gave the
corresponding 2,5 and 3,6-anhydro-aminodeoxyhexitols respectively
in yields of more than 95%. In the analogous reaction of
3-amino-3-deoxy-D-altritol a dianhydride, namely
3-amino-3-deoxy-1,4:2,6-dianhydro-D-altritol, was obtained. The
reactions proceed via an intramolecular endo opening of
formoxonium intermediates by suitably placed hydroxy groups. A
series of further deoxygenated aminodeoxyhexitols was prepared.
These compounds, in which the preferred ring-closure was
obstructed, were treated with hydrogen fluoride in the presence of
a carboxylic acid catalyst. The products from these reactions,
including 2,6-anhydrides, were assigned. In case of
1-amino-1,6-dideoxy- or 1-benzylamino-1,3,6-trideoxy-hexitols very
efficient and regioselective conversions to the corresponding
2,5-anhydrides were achieved. These compounds can be recognized as
muscarine analogues or precursors. The general mechanism of the
reactions was evaluated by 13C NMR spectroscopic studies of the
acyloxonium ion intermediates.A series of
1-deoxy-1-trifluoroacetamido-hexitols was prepared and treated
with anhydrous hydrogen fluoride. Very stereo- and regioselective
reactions to the C-2 inverted 2,5-anhydrides were observed in
yields of more than 80%. The reactions proceed via 1,2-fused
2-trifluoromethyl-oxazolinium ions which react by an
intramolecular attack by HO-5 at C-2 forming a five membered ring
with inversion of the configuration at C-2. The intermediate
oxazolinium ions of representative reactions were characterized by
their 13C NMR spectra.
AB - Reactions of a series of aminodeoxy-pentitols and -hexitols in
anhydrous hydrogen fluoride with formic acid as catalyst gave the
corresponding 2,5 and 3,6-anhydro-aminodeoxyhexitols respectively
in yields of more than 95%. In the analogous reaction of
3-amino-3-deoxy-D-altritol a dianhydride, namely
3-amino-3-deoxy-1,4:2,6-dianhydro-D-altritol, was obtained. The
reactions proceed via an intramolecular endo opening of
formoxonium intermediates by suitably placed hydroxy groups. A
series of further deoxygenated aminodeoxyhexitols was prepared.
These compounds, in which the preferred ring-closure was
obstructed, were treated with hydrogen fluoride in the presence of
a carboxylic acid catalyst. The products from these reactions,
including 2,6-anhydrides, were assigned. In case of
1-amino-1,6-dideoxy- or 1-benzylamino-1,3,6-trideoxy-hexitols very
efficient and regioselective conversions to the corresponding
2,5-anhydrides were achieved. These compounds can be recognized as
muscarine analogues or precursors. The general mechanism of the
reactions was evaluated by 13C NMR spectroscopic studies of the
acyloxonium ion intermediates.A series of
1-deoxy-1-trifluoroacetamido-hexitols was prepared and treated
with anhydrous hydrogen fluoride. Very stereo- and regioselective
reactions to the C-2 inverted 2,5-anhydrides were observed in
yields of more than 80%. The reactions proceed via 1,2-fused
2-trifluoromethyl-oxazolinium ions which react by an
intramolecular attack by HO-5 at C-2 forming a five membered ring
with inversion of the configuration at C-2. The intermediate
oxazolinium ions of representative reactions were characterized by
their 13C NMR spectra.
M3 - Book
BT - Reactivity of aminodeoxyalditols and derivatives in hydrogen
fluoride.
PB - Technical University of Denmark
CY - Lyngby
ER -