Summary: | 碩士 === 台北醫學院 === 藥學研究所 === 85 === GITC(2,3,4,6-tetra-O-acetyl-b-D-glucopyranosyl isothiocyanate)
is one GITCof the most widely applicable chiral
derivatizing agent to resolve racemic amines . GITC
containing isothiocyanate active moiety can react with those
compounds contain amine functional group. Good resolution of the
diastereomeric thiourea derivatives is generally achieved by
HPLC via UV detection .Due to weak chromophore , GITC
is not sensitive enough to be detected in low
concentration . In order to improve the detection sensitivity,
fluorescent chiral derivatizing agent,CGIT [6-O-(4'-
methylcoumarin-7'- methoxycarbonyl)-2,3,4-tri-O-
acetyl-a-D-glucopyranosyl isothiocyanate] was
developed previously in our laboratory . Now we like to report
here the synthesis of another new fluorescent chiral
derivatizing agent,AFGIT [6-
(9'-aminofluorenyl)-2,3,4-tri-O-acetyl-b-D-glucunopyranosyl
isothiocyanate] . Glucuronolactone is served as a starting
material for the preparation of AFGIT . Glucuronolactone
was reacted with NaOH in 50% CH3OH aqueous to
produce sodium glucuronate,and then was acetylated
in the presence of p-toluenesulfonic acid . Incoporation of
9-aminofluorene to tetra-O-acetyl glucuronic acid as an
amide linkage and following reaction with HBr affored
the acetobromoglucuronic acid,subsequent reaction with
AgSCN yielded the fluorescent chiral derivatizing agent,AFGIT .
Derivatization was performed by reaction of AFGIT with primary
or secondary amines in CH3CN for one hour .
However amino acids were reacted in 50% aqueous
CH3CN catalyzed by triethylamine for one hour .
These diastereoisomeric thioureas was separated on a reversed
HPLC column (C18) with a fluorescence detector
(λex. : 270 nm ,λem. : 310 nm). Mobile phase of 55~70%
CH3OH in 0.1% H3PO4 solution for racemic amino
acids,60% CH3CN in 0.1% H3PO4 aqueous (v/v) for racemic
adrenergic b-blockers,and CH3CN : CH3OH : 0.1%
H3PO4 aqueous = 40 : 20 : 40 (v/v/v) for
phenethylamines were applied . Twelve racemic amino acids (a
=1.04~1.71) , four adrenergic b-blockers (a>1.1),and four
phenethylamines (a=1.05~1.15) were resolved successfully.
Comparison of the detection sensitivity of DL-alanine
derivatives of AFGIT and GITC, the detection sensitivity
of AFGIT derivatives were at least 18 times more
stronger then those of GITC derivatives . In conclusion,the new
chiral derivatizing agent,AFGIT,is not only useful
to resolve the racemic amine drugs or amino acids
but also to enhance their detection sensitivity by the
developed methods.
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