非常详细的综述性文章
药学学报Acta
PharmaceuticaSinica
2007,42(2):111—117
available
impact
to
minimize
oreven
abolishthe
negative
alsosuccessfully
applied
to
theassemblyofpeptides
ofthe
these
use
sequencesduringsynthesis.These
reagents。…,
in
containingseveralsecondaryandhinderedamines.2
ReasonableroutesforfragmentscouplingSegmentscondensationis
synthesis
of
long
sequence
an
includewhich
ofgive
powerful
a
acylating
protocolssignificant
increasethefor
importantwayforthepeptide.
“Difficult
efficiencyofpeptide
chain
assembly,especially
‘‘difficultsequences”.Thepopularityofuroniumbasedcouplingreagents
for
peptide
synthesis
has
increasedthatproved
as
sequences”may
becircumventedbyadequatedefinition
correct
ofsegmentand
For
choiceofcondensationsite[9|.
can
significantly(Figure1).Certain
to
sequences
longpeptidessynthesis,thetargetpeptide
into
several
protected
were
or
be
bemore
difficult
to
synthesize,such
BoPrPdividedcarboxyl
fragments.Those
chosen
which
amino
(bovine
Prion
Protein)(90—200),were
a
successfullycomponents
Gly
to
generally
as
preparedusing
combinationofthe
highlyactivated
usuallycontainacid.in
order
Pro
the
C—terminal
couplingreagent
1,
HATU(O一(7-azabenzotrizole一1一y1)一
hexanuorophosphate)
total
of
and
et
minimizethe
possibleracemization
1,3,3一tetramethyluronium
duringtheshortfragmentssynthesis,andthen,口一sheet
was
not
(Figure
1)
t-Boc
(tert.butyloxycarbonyl)
synthesis
the
tendency
to
beformedinthe
produced
chemistry[3].Wu
al[7]reported
longer
intermediate㈨.In
should
otherword,whenthelonger
performed,the
at
human理一defensins4,5,and6,usingthe
optimizedneutraliza—
fragmentscondensationreactionswerePro
residue
be,if
of
DIEA(N,N—diisopropylethylamine)in
tetramethyluronium
activationreport
situ
possibly,locatedC—terminal
in
a
the
tion/HBTU(2一(1H—benzotriazol一1一y1)一1,1,3,3一
hexanuorophosphate)(Figure1)
highlyefficientsyntheticapproach
to
central
segment.
position
insteadrelated
protocolforsolid—phaseBocchemistry.Their
a
Astrategysuitableforthedesignofsynthetic
for
human
proinsulin
route
described
C—peptide(Figure
2)was
thesethreeimportantimmunologicmolecules.Excellentresuhshave
been
also
obtained
for
the
reasonableinviewofthesolubilitypredictionmethod.Assembledpeptideintermediates
in
Fmoc(9一
syntheses
ofhashaveArg,
the
route
Awere
nuorenylmethyloxycarbonyl)
peptidesusing
the
activating
solid—phase
reagent
sufficientlysoluble
to
in
thepolarsolventsandsusceptible
HBTU.It
the
subsequent
to
fragment
route
condensations①一⑥.
erroneousroute
beenobservedthat
complete
couplingreactions
as
Contrary
was
theproperA,ifthe
B
finishedinonly10—30min.Residuessuch
chosen,theacidcomponentcandidateobtainedby
confrontwiththeinsolubilitythetargetcompound.
Ile,LeuandVal,whichoftenrequiredoublecouplingby
altered
activation
thecondensation5wouldproblem
on
methods,
react
with
high
theway
to
get
efficiencybysinglecouplingwhenHBTUisused.The
Fmoc/HBTUchemistrythe
peptide
auto
hasrecentlybeenappliedinto
of
RouteA
EAEDLQVGQVELG
Rou【e
synthesizers.Theincorporation
tritylside--chainprotectionforFmoe— AsnandFmoc--Ginfurther
enhances
coupling
efficiencies
in“difficuh
B
L一4—J
GGPGAGSL
L——一o——_J.QP
LALE
o.一G1—S—LoQ
I--—-----------一3 ---- —----—--_J
sequences”.Earlierstudiesshowedthatseveralothercouplingmethods,includingthosephosphoniumbased
agents
:……一一X…………一一j
Figure2peptide
Two
routes
in
thesynthesisofproinsulinC—
such
as
BOP((benzotriazol一1一yl—N—oxy)tris
(dimethylamino)phosphoniumhexanuorophosphate),
PyBOPrbenzotriazol— 1 yl -oxy—-tris—-pyrrolidino— phospho— nium
3
Reversibleamide.backbonesubstitutionAnotherpowerfulstrategyused
to
hexanuorophosphate)Lj(Figure1),have
8
been
combat“difficult
、
\
Me2N.,,+
Me2N_P—O\
Me2N
PF;
p恻
Q呼
p一
HAIV
Figure1
BOP
PyBOP
Chemicalstructuresofselectedcouplingreagents