S. Matile et al.
FULL PAPERS
Routine spectroscopic and
analytical characterization of all
new compounds was in agree-
ment with sample structure,
purity, and homogeneity. Chiral
compounds
were
optically
active, no indication of epimeri-
zation was visible in their
1H NMR spectra, results from
reverse-phase (RP)-HPLC of
the protected target molecules
gave single peaks.[56]
Characterization: The ability
of the reactive carboxylates
C1H1–C1H3 and phosphonates
P1H1–P1H3 to capture hydro-
phobic analytes on the one
hand and activate CPP trans-
porters on the other hand was
determined under routine con-
ditions[35–48] with octanal O2 as
the representative analyte[44,45]
and poly-l-arginine (pR, MW
13,300, DP 72) as the represen-
tative CPP transporter.[36,39,42,46]
Anionic amphiphiles C1H1O2-
C1H3O2
and
P1H1O2-
P1H3O2 were prepared indi-
vidually by incubation with 2
equivalents of O2 per hydrazide
in DMSO for 1 hour at 608C
(Scheme 2).[44,45]
Quantitative
hydrazone formation was con-
firmed by mass spectrometry.
The activation of pR as an
anion transporter was explored
in standard EYPC-LUVsꢀCF
(i.e., egg-yolk phosphatidylcho-
line (EYPC) large unilamellar
vesicles (LUVs) loaded with
the
anionic
fluorophore
5(6)-carboxyfluorescein (CF) at
concentrations high enough for
self-quenching
to
occur).[36,39,42,46] In this assay,
the ability of CF to leave the
vesicle is reported as fluores-
cence recovery caused by mini-
mized self-quenching in re-
sponse to local dilution. This re-
sponse is independent of the
mechanism of transport, al-
though extensive early studies
in bulk (U-tube) and lipid-bi-
layer membranes have con-
Scheme 3. a) 1. 2, DIEA, DMAP, DCM, 08C, 70%; 2. NaOH (1m), EtOH, 79%; 3. HCl (3m), 84%.
b) 1. HBTU, DIEA, DCM, RT, 92%; 2. Me3SiBr, DCM, 74%. c) 1. 2, DIEA, DMAP, DCM, 08C, 69%;
2. NaOH (1m), EtOH, 87%; 3. HCl (3m), 93%. d) 1. HBTU, DIEA, DCM, RT, 72%; 2. Me3SiBr, DCM,
58%. e) 1. 2, DIEA, DMAP, DCM, 08C, 70%; 2. NaOH (1m), EtOH, 94%; 3. HCl (3m), 81%. f) 1. HBTU,
DIEA, DCM, RT, 73%; 2. Me3SiBr, DCM, 44%. g) HBTU, DIEA, DCM, RT, 91%. h) Pd/C, H2, RT, quanti-
tative. i) 1. 2, DIEA, DMAP, DCM, 08C, 74%; 2. NaOH (1m), EtOH, 92%; 3. HCl (3m), 92%. j) HBTU,
DIEA, DCM, RT, 74%. k) Pd/C, H2, RT, quant. l) 1. 2, DIEA, DMAP, DCM, 08C, 60%; 2. NaOH (1m),
EtOH, 86%; 3. HCl (3m), 95%. m) HBTU, DIEA, DCM, RT, 74%. n) Pd/C, H2, RT, quant. o) 1. 2, DIEA,
DMAP, DCM, 08C, 62%; 2. NaOH (1m), EtOH, 89%; 3. HCl (3m), 81%. p) HBTU, DIEA, DCM, RT, 87%.
q) NaOH (1m), EtOH, 74%. r) NH2-NHBoc 3, HBTU, DIEA, DCM, RT, 57%. s) Pd/C, H2, RT, quant. t) 1. 2,
DIEA, DMAP, DCM, 08C, 50%; 2. NaOH (1m), EtOH, 70%; 3. HCl (3m), 86%. DCM=dichloromethane,
DIEA=diisopropylethylamine, DMAP=4-dimethylaminopyridine, HBTU= O-(1H-benzotriazol-1-yl)-
N,N,N’,N,’-tetramethyluronium hexafluorophosphate.
firmed
that
counteranion-
684
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2011, 6, 681 – 689