Design, synthesis, and evaluation of sugar amino acid based inhibitors of protein prenyl transferases PFT and PGGT-1

Article abstract of DOI:10.1021/jm049927q

Eleven analogues of the C-terminal Ca₁a₂X motif found in natural substrates of the prenyl transferases PFT and PGGT-1 were synthesized and evaluated for their inhibition potency and selectivity against PFT and PGGT-1. Replacement of

Full text of DOI:10.1021/jm049927q

3920
J . Med. Chem. 2004, 47, 3920-3923
The discovery that simple tetrapeptides based on Ca1-
a2X can function as substrate analogue inhibitors of PFT
and PGGT-17 initiated many research activities. This
has resulted in the development of an array of inhibitors
of PFT and, to a lesser extent, PGGT-1.8 At the moment
four PFT inhibitors are in clinical development (phases
I-III).1e,f It was found that the introduction of hydro-
phobic aromatic residues at the a2 position has a bene-
ficial effect on the inhibitory potency against both en-
zymes.9a-f For PFT this is exemplified by the potent and
competitive inhibitor CVFM,10 in which the presence of
phenylalanine at the a2 position is of importance. In line
with these results, it was reported9d,e,11 that Ca1a2L
analogues in which the a1a2 portion was replaced by
dipeptide isosteric 2-aryl-4-aminobenzoic moieties were
effective inhibitors of PGGT-1. The replacement of am-
ide linkages by amine connections in certain Ca1a2X
analogues not only has a beneficial effect on the stability
against proteolytic degradation but also influences the
selectivity of inhibition.12
Design , Syn th esis, a n d Eva lu a tion of Su -
ga r Am in o Acid Ba sed In h ibitor s of P r o-
tein P r en yl Tr a n sfer a ses P F T a n d P GGT-1
Farid El Oualid,†,‡ Brigitte E. A. Burm,†,‡
Ingrid M. Leroy,§ Louis H. Cohen,§
J acques H. van Boom,† Hans van den Elst,†
Herman S. Overkleeft,† Gijs A. van der Marel,*,† and
Mark Overhand*,†
Leiden Institute of Chemistry, Gorlaeus Laboratories,
Leiden University, P.O. Box 9502, 2300 RA Leiden,
The Netherlands, and TNO Prevention and Health,
Gaubius Laboratory, P.O. Box 2215,
2301 CE Leiden, The Netherlands
Received J anuary 26, 2004
Abstr a ct: Eleven analogues of the C-terminal Ca1a2X motif
found in natural substrates of the prenyl transferases PFT and
PGGT-1 were synthesized and evaluated for their inhibition
potency and selectivity against PFT and PGGT-1. Replacement
of the central dipeptide part a1a2 by a benzylated sugar amino
acid resulted in a good and highly selective PFT inhibitor (8,
IC50 ) 250 ( 20 nM). The methyl ester of 8 (13) selectively
inhibited protein farnesylation in cultured cells.
As part of a program aimed at the development of
novel inhibitors of both PFT and PGGT-1, we recently
reported13,14 a new type of Ca1a2X analogue in which a
sugar amino acid (SAA) is incorporated as a replacement
of the central dipeptide a1a2. By virtue of the intrinsic
properties of SAAs15a-c (i.e., inducing a â-turn15d or an
extended conformation) and the number and spatial
orientation of the functionalities appended to the sugar
core, the inhibitory action can be substantially en-
hanced. In line with this, a new set of inhibitors can be
obtained by the introduction of an aromatic functionality
on the peptidomimetic part. Moreover, our recently
developed16 synthesis of amino acid/carbohydrate con-
jugates via the Fukuyama-Mitsunobu glycosylation of
amino acid derived o-nitrobenzenesulfonamides offered
the opportunity to evaluate the inhibitory potency and
selectivity of Ca1a2X analogues having an amine bond
between the peptidomimetic and the C-terminal residue.
Protein farnesyl transferase1 (PFT) and protein gera-
nylgeranyl transferase-12 (PGGT-1) (both protein prenyl
transferases) catalyze the transfer of isoprenoid lipids
from the corresponding pyrophosphates to cysteine resi-
dues at the C termini of precursor proteins that in the
mature state are key factors in various biological pro-
cesses. One of the most studied prenylated proteins is
Ras, a small GTP-binding protein that is an important
switch in signal transduction pathways that mediate
growth factor stimulated cell proliferation. The wide in-
terest in Ras is based on the existence of various forms
of mutated Ras proteins that are present in (and par-
tially responsible for the proliferation of) 30-40% of all
human tumors.3 Isoprenylation is the first and essential
step in a series of post-translational modification events
that lead to mature Ras. Inhibition of isoprenylation of
oncogenic Ras prevents localization at the cell mem-
brane, thereby prohibiting cell transformation.
PFT attaches a farnesyl group to proteins that contain
the C-terminal Ca1a2X motif (C ) cysteine, a1a2 ) any
aliphatic amino acid, X ) methionine or serine), while
PGGT-1 catalyzes the geranylgeranylation of the same
motif but with X as leucine. Initially, PFT was consid-
ered as the main pharmacological target aimed at
disabling Ras functioning for the development of anti-
tumor agents. However, it was recently demonstrated
that upon inhibion of PFT the most abundant human
oncogenic Ras protein, Ras K-4B, can be geranylgera-
nylated by PGGT-1,4 resulting in a modified protein
with comparable transforming potential as the farne-
sylated protein.5 This finding underscores the impor-
tance of PGGT-1, next to PFT, as a therapeutic target
in cancer research.1,6
We report the synthesis of novel inhibitors of the pren-
ylating enzymes PFT and PGGT-1 containing benzyla-
ted SAA having a 1,5-trans (i.e., R) or a 1,5-cis (i.e., â) sub-
stituted sugar core. The Ca1a2L analogues (1-4 and the
controls 11 and 12,13b Scheme 3) were designed to in-
hibit PGGT-1, while the corresponding Ca1a2M analog-
ues (5-8) were projected to inhibit PFT. Sulfoxides 9
and 10 were obtained as side products in a deprotection
step. All compounds were evaluated for their inhibit-
ory potency and selectivity in a PFT and PGGT-1 enzyme
bioassay. The effect of 13 (methyl ester of 8) on the pre-
nylation of proteins was investigated in cultured cells.
Epimeric alcohols 16r and 16â, required for the pre-
paration of the here-reported Ca1a2X analogues, are
readily available from tri-O-acetyl-D-glycal.17 The syn-
thesis of the fully protected amine precursors (19r,â and
20r,â) is exemplified by the conversion of 16r into 19r
and 20r (Scheme 1). Thus, treatment of 16r with o-Ns-
Leu-OMe (14)18a or o-Ns-Met-OMe (15)18b and PPh3/
DEAD gave, after removal of the nosyl group, the dimer
17r or 18r, respectively, in good yield. The Boc group
was removed, and the corresponding amine was con-
densed with Fmoc-Cys(StBu)-OH, furnishing Ca1a2X
* To whom correspondence should be addressed. For G.A.v.d.M:
phone, 071-527-4208; e-mail, marel_g@chem.leidenuniv.nl; fax, 071-
527-4307. For M.O.: phone, 071-527-4483; e-mail, overhand@chem.
leidenuniv.nl; fax, 071-527-4307.
† Leiden University.
‡ Both authors contributed equally to this study.
§ Gaubius Laboratory.
10.1021/jm049927q CCC: $27.50 © 2004 American Chemical Society
Published on Web 06/24/2004

Letters
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 16 3921
Sch em e 3. Synthesis 1-8, 11, and 13a
Sch em e 1. Synthetic Scheme for 19r and 20ra
a
Reagents and conditions: (i) (a) o-Ns-Leu-OMe (14) or o-Ns-
Met-OMe (15), PPh3, DEAD, THF; (b) K2CO3, PhSH, CH3CN, 50
°C (17r, 65%; 18r, 81%, two steps); (ii) TFA/DCM 1/1 v/v, iPr3SiH
or Et3SiH; (iii) Fmoc-Cys(StBu)-OH, BOP, N-ethylmorpholine,
DMF (19r, 40%; 20r, 47%, two steps).
a
Sch em e 2. Synthetic Scheme for 23â and 24âa
Reagents and conditions: (i) (a) MeOH/1,4-dioxane/4 M NaOH;
(b) RP-HPLC purification; (ii) (a) Pd/C, H2, EtOH/CHCl3 (100%);
(b) TFA/DCM 1/1 v/v, iPr3SiH; (c) Fmoc-Cys(StBu)-OH, BOP,
N-ethylmorpholine, DMF (52%, two steps); (iii) 20% piperidine in
DMF (13, 81%). For 7 and 8 the reaction was performed under
argon with freshly distilled 1,4-dioxane (benzophenone ketyl).
Ta ble 1. IC50 Values of 1-11 and Reference Compounds CVIM
and CVIL in PFT and PGGT-1 Bioassaya,b
IC50 (µM)a
IC50 (µM)a
compd
PFT
PGGT-1
compd
PFT
PGGT-1
1
2
5
6
3
4
7
∼1000
>1000
∼1000
>1000
321 ( 18
57 ( 18
42 ( 6
270 ( 122
464 ( 147
311 ( 94
500 ( 81
206 ( 34
14 ( 6
8
9
10
11
CVIM
CVIL
0.25 ( 0.02
91 ( 14
2.2 ( 0.6
>1000
>1000
521 ( 75
>1000
261 ( 55
0.42 ( 0.05
ndc
ndc
4.4 ( 0.2
aReagents and conditions: (i) RuCl3‚3H2O, K2S2O8, 1 M KOH
or TEMPO, bisiodobenzene diacetate, DCM/H2O (SAA, 100%); (ii)
HCl‚H-Leu-OMe, BOP/DiPEA or HCl‚H-Met-OMe, EDC, HOBt,
DMF (21â, 98%; 22â, 83%); (iii) TFA/DCM 1/1 v/v, iPr3SiH or
Et3SiH; (iv) Fmoc-Cys(StBu)-OH; for 23â, BOP/HOBt, DiPEA; for
24â, EDC/HOBt, DMF (23â, 85%; 24â, 79%, two steps).
48 ( 11
a
IC50: concentration of compound required to inhibit by 50%
the PFT or PGGT-1 catalyzed incorporation of [3H]FPP or [3H]G-
GPP, respectively. All IC50 values are the mean of three determi-
nations. One determination involves performing the assay at five
concentrations of compound. By use of a mathematical function
fitting the concentration-inhibition curve, the IC50 value was
analogues 19r and 20r. Starting from 16â, the corre-
sponding 1,5-cis-amine precursors were obtained. The
synthesis of the fully protected amide precursors (23r,â
and 24r,â) is exemplified by the conversion of 16â into
compounds 23â and 24â (Scheme 2). Hence, oxidation
of 16â with RuCl3‚3H2O19 or TEMPO/bisiodobenzene
diacetate20 gave the corresponding SAA. Subsequent
condensation with HCl‚H-Leu-OMe or HCl‚H-Met-OMe
yielded 21â and 22â, respectively. Deprotection of the
Boc group and condensation with Fmoc-Cys(StBu)-OH
afforded 23â and 24â. Employing 16r furnished the
corresponding 1,5-trans-Ca1a2X analogues.
Target 1-8 were obtained by treatment of the fully
protected precursors with Tesser’s base (MeOH/dioxane/
4 M NaOH, 15/4/1, v/v/v) to effect simultaneous hydroly-
sis of the ester and removal of the Fmoc protective group
(Scheme 3). The crude compounds were characterized
by LC-MS and purified by RP-HPLC. For 24r and 24â
the applied deprotection conditions resulted in the form-
ation of oxidized side products that were identified by
NMR and mass spectrometry as the corresponding sul-
foxides 9 and 10 (Scheme 3). Isolation of these products
allowed evaluation of their biological activity. Fortunate-
ly, base-mediated deprotection under stringent non-
aerobic conditions allowed isolation of the desired 7 and
8.
b
determined. For CVIM the reported IC50 for PFT in vitro varies
between 150 and 200 nM. For CVIL the reported IC50 for PGGT-1
varies between 2 and 11 µM. c nd ) not determined.
Removal of the benzyl group in 17â (Pd/C, H2) fol-
lowed by the same sequence of reactions as described
for the synthesis of 1 allowed us to evaluate amine 11
(Scheme 3) and to compare it with its previously re-
ported amide analogue 12 (IC50{PGGT-1} ≈ 1000 µM).13b
1-11 (Scheme 3) were evaluated for their in vitro
inhibitory activity against PFT and PGGT-1 following
previously described procedures.14c,d The thio tert-butyl
protective group in the cysteine residue of 1-11 is
cleaved under the conditions of the assay (dithiothreitol,
Tris buffer, pH 7.4). As a reference, we also evaluated
the known tetrapeptides CVIM and CVIL12 in our assay.
In Table 1 all determined IC50 values are summarized.
8, having a 1,5-cis configuration of the SAA core,
proved to be a good (IC50 ) 250 ( 20 nM) and selective
PFT inhibitor. Furthermore, 8 shows a 1000- to 4000-
fold improvement in potency compared to our previously
reported13a PFT inhibitors and was found to be slightly
more active than the known12 tetrapeptide inhibitor
CVIM. When 8 and 7 (having a 1,5-trans configuration)
are compared, it becomes clear that the stereochemical

3922 J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 16
Letters
steres of the a1a2 part and evaluated their inhibitory
potency in a PFT and PGGT-1 bioassay. Structure-acti-
vity relationship analysis demonstrates that the ster-
eochemistry of the SAA residue has a pronounced effect
on inhibition potency and selectivity. 8, having a 1,5-
cis configuration of the SAA core and X ) methionine,
was shown to be the most potent and selective PFT
inhibitor in this series. Diastereoisomer 7 is a modest
active dual inhibitor of both enzymes. 4, having a 1,5-
cis SAA configuration and X ) leucine, was also found
to be a modest active dual inhibitor.27 In addition, while
8 was not active in intact cells, the corresponding methyl
ester 13 was shown to selectively inhibit protein farne-
sylation in intact Met-18b-2 cells.
F igu r e 1. In vivo evaluation of TR006, 8, and 13. Met-18b-2
cells were treated with [3H]mevalonate and simvastatin and
in the absence of compound (lane 1): with TR006 (lane 2, 100
µM); 8 (lane 3, 100 µM); 13 (lane 4, 100 µM). Monolayers of
cells were dissolved in detergent solution and subjected to
electrophoresis and autoradiography (see Supporting Informa-
tion).
Ack n ow led gm en t. This research was supported by
The Netherlands Technology Foundation (CW-STW).
The authors thank Kees Erkelens and Fons Lefeber
(NMR), Nico Meeuwenoord (chromatography), and Bertil
Hofte (HR-MS).
Su p p or tin g In for m a tion Ava ila ble: Spectroscopic data
and experimental procedures. This material is available free
of charge via the Internet at http://pubs.acs.org.
Refer en ces
F igu r e 2. Compound TR006.
(1) (a) Leonard, D. M. Ras farnesyltransferase: a new therapeutic
target. J . Med. Chem. 1997, 40, 2971-2990. (b) Long, S. B.;
Casey, P. J .; Beese, L. S. Reaction pathway of protein farnesyl-
transferase at atomic resolution. Nature 2002, 419, 645-650.
(c) Long, S. B.; Hancock, P. J .; Kral, A. M.; Hellinga, H. W.;
Beese, L. S. The crystal structure of human protein farnesyl-
transferase reveals the basis for inhibition by CaaX tetrapeptides
and their mimetics. Proc. Natl. Acad. Sci. U.S.A., 2001, 98,
12948-12953. (d) Prendergast, G. C.; Oliff, A. Farnesyltrans-
ferase inhibitors: antineoplastic properties, mechanisms of
action, and clinical prospects. Semin. Cancer Biol. 2000, 10,
443-452. (e) Mazieres, J .; Pradines, A.; Favre, G. Perspectives
on farnesyl transferase inhibitors in cancer therapy. Cancer Lett.
2004, 206, 159-167. (f) Bell, I. M. Inhibitors of farnesyltrans-
ferase: a rational approach to cancer chemotherapy? J . Med.
Chem. 2004, 47, 1869-1878.
identity of the SAA is important with respect to potency
and selectivity.
For PGGT-1, 4 was found to be the most active in-
hibitor (IC50 ) 14 µM). 4, which only differs from 8 in
its X amino acid, shows no high selectivity for either
enzyme.21 Comparing 1213b with 4 shows that enhanced
hydrophobicity at the a2 position has a positive effect
on the inhibitory potency. Having an amine linkage be-
tween the dipeptide isostere and the X amino acid (1,
2, 5, and 6) proves to be detrimental for the inhibition
of both enzymes, in particular for PFT.22 However, 11
is ∼4 times more active against PGGT-1 than its amide
analogue 12. Although introduction of a sulfoxide func-
tionality (9, 10) leads to a decrease in inhibitory potency,
this modification is more tolerated by PFT than PGGT-
1.23a This is in analogy with results reported by Manne
and co-workers23b who observed that replacement of the
methionine by polar residues (e.g., a carboxamide or
sulfone) retained inhibitory potency against PFT and
to a lesser extent against PGGT-1.
To evaluate whether 8 is able to inhibit protein
farnesylation in vivo (Met-18b-2 cells),24 its methyl ester
(13) was synthesized to facilitate cellular uptake.25 As
illustrated in Figure 1, incubation with [3H]mevalonate
resulted in several labeled prenylated proteins that can
be roughly divided into farnesylated proteins at molec-
ular weights of about 46-80 kDa and geranylgeranyl-
ated proteins at about 22-28 kDa.26
(2) Taylor, J . S.; Reid, T. S.; Terry, K. L.; Casey, P. J .; Beese, L. S.
Structure of mammalian protein geranylgeranyltransferase type-
I. EMBO J . 2003, 22, 5963-5974 and references therein.
(3) (a) Grand, R. J . A.; Owen, D. The biochemistry of Ras p21.
Biochem. J . 1991, 279, 609-631. (b) Barbacid, M. Ras genes.
Annu. Rev. Biochem. 1987, 56, 779-827. (c) Seabra, M. C.
Membrane association and targeting of prenylated Ras-like
GTPases. Cell. Signalling 1998, 10, 167-172. (d) Lowy, D. R.;
Willumsen, B. M. Function and regulation of Ras. Annu. Rev.
Biochem. 1993, 62, 851-891. (e) Pells, S.; Divjak, M.; Ro-
manowski, P.; Impey, H.; Hawkins, N. J .; Clarke, A. R.; Hooper,
M. L.; Williamson, D. J . Developmentally-regulated expression
of murine K-ras isoforms. Oncogene 1997, 15, 1781-1786. (f)
Duursma, A. M.; Agami, R. Ras interference as cancer therapy.
Semin. Cancer Biol. 2003, 13, 267-273.
(4) (a) Sebti, S. M.; Hamilton, A. D. Farnesyltransferase and
geranylgeranyltransferase
I inhibitors and cancer therapy:
lessons from mechanism and bench-to-bedside translational
studies. Oncogene 2000, 19, 6584-6594. (b) Ellis, C. A.; Clark,
G. The importance of being K-Ras. Cell. Signalling 2000, 12,
425-434.
(5) J ames, G.; Goldstein, J . L.; Brown, M. S. Resistance of K-RasBV12
proteins to farnesyltransferase inhibitors in Rat1 cells. Proc.
Natl. Acad. Sci. U.S.A. 1996, 93, 4454-4458.
While incubation with 8 (lane 3) did not influence the
prenylation pattern, 13 (lane 4) inhibited the incorpora-
tion of mevalonate into the higher molecular weight
bands, indicating that protein farnesylation was strongly
decreased. The 21-28 kDa bands did not change, sup-
porting the specificity of the inhibition. As a positive
control, TR006 (Figure 2), a potent inhibitor of both
PFT14d and GGPP synthase14e was shown to decrease
the prenylation of both the higher and lower molecular
weight proteins (lane 2).
(6) (a) Pruitt, K.; Der, C. J . Ras and Rho regulation of the cell cycle
and oncogenesis. Cancer Lett. 2001, 171, 1-10. (b) Boettner, B.;
Van Aelst, L. The role of RhoB GTPases in disease development.
Gene 2002, 286, 155-174. (c) Di Paolo, A.; Danesi, R.; Caputo,
S.; Macchia, M.; Lastella, M.; Boggi, U.; Mosca, F.; Marchetti,
A.; Del Tacca, M. Inhibition of protein farnesylation enhances
the chemotherapeutic efficacy of the novel geranylgeranyltrans-
ferase inhibitor BAL9611 in human colon cancer cells. Br. J .
Cancer 2001, 84, 1535-1543.
(7) Reiss, Y.; Goldstein, J . L.; Seabra, M. C.; Casey, P. J .; Brown,
M. S. Inhibition of purified p21Ras farnesyl-protein transferase
by Cys-AAX tetrapeptides. Cell 1990, 62, 81-88.
(8) Eskens, F. A. L. M.; Stoter, G.; Verweij, J . Farnesyl transferase
inhibitors: current developments and future perspectives. Can-
cer Treat. Rev. 2000, 26, 319-332. See further references cited
in ref 13b.
In summary, we have synthesized novel Ca1a2X
analogues containing benzylated SAA dipeptide iso-

Letters
(9) (a) Ahmed, S.; Majeux, N.; Caflisch, A. Hydrophobicity and
J ournal of Medicinal Chemistry, 2004, Vol. 47, No. 16 3923
Schweizer, F. Glycosamino acids: building blocks for combina-
torial synthesissimplications for drug discovery. Angew. Chem.,
Int. Ed. 2002, 41, 230-253. (c) Chakraborty, T. K.; Ghosh, S.;
J ayaprakash, S. Sugar amino acids and their uses in designing
bioactive molecules. Curr. Med. Chem. 2002, 9, 421-435. (d)
Aguilera, B.; Siegal, G.; Overkleeft, H. S.; Meeuwenoord, N. J .;
Rutjes, F. P. J . T.; van Hest, J . C. M.; Schoemaker, H. E.; van
der Marel, G. A.; van Boom, J . H.; Overhand, M. Synthesis and
structural analysis of a â-hairpin peptide containing a sugar
amino acid. Eur. J . Org. Chem. 2001, 1541-1547. (e) Kriek, N.
M. A. J .; van der Hout, E.; Kelly, P.; van Meijgaarden, K. E.;
Geluk, A.; Ottenhoff, T. H. M.; van der Marel, G. A.; Overhand,
M.; van Boom, J . H.; Valentijn, A. R. P. M.; Overkleeft, H. S.
Synthesis of novel tetrahydropyran-based dipeptide isosters by
Overman rearrangement of 2,3-didehydroglycosides. Eur. J . Org.
Chem. 2003, 2418-2427.
functionality maps of farnesyltransferase. J . Mol. Graphics
Modell. 2001, 19, 307-317. (b) Breslin, M. J .; deSolms, S. J .;
Giuliani, E. A.; Stokker, G. E.; Graham, S. L.; Pompliano, D. L.;
Mosser, S. D.; Hamilton, K. A.; Hutchinson, J . H. Potent, non-
thiol inhibitors of farnesyltransferase. Bioorg. Med. Chem. Lett.
1998, 8, 3311-3316. (c) Houssin, R.; Pommery, J .; Salau¨n, M.-
C.; Deweer, S.; Goossens, J .-F.; Chavatte, P.; He´nichart, J .-P.
Design, synthesis, and pharmacological evaluation of new far-
nesyl protein transferase inhibitors. J . Med. Chem. 2002, 45,
533-536. (d) Gwaltney, S. L., II; O’Connor, S. J .; Nelson, L. T.
J .; Sullivan, G. M.; Imade, H.; Wang, W.; Hasvold, L.; Li, Q.;
Cohen, J .; Gu, W.-Z.; Tahir, S. K.; Bauch, J .; Marsh, K.; Ng, S.-
C.; Frost, D. J .; Zhang, H.; Muchmore, S.; J akob, C. G.; Stoll,
V.; Hutchins, C.; Rosenberg, S. H.; Sham, H. L. Aryl tetrahy-
dropyridine inhibitors of farnesyltransferase: glycine, phenyla-
lanine and histidine derivatives. Bioorg. Med. Chem. Lett. 2003,
13, 1359-1362. (e) Qian, Y.; Marugan, J . J .; Fossum, R. D.; Vogt,
A.; Sebti, S. M.; Hamilton, A. D. Probing the hydrophobic pocket
of farnesyltransferase: aromatic substitution of CAAX peptido-
mimetics leads to highly potent inhibitors. Bioorg. Med. Chem.
1999, 7, 3011-3024. (f) Qian, Y.; Vogt, A.; Vasudevan, A.; Sebti,
S. M.; Hamilton, A. D. Selective inhibition of type-I geranylgera-
nyltransferase in vitro and in whole cells by CAAL peptidomi-
metics. Bioorg. Med. Chem. 1998, 6, 293-299.
(16) Turner, J . J .; Fillipov, D. V.; Overhand, M.; van der Marel, G.
A.; van Boom, J . H. Synthesis of novel amino acid carbohydrate
hybrids via Mitsunobu glycosylation of nitrobenzenesulfona-
mides. Tetrahedron Lett. 2001, 42, 5763-5767.
(17) See Supporting Information for full details.
(18) (a) Piro´, J .; Rubiralta, M.; Giralt, E.; Diez, A. Solid phase
synthesis of enantiomerically pure polyhydroxyvalerolactams.
Tetrahedron Lett. 2001, 42, 871-873. (b) Albanese, D.; Landini,
D.; Lupi, V.; Penso, M. N-monoalkylation of R-amino acid esters
under solid-liquid PTC conditions. Eur. J . Org. Chem. 2000,
1443-1449.
(19) (a) Varma, R. S.; Hogan, M. E. Ruthenium tetraoxide catalyzed
oxidation of nucleosides: A facile synthesis of 5′-carboxylic acid
derivatives. Tetrahedron Lett. 1992, 33, 7719-7720. (b) Green,
G.; Griffith, W. P.; Hollinshead, D. M.; Ley, S. V.; Schroder, M.
Oxo complexes of ruthenium(VI) and (VII) as organic oxidants.
J . Chem. Soc., Perkin Trans. 1 1984, 681-686.
(10) Leftheris, K.; Kline, T.; Natarajan, S.; DeVirgilio, M. K.; Cho,
Y. H.; Pluscec, J .; Ricca, C.; Robinson, S.; Seizinger, B. R.;
Manne, V.; Meyers, C. A. Peptide based P21RAS farnesyl trans-
ferase inhibitors: systematic modification of the tetrapeptide
CA1A2X motif. Bioorg. Med. Chem. Lett. 1994, 4, 887-892.
(11) Vasudevan, A.; Qian, Y.; Vogt, A.; Blaskovich, M. A.; Ohkanda,
J .; Sebti, S. M.; Hamilton, A. D. Potent, highly selective, and
non-thiol inhibitors of protein geranylgeranyltransferase-I. J .
Med. Chem. 1999, 42, 1333-1340.
(12) (a) Graham, S. L.; deSolms, S. J .; Giuliani, E. A.; Kohl, N. E.;
Mosser, S. D.; Oliff, A. I.; Pompliano, D. L.; Rands, E.; Breslin,
M. J .; Deana, A. A.; Garsky, V. M.; Scholz, T. H.; Gibbs, J . B.;
Smith, R. L. Pseudopeptide inhibitors of Ras farnesyl-protein
transferase. J . Med. Chem. 1994, 37, 725-732. (b) Wai, J . S.;
Bamberger, D. L.; Fisher, T. E.; Graham, S. L.; Smith, R. L.;
Gibbs, J . B.; Mosser, S. D.; Oliff, A. I.; Pompliano, D. L.; Rands,
E.; Kohl, N. E. Synthesis and biological activity of Ras farnesyl
protein transferase inhibitors. Tetrapeptide analogs with amino
methyl and carbon linkages. Bioorg. Med. Chem. 1994, 2, 939-
947. (c) Reiss, Y.; Stradley, S. J .; Gierasch, L. M.; Brown, M. S.;
Goldstein, J . L. Sequence requirement for peptide recognition
by rat-brain p21Ras protein farnesyltransfearse. Proc. Natl.
Acad. Sci. U.S.A. 1991, 88, 732-736.
(13) (a) Overkleeft, H. S.; Verhelst, S. L.; Pieterman, E.; Meeuwe-
noord, N.; Overhand, M.; Cohen, L. H.; van der Marel, G. A.;
van Boom, J . H. Design and synthesis of a protein:farnesyl-
transferase inhibitor based on sugar amino acids. Tetrahedron
Lett. 1999, 40, 4103-4106. (b) El Oualid, F.; Bruining, L.; Leroy,
I. M.; Cohen, L. H.; van Boom, J . H.; van der Marel, G. A.;
Overkleeft, H. S.; Overhand, M. Synthesis and biological evalu-
ation of protein:geranylgeranyltransferase I inhibitors based on
the CaaX box: incorporation of sugar amino acids as dipeptide
isosters. Helv. Chim. Acta 2002, 85, 3455-3472.
(14) (a) Overhand, M.; Pieterman, E.; Cohen, L. H.; Valentijn, A. R.
P. M.; van der Marel, G. A.; van Boom, J . H. Synthesis of
triphosphonate analogues of farnesyl pyrophosphate. Inhibitors
of squalene synthase and protein:farnesyl transferase. Bioorg.
Med. Chem. Lett. 1997, 7, 2435-2440. (b) Overhand, M.;
Stuivenberg, H. R.; Pieterman, E.; Cohen, L. H.; van Leeuwen,
R. E. W.; Valentijn, A. R. P. M.; Overkleeft, H. S.; van der Marel,
G. A.; van Boom, J . H. Inhibitors of protein:farnesyl transferase
and protein:geranylgeranyl transferase I: synthesis of homolo-
gous diphosphonate analogues of isoprenylated pyrophosphate.
Bioorg. Chem. 1998, 26, 269-282. (c) Cohen, L. H.; Pieterman,
E.; van Leeuwen, R. E. W.; Pascale Negre-Aminou, J . D.;
Valentijn, A. R. P. M.; Overhand, M.; van der Marel, G. A.; van
Boom, J . H. Inhibition of human smooth muscle cell proliferation
in culture by farnesyl pyrophosphate analogues, inhibitors of in
vitro protein:farnesyl transferase. Biochem. Pharmacol. 1999,
57, 365-373. (d) Cohen, L. H.; Valentijn, A. R. P. M.; Rooden-
burg, L.; van Leeuwen, R. E. W.; Huisman, R. H.; Lutz, R. J .;
van der Marel, G. A.; van Boom, J . H. Different analogues of
farnesyl pyrophosphate inhibit squalene synthase and protein:
farnesyltransferase to different extents. Biochem. Pharmacol.
1995, 49, 839-845. (e) Diminished production of GGPP results
in lesser formation of geranylgeranylated proteins: Cohen, L.
H.; Pieterman, E.; van Leeuwen, R. E. W.; Burm, B. E. A.; van
der Marel, G. A.; van Boom, J . H. Inhibitors of prenylation of
Ras and other G-proteins and their application as therapeutics.
Biochem. Pharmacol. 2000, 60, 1061-1068.
(20) (a) Epp, J . B.; Widlanski, T. S. Facile preparation of nucleoside-
5′-carboxylic Acids. J . Org. Chem. 1999, 64, 293-295. (b) De
Mico, A.; Margarita, R.; Parlanti, L.; Vescovi, A.; Piancatelli, G.
A versatile and highly selective hypervalent iodine (III)/2,2,6,6-
tetramethyl-1-piperidinyloxyl-mediated oxidation of alcohols to
carbonyl compounds. J . Org. Chem. 1997, 62, 6974-6977.
(21) The C-terminal tetrapeptide sequence of the small G-protein
rap2b, CVIL, is a nonselective inhibitor of PFT (IC50 ) 16.7 µM)
and PGGT-1 (IC50 ) 11.3 µM). On the other hand, CVIM is more
selective for PFT (IC50 ) 0.17 µM) and PGGT-1 (IC50 ) 49 µM).
See also ref 12.
(22) The amide bond connecting the a2 and X residues plays an im-
portant role in PFT and PGGT-1: (a) Strickland, C. L.; Windsor,
W. T.; Syto, R.; Wang, L.; Bond, R.; Wu, Z.; Schwartz, J .; Le, H.
V.; Beese, L.; Weber, P. C. Crystal structure of farnesyl protein
transferase complexed with a CaaX peptide and farnesyl diphos-
phate analogue. Biochemistry 1998, 37, 16601-16611. (b) Park,
H.-W.; Boduluri, S. R.; Moomaw, J . F.; Casey, P. J .; Beese, L. S.
Crystal structure of farnesyl protein transferase at 2.25 ang-
strom resolution. Science 1997, 275, 1800-1804. See also ref 2.
(23) (a) Burns, C. J .; Guitton, J .-D.; Baudoin, B.; Lelie`vre, Y.;
Duchesne, M.; Parker, F.; Fromage, N.; Commerc¸on, A. Novel
conformationally extended naphthalene-based inhibitors of far-
nesyltransferase. J . Med. Chem. 1997, 40, 1763-1767. (b)
Leftheris, K.; Kline, T.; Vite, G. D.; Cho, Y. H.; Bhide, R. S.;
Patel, D. V.; Patel, M. M.; Schmidt, R. J .; Weller, H. N.;
Andahazy, M. L.; Carboni, J . M.; Gullo-Brown, J . L.; Lee, F. Y.
F.; Ricca, C.; Rose, W. C.; Yan, N.; Barbacid, M.; Hunt, J . T.;
Meyers, C. A.; Seizinger, B. R.; Zahler, R.; Manne, V. Develop-
ment of highly potent inhibitors of Ras farnesyltransferase
possessing cellular and in vivo activity. J . Med. Chem. 1996,
39, 224-236.
(24) Faust, J .; Krieger, M. Expression of specific high capacity
mevalonate transport in a Chinese hamster ovary cell variant.
J . Biol. Chem. 1987, 262, 1996-2004.
(25) Esters are used to enhance the membrane permeability of these
types of compounds. After entering the cell, hydrolases can
transform the methyl ester to the carboxylic acid functionality,
thought to be required for binding to PFT.
(26) Coxon, F. P.; Helfrich, M. P.; Larijani, B.; Muzylak, M.; Dunford,
J . E.; Marshall, D.; McKinnon, A. D.; Nesbitt, S. A.; Horton, M.
A.; Seabra, M. C.; Ebetino, F. H.; Rogers, M. J . Identification of
a novel phosphonocarboxylate inhibitor of Rab geranylgeranyl
transferase that specifically prevents Rab prenylation in osteo-
clasts and macrophages. J . Biol. Chem. 2001, 276, 48213-48222.
(27) Dinsmore, C. J .; Zartman, C. B.; Bergman, J . M.; Abrams, M.
T.; Buser, C. A.; Culberson, J . C.; Davide, J . P.; Ellis-Hutchings,
M.; Fernandes, C.; Graham, S. L.; Hartman, G. D.; Huber, H.
E.; Lobell, R. B.; Mosser, S. D.; Robinson, R. G.; Williams, T. M.
Macrocyclic piperazinones as potent dual inhibitors of farnesyl-
transferase and geranylgeranyltransferase-I. Bioorg. Med. Chem.
Lett. 2004, 14, 639-643 and references therein.
(15) (a) Gruner, S. A. W.; Locardi, E.; Lohof, E.; Kessler, H.
Carbohydrate-based mimetics in drug design: sugar amino acids
and carbohydrate scaffolds. Chem. Rev. 2002, 102, 491-514. (b)
J M049927Q