4772
B. Hulin et al. / Bioorg. Med. Chem. Lett. 15 (2005) 4770–4773
Table 1. DPP-IV inhibitor constants and in vivo activity of compounds 3–10
R
H2N
O
Compound
R
DPP-IV Ki (nM SEM)a
OGTTb % inhibition at 10 mg/kg
69
7
Pyrrolidine
121
128
56
2
4
1
3
3r
3s
4
(R)-3-Fluoropyrrolidine
(S)-3-Fluoropyrrolidine
3,3-Difluoropyrrolidine
(R,R)-3,4-Difluoropyrrolidine
(S,S)-3,4-Difluoropyrrolidine
cis-3,4-Difluoropyrrolidine
Tetrafluoropyrrolidine
Azetidine
28
78
6r
6s
6c
5
504 37
1267 41
61
81
7
3
60
59
8
3350 1080
109 14
9
10
3-Fluoroazetidine
3,3-Difluoroazetidine
70
109
117
4
a Kis are calculated from the IC50s using the Cheng–Prussoff equation for competitive inhibitors (Ref. 16). IC50s were obtained from a standard dose–
inhibition curve.
b Oral Glucose Tolerance Test. A 10 mg/kg oral dose of the compound was administered to fasted mice, followed 15 min later by a 1 g/kg oral glucose
load. Blood glucose levels were measured 30 min later. The effect of the compound is expressed as percent reduction in blood glucose concentration
relative to that measured in animals dosed with an inert vehicle rather than active compound.
DPP-IV, thereby offering alternatives to the usual pyrro-
lidides, thiazolidides, and 3,3-difluoropyrrolidides.
Vehicle control (no inhibitor)
+ Compound 5 (10mg/kg p.o.)
No glucose challenge, no inhibitor
400
300
59% inhibition
References and notes
of glucose
excursion
1. (a) Drucker, D. J. Exp. Opin. Investig. Drugs 2003, 12, 87;
(b) Augustyns, K.; Van der Veken, P.; Haemers, A. Exp.
200
Opin. Ther. Patents 2003, 13, 499; (c) Weber, A. E. J. Med.
Chem. 2004, 47, 4135; (d) Ahren, B.; Schmitz, O. Horm.
Metab. Res. 2004, 36, 867; (e) Deacon, C. F. Diabetes
2004, 53, 2181; (f) Holst, J. J.; Deacon, C. F. Curr. Opin.
Pharmacol. 2004, 4, 589; (g) McIntosh, C. H. S.; Demuth,
glucose excursion
100
0
H.-U.; Pospisilik, J. A.; Pederson, R. Regul. Pept. 2005,
128, 159; (h) Sinclair, E. M.; Drucker, D. J. Diabetes 2005,
12, 146; (i) Mentlein, T. Exp. Opin. Investig. Drugs 2005,
14, 57.
0
5
15
25
35
45
Time (min)
2. (a) Villhauer, E. B.; Brinkman, J. A.; Naderi, G. B.;
Burkey, B. F.; Dunning, B. E.; Prasad, K. J. Med. Chem.
2003, 46, 2774; (b) Ahren, B.; Landin-Olsson, N. M.;
Jansson, P.-A.; Svensson, M. J. Clin. Endocrinol. Metab.
2004, 89, 2078; (c) Barlocco, D. Curr. Opin. Investig. Drugs
2004, 5, 1094; (d) Ahren, B.; Mills, D.; Gomis, R.;
Schweizer, A.; Standl, E. Diabetes Care 2004, 27, 2874.
3. (a) Weber, A. E.; Kim, D.; Beconi, M.; Eiermann, G.;
Fisher, M.; He, H.; Hickey, G.; Jaspal, S.; Leiting, B.;
Lyons, K.; Marsilio, F.; McCann, P.; Moller, D. E.; Patel,
R.; Petrov, A.; Pryor, K.; Sinha Roy, R.; Wu, J. K.;
Wyvratt, M.; Zhang, B. B.; Thornberry, N. A. Abstract
633-P, American Diabetes Association 64th Scientific
Session: Orlando, FL, June 4–8, 2004; (b) Kim, D.; Wang,
L.; Beconi, M.; Eiermann, G. J.; Fisher, M. H.; He, H.;
Hickey, G. J.; Kowalchick, J. E.; Leiting, B.; Lyons, K.;
Marsilio, F.; McCann, M. E.; Patel, R. A.; Petrov, A.;
Scapin, G.; Patel, S. B.; Roy, R. S.; Wu, J. K.; Wyvratt,
M. J.; Zhang, B. B.; Zhu, L.; Thornberry, N. A.; Weber,
A. E. J. Med. Chem. 2005, 48, 141.
inhibitor
glucose
Figure 2. Oral Glucose Tolerance Test of 5 in KK mice at 10 mg/kg.
cult to explain without the benefit of structural informa-
tion. Molecular modeling based on the published DPP-
IV/valine pyrrolidide complex17 failed to elucidate the
binding siteÕs ability to discriminate between cis and
trans vicinal difluoropyrrolidides, as well as the ca. 30-
fold boost of activity upon mono- or difluorination of
the azetidine ring. Fluorine is known to occupy little
more space than hydrogen and to generally increase
lipophilicity by a small degree, however, the magnitude
of the increase in potency and the equivalent potencies
of 9 and 10 make it clear that other effects are at work,
possibly involving interactions between the fluorine
atoms and the residues of the binding cavity.18
In summary, we haveshown that cis-3,4-difluoropyrrolid-
ides, 3,3,4,4-tetrafluoropyrrolidides, and fluorinated aze-
tidides can be easily prepared and are potent inhibitors of
4. (a) Deacon, C. F.; Hughes, T. E.; Holst, J. J. Diabetes
1998, 47, 764; (b) Ahren, B.; Holst, J. J.; Martensson, H.;
Balkan, B. Eur. J. Pharmacol. 2000, 404, 239.