Discovery of a Potent and Highly Selective Dipeptidyl Peptidase IV and Carbonic Anhydrase Inhibitor as "Antidiabesity" Agents Based on Repurposing and Morphing of WB-4101

Abstract

The management of patients with type 2 diabetes mellitus (T2DM) is shifting from cardio-centric to weight-centric or, even better, adipose-centric treatments. Considering the downsides of multidrug therapies and the relevance of dipeptidyl peptidase IV (DPP IV) and carbonic anhydrases (CAs II and V) in T2DM and in the weight loss, we report a new class of multitarget ligands targeting the mentioned enzymes. We started from the known α₁-AR inhibitor WB-4101, which was progressively modified through a tailored morphing strategy to optimize the potency of DPP IV and CAs while losing the adrenergic activity. The obtained compound 12 shows a satisfactory DPP IV inhibition with a good selectivity CA profile (DPP IV IC₅₀: 0.0490 μM; CA II K_i 0.2615 μM; CA VA K_i 0.0941 μM; CA VB K_i 0.0428 μM). Furthermore, its DPP IV inhibitory activity in Caco-2 and its acceptable pre-ADME/Tox profile indicate it as a lead compound in this novel class of multitarget ligands.

Figure 1

Molecular structures of WB-4101.

Figure 2

Docking pose of (S)-WB-4101 in the binding site of DPP IV (PDB ID: 1X70).

Scheme 1. General Synthetic Procedure for Compounds 1–14

Reagents and conditions: (a) triethylamine (TEA), isopropyl alcohol (IPA), reflux, (b) diethyl ether hydrochloride, 0 °C, (c) K₂CO₃, scaffold 40, 43, or 46, N,N-dimethylformamide (DMF), 90 °C, (d) NH₂NH₂·H₂O, MeOH, room temperature (RT), and (e) NH₂NH₂·H₂O, PdO, MeOH, reflux.

Scheme 2. Synthesis of Intermediates 19a–e

Reagents and conditions: (a) 1-bromo-2-chloroethane, tetrabutylammonium bromide (TBAB), NaOH, dichloromethane (DCM), RT; (b) chlorosulfonic acid, DCM, −10 °C; (c) HNRR’, tetrahydrofuran (THF), 0 °C; (d) NaN₃, KI, DMF/H₂O 3:1, 90 °C; and (e) NH₂NH₂·H₂O, PdO, MeOH, reflux.

Scheme 3. Synthesis of the Intermediates 25 and 30a,b

Reagents and conditions: (a) Boc₂O, THF, 0 °C; (b) ethylene carbonate, K₂CO₃, DMF, reflux; (c) MeOH·HCl, 50 °C; (d) MsCl, TEA, DCM, 0 °C; (e) NaN₃, KI, DMF/H₂O 3:1, 90 °C; (f) NH₂NH₂·H₂O, PdO, MeOH, reflux; and (g) RSO₂Cl, TEA, DCM, 0 °C.

Scheme 4. Synthesis of Intermediate 38

Reagents and conditions: (a) SOCl₂, DCM, reflux; (b) N,O-dimethylhydroxylamine, DCM, RT; (c) LiAlH₄, THF, −20 °C; (d) Zn, TBDMSiCl, ethyl bromoacetate, THF, reflux; (e) LiAlH₄, THF, −10 °C; (f) TrtCl, TEA, DCM, RT; (g) PPh₃, diethyl azodicarboxylate (DEAD), diphenylphosphorylazide (DPPA), THF, RT; (h) Amberlist 15, DCM/MeOH, reflux; and(i) MsCl, TEA, DCM, RT.

Scheme 5. Synthesis of Intermediates 40, 43, and 46

Reagents and conditions: (a) NaNO₂, H₂SO₄, H₂O, reflux; (b) DMF-DMA, DMF, RT; (c) NBS, DMF, 0 °C; (d) Br₂, DCM/EtOH, RT; (e) Na, CuI, MeOH, reflux; and (f) DMF-DMA, DMF, RT.

Figure 3

Proposed binding modes of the morphed compounds in the binding site of DPP IV (PDB ID: 1X70). (A) Binding pose of compound (R,S) 11. (B) Superimposition of the third group of compounds: (S,R) 12 (green), (S,R) 13 (orange), and 14 (S,R) (yellow).

Figure 4

(A) Bioavailability radar plot of compounds 11, 12, and WB-4101 (B) using Swiss ADME predictor. Bioavailability radar plot of druglikeness where the pink area characterizes the ideal range for the properties lipophilicity (LIPO), size (SIZE), polarity (POLAR), solubility (INSOLU), saturation (INSATU), and flexibility (FLEX). (B) A boiled-egg graphic where compounds inside the yolk indicate access through the blood–brain barrier (BBB) and those inside white indicate human intestinal absorption (HIA), and blue or red dots represent the prediction of the P-glycoprotein substrate (PGP+) or P-glycoprotein nonsubstrate (PGP−), respectively.

Figure 5

In situ inhibition of the DPP IV activity expressed by nondifferentiated Caco-2 cells after 60 min of treatment. The data are represented as the means ± standard deviation (SD) of three independent experiments, performed in triplicate. Statistical analysis was performed by one-way analysis of variance (ANOVA), followed by Tukey’s post hoc test. ns: not significant; (**), p < 0.01, (****) p < 0.0001; C: control cells. Red bars: sitagliptin, positive control, at 1.0 μM. Blue bars: compound 12.

Figure 6

Metabolic stability in rat, mouse, and human liver microsomes of compound 12.

Figure 7

Fluorescence signals (bars normalized using the Janus Green staining) of human intestinal Caco-2 cells, which internalized compound 12 as a function of time.