7314 Journal of Medicinal Chemistry, 2009, Vol. 52, No. 22
Kapanda et al.
Al2O3) was suspended in a solution of the (dialkylcarbamoyl)-
methylenedialkylcarbamodithioate (28-29) (2.5 mmol) in 15 mL of
anhydrous dioxane. The reaction was stirred under reflux for 1 h and
filtered. The filtrate was poured onto ice (150 g), and the resulting
mixture was stirred for 30 min. The precipitate was filtered and
recrystallized from 2-propanol-cyclohexane 1:4. A silica gel column
was used for purification with ethyl acetate-hexane 1:4 as eluent.26
(Diethylthiocarbamoyl)methylene Diethylcarbamodithioate (30).
1H NMR (CDCl3) δ (ppm) 4.48 (s, 2H, CH2), 3.78 (q, 4H, 2CH2,
J = 7.20 Hz), 3.74 (q, 4H, 2CH2, J = 7.20 Hz), 1.10 (t, 6H, 2CH3,
J = 7.52 Hz), 1.03 (t, 6H, 2CH3, J = 6.60 Hz). 13C NMR (CDCl3)
δ (ppm) 194.57, 193.60, 49.91, 48.39, 47.24, 46.90, 45.31, 13.88,
12.61, 11.53, 10.98. MS: m/z = 278.98. IR (KBr) (cm-1) 2968,
1502, 1487, 1415, 1357, 1286, 1268,1208, 1141, 1119, 1010, 984, 834.
Synthesis of Dithiobisamine Derivatives (34-36). A solution
of secondary amine (0.5 mmol) in petroleum ether (40 mL)
was precooled to -78 °C before disulfur dichloride (10 μL,
0.125 mmol) was added. The solution was vigorously stirred for
15 min at -78 °C and another 30 min at room temperature.
Water 0.20 mL) was added, and the desired compound was
extracted into the organic phase using diethyl ether (3 ꢀ 10 mL).
The combined organic phase was dried over magnesium sulfate,
filtered, and concentrated under reduced pressure. The com-
pound was purified using silica gel column and ethyl acetate-
hexane 2:8 (v/v) as eluent.27
(6) Karlsson, M.; Contreras, J. A.; Hellman, U.; Tornqvist, H.; Holm,
C. cDNA Cloning, Tissue Distribution and Identification of the
Catalytic Triad of Monoglyceride Lipase: Evolutionary Relation-
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Sensi, S. L.; Kathuria, S; Piomelli, D. Brain Monoglyceride Lipase
Participating in Endocannabinoid Inactivation. Proc. Natl. Acad.
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a Primary Role for Monoacylglycerol Lipase in the Degradation of
the Endocannabinoid 2- Arachidonoylglycerol. Mol. Pharmacol.
2004, 66, 1260–1264.
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Chemistry of Agents Targeting Monoacylglycerol Lipase. Curr.
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Monoglyceride Lipase Inhibitor Evidenced by an Expeditious
MGL Assay. ChemBioChem. 2008, 9, 2704–2710.
(14) Saario, S. M.; Salo, O. M.; Nevalainen, T. Characterization of the
Sulfhydryl-Sensitive Site in the Enzyme Responsible for Hydrolysis
of 2-Arachidonoylglycerol in Rat Cerebellar Membranes. Chem.
Biol. 2005, 12, 649–656.
(15) Long, J. Z.; Li, W.; Booker, L.; Burston, J. J.; Kinsey, S. G.;
Scholburg, J. E.; Pavon, F. J.; Serrano, A. M.; Selley, D. E.;
Parsons, L. H.; Lichtman, A. H.; Cravatt, B. F. Selective Blockade
of 2-Arachidonoylglycerol Hydrolysis Produces Cannabinoid
Behavioral Effects. Nat. Chem. Biol. 2008, 5, 37–44.
N-(2-(Diethylamino)disulfanyl)-N-ethylethanamine (36). 1H
NMR (CDCl3) δ (ppm) 2.78-2.73 (m, 8H, 4CH2), 1.29-1.15
(m, 12H, 4CH3). 13C NMR (CDCl3) δ (ppm) 52.12, 51.88, 51.72,
51.20, 14.20, 13.81, 13.25, 13.18. MS: m/z = 208.32. IR (KBr)
(cm-1) 2974, 1467, 1375, 1360, 1290, 1159, 1060, 901.
Pharmacological Evaluation. hMGL and hFAAH assays were
performed as previously described.16,19 The reversibility assays
(a) by high dilution of the enzyme-inhibitor complex and (b) by
adding the reducing agent DTT were performed as previously
reported.13,16 The plasmids encoding MGL mutants (C208A,
C242A, and C208A/C242A) were obtained following standard
molecular biology procedures, and the expression of these
modified enzymes was performed as described previously.16
(16) Labar, G.; Bauvois, C.; Muccioli, G. G.; Wouters, J.; Lambert, D.
M. Disulfiram is an Inhibitor of Purified Monoacylglycerol lipase,
the Enzyme Regulating 2-Arachidonoylglycerol Signalling. Chem-
BioChem. 2007, 8, 1293–1297.
(17) Shen, M. L.; Lipsky, J. J.; Naylor, S. Role of Disulfiram in the in
Vitro Inhibition of Rat Liver Mitochondrial Aldehyde Dehydro-
genase. Biochem. Pharmacol. 2000, 60, 947–953.
(18) Neelakantan, L. Disulfides. J. Org. Chem. 1958, 23, 938–939.
(19) Labar, G.; Vliet, F. V.; Wouters, J.; Lambert, D. M. A MBP-
FAAH Fusion Protein as a Tool to Produce Human and Rat Fatty
Acid Amid Hydrolase: Expression and Pharmacological Compar-
ison. Amino Acids 2008, 34, 127–133.
(20) Minkkila,A;Savinainen,J.R.;Kasnanen, H.;Xhaard,H.;Nevalainen,
T.; Laitinen, J. T.; Poso, A.; Leppanen, J.; Saario, S. M. Screening
of Various Hormone-Sensitive Lipase Inhibitors as Endocanna-
binoid-Hydrolyzing Enzyme Inhibitors. ChemMedChem 2009, 4,
1253–1259.
Acknowledgment. This work was supported by FNRS
grants (FRSM 3.4.625.07 and FRFC 2.4.654.06), and C.N.
Kapanda is very indebted to the “Fonds Special de Re-
ꢀ
ꢀ
cherche” (Universite Catholique de Louvain) and “Coopera-
tion Technique Belge” for his fellowships. We thank Professor
Gerhard K. E. Scriba (University of Jena, Germany) for the
elemental analyses.
(21) Vandevoorde, S.; Jonsson, K.-O.; Labar, G.; Persson, E.; Lambert,
D. M.; Fowler, C. J. Lack of Selectivity of URB602 for
2-Oleoylglycerol Compared to Anandamide Hydrolysis in vitro.
Br. J. Pharmacol. 2007, 150, 186–191.
(22) Alexander, J. P.; Cravatt, B. F. The Putative Endocannabinoid
Transport Blocker LY2183240 is a Potent Inhibitor of FAAH and
Several Other Brain Serine Hydrolases. J. Am. Chem. Soc. 2006,
128, 9699–9704.
(23) Kapanda, C. N.; Muccioli, G. G.; Labar, G.; Lambert, D. M.;
Poupaert, J. H. Search for Monoglyceride Lipase Inhibitors:
Synthesis and Screening of Arylthioamides Derivatives. Med.
Chem. Res. 2009, 18, 243–254.
Supporting Information Available: pIC50 values of previously
reported MGL inhibitors obtained using recombinant human
MGL and FAAH. description of the synthesized compounds
and pharmacological protocols. This material is available free of
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