Synthesis of 3-Aryl-2,4-dioxo-1,2,3,4-tetrahydroquinazolines and 2-Arylamino-4-oxo-4H-3,1-benzoxazines from MethylN-Aryldithiocarbamates

Efficient Synthesis of 4h-Benzo[d][1,3]oxazin-4-ones from Anthranilic Acids and Aryl Isoselenocyanates

A synthesis in good to excellent yields of 23 4H-benzo[d][1,3]oxazin-4-ones, 18 of which are novel, from monosubstituted anthranilic acids and variously substituted phenyl isoselenocyanates without using any harsh reagents has been developed. The Se powder precipitated during the reaction could be efficiently recycled for the preparation of the aryl isoselenocyanates.

Identification of a bioactive impurity in a commercial sample of 6-methyl-2-p-tolylaminobenzo[d][1,3]oxazin-4-one (URB754)

The compound URB754 was recently identified as a potent inhibitor of the endocannabinoid-deactivating enzyme monoacylglycerol lipase (MGL) by screening of a commercial chemical library. Based on HPLC/MS, NMR and EI/MS analyses, the present paper shows that the MGL-inhibitory activity attributed to URB754 is in fact due to a chemical impurity present in the commercial sample, identified as bis(methylthio)mercurane. Although this organomercurial compound is highly potent at inhibiting MGL (IC50 = 11.9 +/- 1.1 nM), its biological use is prohibited by its toxicity and target promiscuity.

URB754 has no effect on the hydrolysis or signaling capacity of 2-AG in the rat brain

Previous studies indicate that in brain tissue the endocannabinoid 2-AG is inactivated by monoglyceride lipase (MGL)-catalyzed hydrolysis, and a recent report has indicated that MGL activity could be specifically inhibited by URB754 . In the present study, URB754 failed to inhibit 2-AG hydrolysis in rat brain preparations. In addition, brain cryosections were employed to assess whether URB754 could facilitate the detection of 2-AG-stimulated G protein activity. Nevertheless, whereas pretreatment with PMSF readily allowed detection of 2-AG-stimulated G protein activity, URB754 was ineffective. In contrast to previous claims, brain FAAH activity was also resistant to URB754. Thus, in our hands URB754 was not able to block the endocannabinoid-hydrolyzing enzymes and cannot serve as a lead structure for future development of MGL-specific inhibitors.