title: Pyridophens: binary pyridostigmine-aprophen prodrugs with differential inhibition of acetylcholinesterase, butyrylcholinesterase, and muscarinic receptors.
abstract: A series of "binary prodrugs" called carbaphens,(1) carbamylated derivatives on one or both of the aromatic rings of the muscarinic receptor antagonist aprophen [(N,N-diethylamino)ethyl 2,2-diphenylpropionate], were synthesized to develop binary prophylactic agents against organophosphorus intoxication. As a group, the carbaphens retained the muscarinic receptor antagonist properties of aprophen but also preferentially inhibited butyrylcholinesterase (BChE) in contrast to acetylcholinesterase (AChE). Therefore, a new series of compounds named pyridophens were designed and synthesized to achieve binary prodrugs to preferentially inhibit AChE over BChE, while still retaining the muscarinic receptor antagonism of aprophen. The pyridophens consist of the basic pyridostigmine skeleton combined with the 2,2-diphenylpropionate portion of aprophen by replacement of the diethylamino group. Three compounds, 9 (a tertiary pyridine), 10 (a quaternary pyridine), and 12 (a tertiary tetrahydropyridine), were found to be effective inhibitors of both BChE and AChE. However, 10, N-methyl-3-[[(dimethylamino)carbonyl]oxy]-2-(2'2'-diphenylpropionoxy-methyl)pyridinium iodide, inhibited AChE selectively over BChE, with a bimolecular rate constant similar to pyridostigmine. In contrast to their potent cholinesterase inhibitory activity, all of the pyridophen analogues were less potent antagonists of the muscarinic receptor than aprophen.
authors.affiliation: Division of Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Road, Silver Spring, MD 20910-7500, USA.
authors.forename: Haim
authors.initials: H
authors.lastname: Leader
authors.forename: Alan David
authors.initials: AD
authors.lastname: Wolfe
authors.forename: Peter K
authors.initials: PK
authors.lastname: Chiang
authors.forename: Richard K
authors.initials: RK
authors.lastname: Gordon
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D002091:Butyrylcholinesterase / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018727:Muscarinic Antagonists / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D010666:Phenylpropionates / Q000737:chemistry*; D011355:Prodrugs / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011729:Pyridostigmine Bromide / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D002800:Cholinesterase Inhibitors; D008024:Ligands; D018727:Muscarinic Antagonists; D010666:Phenylpropionates; D011355:Prodrugs; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase; D011729:Pyridostigmine Bromide; C006615:aprofen