Synthesis and structure-toxicity relationships of three new stable analogues of acetyl-seco-hemicholinium-3.

Published

Journal Article

In order to develop and study inhibitors of neuromuscular function which act presynaptically, three stable analogues of acetyl-seco-hemicholinum-3 (AcHC-3,2) were prepared. These analogues have 2-ethoxyethyltrimethylammonium, 4-oxopentyltrimethylammonium, and n-pentyltrimethylammonium moieties substituted for the 2-acetylethyltrimethylammonium (acetylcholine) moieties of AcHC-3 (2) to form the ether 2, ketone 4, and alkane 5 analoggues of AcHC-3 (2). Although AcHC-3 (2) has been shown to undergo deesterification rapidly in basic solutions and slowly at pH 7.4, it has been found to be stable in H2O or D2O under slightly acidic conditions. All of the analogues are stable for extended time under both slightly acidic conditions and at pH 7.4 in H2O or D3O. It has been found that 2 reacts with acetylcholinesterase and butyrylcholinesterase within seconds in H2O at pH7.4. However, deesterification of 2 with subsequent cyclization to the hemiacetal form of hemicholinium-3 (HC-3, 1) is prevented at pH 7.4, possibly by an irreversible binding of 2 to the enzyme. The analogues 3-5, however, do not react under identical conditions. Mouse toxicity studies (LD50) indicate that 2 is approximately as toxic as HC-3 (1), whereas 3, 4, and 5 are 14.2, 23.8, and 43.1 times less toxic, respectively. The toxic effects of 3-5, like 1 and 2, are antagonized by choline but not by neostigmine in mice. Structure-activity relationships of 2-5 are discussed.

Full Text

Duke Authors

Cited Authors

  • Haarstad, VB; Domer, FR; Chihal, DM; Rege, AB; Charles, HC

Published Date

  • June 1, 1976

Published In

Volume / Issue

  • 19 / 6

Start / End Page

  • 760 - 763

PubMed ID

  • 950641

Pubmed Central ID

  • 950641

International Standard Serial Number (ISSN)

  • 0022-2623

Digital Object Identifier (DOI)

  • 10.1021/jm00228a004

Language

  • eng

Conference Location

  • United States