Structure-activity relations amidines

Amidines. After the initial observation that formamidines are agonists for OA receptors in the firefly (14,15 58), these compounds have been shown to mimic OA in virtually every insect system known to contain OA receptors, including the DUMETi system (59)f the glandular lobe of the corpus cardiacum (60) and the fat body ( ) of the locust, and various CNS adenylate cyclase preparations (26-28). The structure-activity relations of amidines as octopaminergic agonists have been examined in several systems including adenylate cyclase stimulation in the firefly lantern and... 

Kawamoto I, Shimoji Y, Kanno O, Kojima K, Ishikawa K, Matsuyama E, Ashida Y, Shibayama T, Eukuoka T, Ohya S. (2003) Synthesis and structure-activity relationships of novel parenteral carbapenems, CS-023 (R-115685) and related componnds containing an amidine moiety. J Antibiot 56 565-579. 

The only aspect of octopaminergic transmission for which a relatively large amount of structure-activity data is available relates to the properties of OA-receptors themselves. Agonists that stimulate these systems and antagonists that block them, are known and such compounds exist in several structural groups. The three major groups of agonists currently identified are phenylethylamines amidines and imidazolines. 

In the histaminic H2 receptor antagonist series, the classical urea-thiourea-guanidine progression was successfully completed by the use of the V-nitro and V-cyanoguanidines and, later on, by l,l-diamino-2-nitroethylene groups (Fig. 13.19). Cyano amidines and carbamoyl amidines were also used, and structure-activity relationship patterns were rationalized in terms of dipole moment orientation of related bioisosteric groups. ... 

Structurally related complexes are also active initiators for the living polymerization of carbo-diimides (which are isoelectronic to isocyanates).1003 The proposed intermediate for this polymerization process is a metal amidinate (Scheme 29), and the model complex (349) has been reported to be a highly efficient catalyst, polymerizing 500 equivalents of di- -hexylcarbodiimide in less than 10 s. A more hydrolytically robust series of initiators has also been developed, based upon copper(I) and copper(II) amidinates.1004... 

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