Expeditious synthesis and biological evaluation of novel 2,N6-disubstituted 1,2-dihydro-1,3,5-triazine-4,6-diamines as potential antimalarials
摘要:
A small set of novel 2,N-6-disubstituted 1,2-dihydro-1,3,5-triazine-4,6-diamines was prepared possessing a flexible tether between the exocyclic nitrogen bonded to C-6 of the 1,2-dihydro-1,3,5-triazine-4,6-diamine heterocycle and the distal aryl ring. Three zones were varied in this series of compounds, namely the nature of the substituent(s) on C-2; the nature of the substituent(s) on the distal aryl ring; as well as the nature and length of the flexible tether between the rings. The compound showing the best antimalarial activity (cycloguanil-resistant FCR-3 Plasmodium falciparum IC50 = 0.99 mu M) was N-6-(3-(4-chlorophenoxy)propyl)-2-(furan-2-yl)-1,2-dihydro-1,3,5-triazine-4,6-diamine hydrochloride. (C) 2011 Elsevier Masson SAS. All rights reserved.
Synthesis and biological evaluation of new non-imidazole H3-receptor antagonists of the 2-aminobenzimidazole series
摘要:
A novel series of non-imidazole H-3-receptor antagonists was developed, by chemical modification of a potent lead H-3-antagonist composed by an imidazole ring connected through an alkyl spacer to a 2-aminobenzimidazole moiety (e.g., 2-[[3-[4(5)-imidazolyl]propyl]amino]benzimidazole), previously reported by our research group. We investigated whether the removal of the imidazole ring could allow retaining high affinity for the H-3-receptor, thanks to the interactions undertaken by the 2-aminobenzimidazole moiety at the binding site. The imidazole ring of the lead was replaced by a basic piperidine or by a lipophilic p-chlorophenoxy substituent, modulating the spacer length from three to eight methylene groups; moreover, the substituents were moved to the 5(6) position of the benzimidazole nucleus. Within both the 2-alkylaminobenzimidazole series and the 5(6)-alkoxy-2-amino-benzimidazole one, the greatest H-3-receptor affinity was obtained for the piperidine-substituted compounds, while the presence of the p-chlorophenoxy group resulted in a drop in affinity. The optimal chain length was different in the two series. Even if the new compounds did not reach the high receptor affinity shown by the imidazole-containing lead compound, it was possible to get good H-3-antagonist potencies with 2-aminobenzimidazoles having a tertiary amino group at appropriate distance. (c) 2005 Elsevier Ltd. All rights reserved.
A novel class of imidazo heterocyclic compounds, pharmaceutical compositions comprising them and use thereof in the treatment and/or prevention of diseases and disorders related to the histamine H3 receptor. More particularly, the compounds are useful for the treatment and/or prevention of diseases and disorders in which an interaction with the histamine H3 receptor is beneficial.