We report on the reactions of diazenes 1 and 2 with 1,3-dicarbonyl compounds. The first step involves a regioselective attack of the diazene on the active methylene group, giving the Michael adducts 3 or 4, and can be performed either in the presence of sodium acetate or DBN (1,5-diazabicyclo[4.3.0]non-5-ene). The Michael adducts underwent ring-closure leading to 2-imidazolidinones 5 or 6 which were isolated in some cases. We found that 5 or 6 easily eliminated water in the presence of an acid to give imidazolin-2-ones 7 or 8 as the final products. The rate-determining step of this last mentioned process depends on the stereochemistry at C4 and C5 of the initial 2-imidazolidinone. A one-pot procedure to produce 7 or 8 directly from the diazene and the appropriate dicarbonyl partner is also described.
Diazenedicarboxamides as inhibitors of d-alanine-d-alanine ligase (Ddl)
作者:Andreja Kovač、Vita Majce、Roman Lenaršič、Sergeja Bombek、Julieanne M. Bostock、Ian Chopra、Slovenko Polanc、Stanislav Gobec
DOI:10.1016/j.bmcl.2007.01.015
日期:2007.4
D-Alanine-D-alanine ligase (Ddl) catalyzes the biosynthesis of an essential bacterial peptidoglycan precursor D-alanyl-D-alanine and it represents an important target for development of new antibacterial drugs. A series of semicarbazides, aminocarbonyldiazenecarboxylates, diazenedicarboxamides, and hydrazinedicarboxamides was synthesized and screened for inhibition of DdlB from Escherichia coli. Compounds with good inhibitory activity were identified, enabling us to deduce initial structure-activity relationships. Thirteen diazenedicarboxamides were better inhibitors than D-cycloserine and some of them also possess antibacterial activity, which makes them a promising starting point for further development. (c) 2007 Elsevier Ltd. All rights reserved.