3-Hydroxy imidazole 1-oxides preparation

The N-hydroxy structure (26) was preferred123 to an iV-oxide representation on account of the amphoteric nature of the product and because the derived acetate formed a well-defined hydrochloride salt. Hydrogenation of these N-hydroxyimidazoles over Raney nickel gives imidazoles in 60-94% yields.122 The reaction has been adapted for the preparation of 4-mercaptoimidazoles, using an a-ketothionamide (27) with an aldimine.124... 

When l-hydroxy-3-imidazoline 3-oxides (263) are treated with HCl they dehydrate forming imidazole 3-oxides (Scheme 153) (73CHE1175). Reduction of 4//-imidazole N-oxides with borohydride leads to either 1-hydroxy-imidazolines or -imidazolidines, depending on the position of the oxide function. Under the same conditions 4//-imidazole 1,3-dioxides give 1,3-dihydroxyimidazolidines (76CHE1280). The 4iT-imidazole AT-oxides are prepared by heating 5,5-disubstituted l-acyloxy-3-imidazoline 3-oxides in vacuo. 

Novel fluorescent ATP analogues where the two tertiary carbons of the etheno-moiety of A A -etheno adenosine have been modified by the introduction of a /7-nitro or a / -amino-phenyl group and a hydroxy moiety (100) have been prepared via a Kornblum oxidation reaction and imidazole formation. These compounds exhibited relative stability towards type II ATPDase. ... 

N-Substituted 3)5-acetoxy-6/ -amino-5a-androstanes bearing histidine and related imidazole and triazole derivatives have been prepared. Allylic oxidation with selenium dioxide of 3a- and 3)8-dimethylamino-5-enes, c.g. (498) and similar steroids, gave 4/ -hydroxy-5-ene and the allylic rearrangement product... 

Several copper-catalyzed 7 -arylation reactions of imidazole have been published. The coupling of arylboronic acids with imidazole in the presence of binuclear bis-p,-hydroxy copper (11) complexes in air has been carried out at ambient temperature without the need for base <04TL7659>. A variety of A -arylimidazoles were prepared in excellent yields through the cross-coupling of arylboronic acids with imidazole in methanol or water with copper(I) chloride <04CC188>. Copper(II) oxide-coated nanoparticles were used catalytically in the Ullmann coupling of imidazole with various aryl chlorides with cesium carbonate in dimethyl sulfoxide <04CC778>. 

---