Preparation of Pyrimidine-N-oxides by Condensation of Functionalized Enamides with Hydroxylamine Hydrochloride
作者:Hans-Ulrich Reissig、Reinhold Zimmer、Tilman Lechel、Giaime Rancan、Mrinal Bera
DOI:10.1055/s-0030-1258088
日期:2010.7
β-Alkoxy-β-ketoenamides and hydroxylamine hydrochloride smoothly provide pyrimidine-N-oxides under very mild conditions. Alkyl, aryl, and heteroaryl substituents are compatible with this new method. By treatment with acetic acid anhydride these pyrimidine-N-oxides undergo a rearrangement furnishing highly functionalized 6-acetoxymethyl-substituted pyrimidine derivatives in good yields. Our method,
Three-Component Synthesis of Highly Functionalized 5-Acetyloxazoles
作者:Tilman Lechel、Dieter Lentz、Hans-Ulrich Reissig
DOI:10.1002/chem.200900386
日期:2009.5.25
AbstractBy a flexible three‐component synthesis, alkoxy‐substituted enamides are easily available from lithiated alkoxyallenes, nitriles and carboxylic acids (see scheme). The treatment of these versatile intermediates with trifluoroacetic acid provided 5‐acetyloxazoles in moderate to good yields. Different substituents are possible at C‐2 and C‐5 and the 5‐acetyl group is a suitable handle for further synthetic transformations.magnified image