277330-95-7Relevant academic research and scientific papers
Base-promoted isomerization of cis-4-formyl-2-azetidinones: Chemoselective C4-epimerization vs rearrangement to cyclic enaminones
Alcaide, Benito,Aly, Moustafa F.,Rodriguez, Carolina,Rodriguez-Vicente, Alberto
, p. 3453 - 3459 (2007/10/03)
Two simple, efficient, and complementary methods for the regiospecific C4-epimerization of cis-4-formyl-2-azetidinones 1-3 are described. The first method uses 40% aqueous dimethylamine as reagent in heterogeneous medium with benzene at room temperature, in the presence of benzyltributylammonium bromide (3-4 mol %) as the phase-transfer catalyst. This transformation tolerates alkyl, alkenyl, alkynyl, aryl, and alkoxy substituents at the C3 of the 2-azetidinone ring. However, limitations of this isomerization are as follows: (i) only N-(p-methoxyphenyl)-β-lactams can be used, and (ii) transformation is less compatible with heteroatomic substituents bonded to the C3 position of the 2-azetidinone ring. A highly general solution to these problems relies on the use of sodium carbonate as the isomerization reagent in different solvents. We also describe a novel base-promoted rearrangement of the β-lactam ring to cyclic enaminones 6 and 21, involving an E1cB-elimination reaction in cis-4-formyl-2-azetidinones.
Studies on Lactams. 81. Enantiospecific Synthesis and Absolute Configuration of Substituted β-Lactams from D-Glyceraldehyde Acetonide
Wagle, Dilip R.,Garai, Chandra,Chiang, Julian,Monteleone, Michael G.,Kurys, Barbara E.,et al.
, p. 4227 - 4236 (2007/10/02)
Optically active 3,4-disubstituted 2-azetidinones have been prepared in good yield by the annelation of Schiff bases from D-glyceraldehyde acetonide with acid chlorides (or equivalent) and triethylamine.The utility of this enantiospecific synthesis was ex
