2-(2,2-Dimethyl-5-oxo-[1,3]-dioxolan-4-ylidene)-n-methyl-n-(4-trifluoromethylbenzyl)-acetamide   、                                                                                      
Paraformaldehyde methylamine   、                                                                                         、                                                                                      
甲醇                                                                                                                                                                                                                                                                                                          以gave 0.31 g (64% yield) of the title compound as white crystals的产率得到4-Hydroxy-1-methyl-5-oxo-2,5-dihydro-1h-pyrrole-3-carboxylic acid methyl-(4-trifluoromethyl-benzyl)-amide