1: 1.) H2O, AcOH; 2.) N,N-dimethylolpyridine / 1.) methanol, toluene, r.t., 1 h; 2) ether, 1 h 2: 80 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / 5 °C 3: 90 percent / aq.NaOH / methanol / 2.5 h / 5 - 25 °C View Scheme