Na2B4O7 in methanol

1: AcCl / CH2Cl2 2: Na2B4O7 / methanol View Scheme

pyridine; Collins oxidation agent; oxygen 1.) 45 deg C, 60 h; 70 deg C, 5 h, 2.) room temperature, 30 min; Yield given. Multistep reaction. Yields of byproduct given. Title compound not separated from byproducts;