I gave some old POCl3 a shot
42,8g TMB is disolved in 300mL DMF, cooled in a icebath, and then 25mL 10years ol POCl3 is added over 60min. The reacton is left for 2H, poured out in 1,6L wather, and the nex day the TMBA is filtered off.
Yeald 43,8g(88%) og nice pink aldehyde.