Scheme 1:
General method for the synthesis of 10a–i. Reagents and conditions: (a) NaOH (aq),140 °C, 2h; (b) 30% H
2
O
2
, AcOH, rt, 3h; (c) fuming HNO
3
, 90 °C, 4h; (d) diol, THF, 30% NaOH, rt, 4–8h; (e) anhydrides, pyridine, rt, 6-12h.
