Scheme 3. Synthetic Route to 10a–i and 11a–i Derivatives.

Reagents and conditions: (i) acetone, NaOH 1 N, 80 °C, 5 h, 41–63% yield; (ii) TosMIC, NaH, 2:1 Et₂O dry/DMSO dry, N₂, room temp, 1 h, 87–100% yield; (iii) proper arylalkyl halide, DMF, K₂CO₃, 80 °C, 2–24 h, 15–59% yield; (iv) diethyl oxalate, EtONa, THF dry, N₂, room temp, 2 h, 55–100% yield; (v) MeOH, NH₂NH₂ dihydrochloride, Et₃N, CH₃COOH gl, room temp, 2 h, 20–65% yield; (vi) THF, NaOH 20%, 90 °C, 12 h, 62–100% yield.