Ultrasonic-Assisted Synthesis of Two t-Butoxycarbonylamino Cephalosporin Intermediates on SiO₂

Table 2

The effect of SiO₂ and ultrasound on the yields of the Boc-ACLE.

Number	SiO2	Ultrasound	Reaction time	Yield%
1	✕	✕	6 h	15
2	✓	✕	6 h	35
3	✕	✓	6 h	40
4	✓	✓	30 min	96

Note: ✕: no; ✓: yes.