Table 2. Reaction Condition Experiments for Deprotection of Ketal N-Acyl Hydrazones.

entry	catalyst	solvent	time	conv (%)e	by product (conv. %)e
1	p-TsOHa	acetone:water	40 min	45	38
2	p-TsOHb	acetone:water	40 min	49	35
3	1 M HClc	THF	3 h	—	—
4	Bi(NO3)3·5H2Od	CH2Cl2	2 h	98	—

^aMolar ratio of 4a:catalyst = 1:1.

^bMolar ratio of 4a:catalyst = 1:0.5.

^cMolar ratio of 4a:catalyst = 1:0.01.

^dMolar ratio of 4a:catalyst = 1:0.25.

^eDetermined by GC–MS.