Table 2. Condition Screening and Optimization of Selective Mono-ester Hydrolysis Reaction of Pyridinone 3 in Continuous Flow^a.

experiment name	3/baseb	base	temperature (°C)	time (min)	% yieldc
1	1/6	LiOH	50	5	5
2	1/6	LiOH	75	5	14
3	1/6	LiOH	100	5	100
4	1/4	LiOH	100	15	100
5	1/3	LiOH	100	20	100
6	1/3	KOH	100	20	100
7	1/3	NaOH	100	20	84
8	1/3	TBAOH	100	20	41
9d	1/3	KOH	100	1	98–100
10e	1/3	KOH	100	1	98–100

^aStandard conditions: feed one—pyridinone (0.1 M, 1 equiv), feed two—base, and using methanol as a solvent in both feeds.

^bMolar equivalence.

^cCarboxylic acid 4 percentage yield determined by HPLC using a synthetic standard.

^dCosolvent mixture (2:9 ratio; MeOH: H₂O (V/V)).

^eCosolvent mixture (10:1 ratio; MeOH: H₂O (V/V)).