Table 1. GSH reactivity of heterocyclic electrophiles measured at concentrations of 250 μM. Library members having t_1/2(GSH) > 72 h were considered inactive and are shown in Table S1.

ID	Structure	k GSH	t 1/2(GSH) [h]	ID	Structure	k GSH	t 1/2(GSH) [h]
A1		0.0100	69.4	K6		0.1412	4.9
A2		0.0100	69.2	L6		0.4044	1.7
A5		0.6887	1.0	N1		0.1533	4.5
B4		0.0176	41.0	N3		6.0573	0.1
C3		0.0100	69.0	N4		1.4615	0.5
C4		0.8837	0.8	N5		0.0153	45.2
C5		2.4150	0.3	N6		0.0127	54.6
C6		0.2900	2.4	O4		0.693	1.0
D4		0.3138	2.2	P6		0.1284	5.4
D6		0.0151	46.8	Q2		0.011	63.0
E4		0.0147	47.1	Q5		0.0156	44.5
G4		0.0314	22.5	Q6		0.0130	53.1
G5		0.0414	16.9	R3		0.7872	0.9
H3		0.116	6.0	R4		0.0868	8.0
H4		0.0132	52.3	R5		0.2583	2.7
I6		0.0144	48.0