Table 2. In vitro enzymatic kinase assays and anti-proliferative activity of ethynyl-linked isoquinazolines.

Compound	% inhibition				IC50 (nM)
	EGFR		HER2		SKBR3	A431
	1 μM	0.1 μM	1 μM	0.1 μM
13a	95	71	95	68	90	850
13b	82	36	88	30	414	N.Da
13c	88	49	93	48	567	N.D
13d	94	73	98	72	125	N.D
13e	74	29	88	28	427	N.D
13f	98	89	96	81	12	414
Lapatinib	99	94	96	70	23	418

^aN.D: not determined.