Table 2. Insecticidal activity and residual efficacy of pyrimidine derivatives against BPH.

No.	Z1–Z2	X	LC90 (mg a.i./L)	Residual efficacy (100 mg a.i./L)
2b (lead compound)	none	SiMe3	0.03–0.1	C
10	none	t-Bu	0.1–0.3	D
11	O	t-Bu	0.3–1	D
12	CH2–O	t-Bu	>30	D
13	O–CH2	t-Bu	0.1–0.3	C
14	O–CH2	Cl	1–3	D
15	O–CH2	CF3	0.3	C
Buprofezin	—	—	0.3–1	B*

*: 125 mg a.i./L