Table 4.

Chemical shift of C₄ and C₁₁ at different substituents on benzene ring.

Substituent groups			δC (C4 and C11)
R1,6	R2,5	R3,4
OMe	OMe	OMe	106.9–111.9
OH	OMe	OMe	109.9–110.2
OMe	OMe	OH	105.9–107.7
OCH2O		OMe	101.1–103.1