TABLE 1.

MS data for 3-chloropicolinic acid (compound III [Fig. 1]) and 3-chloro-2-methoxymuconic semialdehyde methyl ester (compound II [Fig. 1])^a

Compound	Ionization method	m/z	Relative intensity	Assignment
III	Chemical ionization	158/160	100/32	[MH]+
		140/142	72/24	[MH − H2O]+
		124	24
	EI	157/159	4.7/1.6	M+·
		113/115	100/33	M+· − CO2
		78	50	M+· − CO2, C1·
II	Chemical ionization	205/207	17.4/5.8	[MH]+
		173/175	100/34	[MH − HOCH3]+
		145/147	43/14	[MH − CH3OH, CO]+
	EI	204/206	8.5/2.7	M+·
		175/177	10.7/3.4	M+· − CHO·
		145/147	100/32	M+· − CH3·, CO2

^aThe picolinic acid and the muconic semialdehyde derivative were prepared as described in Materials and Methods.