The title compound, C12H13ClO4, was prepared from the Vilsmeier-Haack react
ion on phloroacetophenone. The chlorovinyl and one of the methoxy substitue
nts are twisted through about 75 degrees with respect to the aromatic plane
, whilst the other substituents are almost coplanar with the ring. Intermol
ecular hydrogen bonding involving C-H . . .O interactions generates one-dim
ensional chains in the direction of the a axis.