4,4-dimethoxybut-3-en-2-one

4-methoxybenzocyclobutenone

4-methoxybicyclo[4.2.0]octa-1(6),2,4-trien-7-one

1-(3,3-dimethoxy-2-phenylcyclobutyl)ethanone

2-chloro-6,8-dimethoxynaphthalene-1,4-dione