Five-membered 2,3-dioxoheterocycles: LXIV. Reactions of 1-methyl-3,4-dihydroisoquinolines with 5-arylfuran-2,3-diones and (Z)-alkyl 4-aryl-2-hydroxy-4-oxobut-2-enoates. Crystal and molecular structure of (2Z,5Z)-3-hydroxy-5-{8,8-dimethyl-2,3,8,9-tetrahydro[1,4]dioxino[2,3-g]isoquinolin-6(7H)-ylidene}-1-phenylpent-2-ene-1,4-dione

5-Arylfuran-2,3-diones and (Z)-alkyl 4-aryl-2-hydroxy-4-oxobut-2-enoates react with 3,3-dialkyl-1-methyl-3,4-dihydroisoquinolines to give (2Z,5Z)-1-aryl-3-hydroxy-5-[3,3-dialkyl-3,4-dihydroisoquinolin-1(2H)-ylidene]pent-2-ene-1,4-diones whose structure has been proved by XRD analysis.