HCID 20063315, compound → HCID 20063351, compound

Participants

Reaction Steps

A stirred mixture of a 2:1 mixture of the erythro- and threo-diastereoisomers of (E)-3,5-dihydroxy-7-(2-methyl-1-oxo-4-phenyl-1,2-dihydroisoquinolin-3-yl)hept-6-enoic acid (0.1 g; prepared as described in Example 2) in dry toluene (10 ml) and glacial acetic acid (2 drops) was heated at reflux for 1 hour. Further quantities of toluene (15 ml) and glacial acetic acid (2 drops) were added and the mixture was heated at reflux for a further period of 3.5 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure to half volume. The resulting white solid was filtered off and washed with petroleum ether (b.p. 40°-60° C.), to give (E)-4-hydroxy-6-[2-(2-methyl-1-oxo-4-phenyl-1,2-dihydroisoquinolin-3-yl)ethenyl]-3,4,5,6-tetrahydro-2H-pyran-2-one (0.07 g), m.p. 190°-193° C. [Elemental analysis: C, 71.1; H, 5.52; N, 3.52%; calculated for C23H21NO4 : 0.75 H2O: C, 71.0; H, 5.8; N, 3.6%].

Provenance & Evidence