Condensation of phenol with methyl pyruvate

Methyl pyruvate reacts with phenol, in the presence of hydrogen chloride, y ielding 3-(4-hydroxyphenyl)-3-methyl-2-coumaranone (1a), methyl 2,2-bis-(4- hydroxyphenyl)-propionate (2a) and methyl 2-(4-hydroxyphenyl)-2-(2-hydroxyp henyl)(3a). The structure of 1a was determined by the X-ray diffraction met hod and that of 2a was based on the spectral data. The latter compound was not isolated, its structure (3a) was assigned basing on the GCMS analyses a nd analogy with the compounds 1a and 2a. The crystal and molecular structur e of racemic 3-(4-acetoxyphenyl)-3-methyl-2-coumaranone (1b) was determined at room temperature. The triclinic unit cell contains a couple of enantiom eric molecules connected by weak C-H . . . .O hydrogen bonds.