| Abstract: | (Hydroxyphenyl)ethanones from Dehydroacetic Acid Dehydroacetic acid ( 4 ) reacts with N,N-dimethylformamide dimethylacetal to yield 4-hydroxy-6-methyl-3-3-(dimethylamino)acryloyl]-2H-pyran-2-one ( 5 ). Unsuccessful attempts to produce the pyranopyrandiones 1 and 2 or the 2-(dimethylamino)vinyl]-6-methyl-4-pyrone ( 3 ) by heating 5 with dilute sulfuric acid are reported. The reaction yields 1-(2,4-dihydroxyphenyl)ethan-1-one ( 9 ). Similarly 1-(2-methylamino-4-hydroxyphenyl)ethan-1-one ( 8 ) was obtained from the enamine 7 , and the pyran-2,4-dione 12 from the coumarin derivative 10 . |
