| 摘要 |
<p>A chemical method for splitting the pyran ring of compounds such as 2,6,6-trimethyl-5,6-dihydro-4H--pyran is disclosed which consists in reacting the 4H-pyran derivatives concerned with water and a halogen-containing or hologen-donating catalyst at a comparatively low temperature, i.e. from 50.degree.C to 130.degree.C. Interesting results are obtained and a selection field is afforded as regards the products of the pyran-ring cleavage.</p> |
