Abstract
The rates of hydrolysis reaction of 3, 4-dihydro-2 H-pyran-2-carboxaldehyde and 3, 4-dihydro-2 H-pyran-2-methanol catalysed by hydrogen ion were measured and it was found intrinsically the same as that of n-butyl vinyl ether. This result suggests that the vinyl ether linkage in the dihydro-pyran ring has no singularity because of its existence in the ring structure.
After the hydrolysis reaction, the resulting solutions of the above two pyran-ring compounds were oxidized with some reagents. In the case of potassium permanganate, periodic acid and hydrogen peroxide, the main product was glutaric acid or glutaraldehyde. On the other hand, nitric acid gave oxalic acid and succinic acid. In this case -hydroxyadipic acid and 5, 6-dihydroxyhexanoic acid (or their lactones), respectively, are considered to be intermediates. The mechanism of oxidation with nitric acid is expected to differ from that with general oxidizing reagents.
