This investigation was undertaken (1) to ob-manner, giving the dihydroxy compound, followed by dehydration of the latter. 5 There are, however, no data available to decide whether ring closure or hydrogenation of the benzene ring is tain further information concerning the mecha-a nism of the formation of hexahydrochroman2 by the hydrogenation of coumarin over Raney nickel, and (2) to investigate the preparation of chromans by the ...
![3,4-dihydro-2H-benzo[h]chromene结构式](https://image.chemsrc.com/caspic/399/3722-87-0.png)