Synthesis of 2-methyl-4-selenoquinazolone, 2-phenylbenzoselenazole, and its derivatives / Dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Faculty of Pure Science of Columbia University

by Yü-Gwan Chen

Thiophene, colorless
liquid

Pyrrol, colorless liq.
but turns brownish in air

Selenophene, yellow liq.
after repeated extraction[B]

This brings selenophene more akin to pyrrole than thiophene, but the group -NH- in the molecule of pyrrole is an auxochrome. The selenium atom in a cyclic compound also acts like an auxochrome.

Selenoantipyrine[(37)],

forms pure yellow crystals from alcohol, while the corresponding compounds of oxygen and sulphur are colorless.

Similarly, the 2-methyl-4-selenoquinazolone is deep brown in color, while the thio compound, prepared by Bogert and Hand[(38)] is light brown or yellow and the corresponding oxygen compound is colorless or nearly so.