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, M. A.
NEW YORK CITY
1922

ACKNOWLEDGMENT AND DEDICATION

The following research was undertaken at the suggestion of Professor Marston Taylor Bogert to whose interest and advice this work owes whatever merit it may possess.

Y. G. CHEN.

CONTENTS

ABSTRACT OF THE DISSERTATION

1. What was attempted?

Attempt was made to study organic selenium compounds of the heterocyclic series in reference to those properties leading to tinctorial and pharmaceutical possibilities.

2. What were the methods of attack?

(a) Organic selenium compounds were reviewed and their properties examined critically with those of allied compounds.

(b) Some new heterocyclic compounds of selenium were studied and their characteristic properties more closely examined along the desired line.

3. In how far were the attempts successful?

The literature was reviewed and classified with reference to the properties under consideration, and new selenium organic compounds were prepared and studied which it is hoped may throw some additional light upon the problem.

4. What contribution actually new to the science of chemistry has been made?

(a) Compounds newly made have been shown to exhibit a distinct tinctorial value in comparison with their analogues.

(b) They have been shown to be chemically easier to handle than the corresponding sulphur compounds.

(c) Selenium, in the nucleus of cyclic compounds, has been shown to be instrumental for a positive coloration at least equal to the —NH— or —S— groupings. The selenocarbonyl, :C:Se, has been shown to be a more powerful chromophore than thiocarbonyl, :C:S, or carbonyl itself, :C:O.

(d) Two series of azo dyes of selenium have been prepared and have been shown to possess a marked tinctorial value.

(e) The following new compounds have been prepared:

• 2-methyl-4-selenoquinazolone
• 2-phenylbenzoselenazole[A]
• 6-nitro-2-phenylbenzoselenazole
• 6-amino-2-phenylbenzoselenazole