Summary Tetrazotieed diaminodiphenyls, when treated with arsenious oxide in sodium carbonate solution, are in part converted into cyclic azo compounds. ... EDMONTON, ALBERTA, CANADA RECEIVED JUNE 2, 1936 (4) Ullmann and Dieterle, Be., 87,24 (1904). ... [CONTRIBUTION FROM THE DEPARTMBNT OF BIOLOGICAL CHEMISTRY, COLUMBIA UNIVERSITY] C arb oxym e t hox ylamin e ... BY E. BOREK~ AND H. T. CLARKE ... In the course of experiments on ...