Prepd from o-toluidine by diazotization in HCl soln and treatment of the diazonium chloride with potassium cuprocyanide: Herb, Ann. 258, 9 (1890); Clarke, Read, Org. Synth. coll. vol. I (2nd ed., 1941) p 514. Absorption spectrum: Baly, Ewbank, J. Chem. Soc. 87, 1357 (1905); Purvis, ibid. 107, 503 (1915).