RH, CHI, CH (CHa), potassium acid sulfate. The resulting indene was hydrogenated catalytically. Treatment of the indans with diazoacetic ester followed by hydrolysis and simultaneous decarboxylation and dehydrogenation gave the desired azulenes. In accordance with the rules formulated by Plattner5 4, 5-dimethylazulene is a blue oil which exhibits a violet tinge in solution. 6 The spectra of 2, 4, 5-trimethylazulene and of 2- ...
