Synthesis, Reactions, and Structure of 5-Cyano-4-ethoxy-1-ethoxycarbonyl-2-methylazuleno[1,8-b,c]pyran
作者:Chi-Phi Wu、Ling-Yu Cheng、Yuh-Sheng Wen、Chwan-Deng Hsiao
DOI:10.1002/jccs.199700041
日期:1997.6
AbstractBicyclic azulene compounds, ethyl 4‐(cyanoethoxycarbonylmethyl)‐2‐methylazulene‐1‐carboxylate (2) and ethyl 4‐(cyanoethoxycarbonylmethyl)azulene‐1‐carboxylate (3) were prepared from ethyl 4‐chloro‐2‐methylazulene‐1‐carboxylate (7) and ethyl 4‐ethoxyazulene‐1‐carboxylate (8), respectively. Oxidation of 2 with DDQ gave the title compound, 5‐cyano‐4‐ethoxy‐1‐ethoxycarbonyl‐2‐methylazuleno[1,8‐b,c]pyran (1) and a minor compound, ethyl 4‐cyanomethyl‐2‐methylazulene‐1‐carboxylate (9). Oxidation of 3 by DDQ produced only ethyl 4‐cyanomethylazulene‐1‐carboxylate (10), Reaction of 1 with 100% H3PO4 at room temperature and 100 °C gave 5‐cyano‐4‐ethoxy‐2‐methylazuleno[1,8‐b,c]pyran (11) and 2‐methyl‐4,5‐dihydrozuleno[1,8‐b,c]pyran‐4‐one (12), respectively. All the new compounds were characterized by IR, UV‐vis, NMR and Mass spectra, and the structure of 1 was determined by X‐ray crystallography. Crystal data for 1; space group P21/n, a = 7.391(1), b = 9.660(5), c = 22.859(1) Å, B = 97.01(1)°, V = 1620.0(3) Å3, Z = 4, with final residuals R = 0.047 and Rw = 0.055.