Dinitrile quinoxaline-2,3-dicarboxylic acid

At first the unsubstituted metal-free quinoxalinoporphinazine 129 was obtained in a 67% yield by heating dinitrile quinoxaline-2,3-dicarboxylic acid in benzyl alcohol and chlorobenzene at 180°C with metallic lithium followed by the treatment of the resulting complex with dilute hydrochloric acid (1969ZOB2536).A higher yield of 129 (Ri = = R4 = H,... [Pg.80]

X = HH) (95%) is achieved when carried out in fusion with sodium hydroxide at 220 °C within 15 min (2006RUP2269530). Under the same condition the tert-butyl analogue 129 (R =R = R = H, R = f-Bu, X = HH) has been obtained from corresponding dinitrile quinoxaline-2,3-dicarboxylic acid 65j in a 75% yield (2008ZOB1214). Metal-free benzol ] quinoxalinoporphinazine 129 (R = R = H, R = R = Z1,... [Pg.81]

Treatment of quinoxaline-2,3-dicarboxylic acid anhydrides, diesters, or dinitriles with hydrazine monohydrate gives pyridazino[4,5-h]quin-oxalines (Scheme 7). ... [Pg.152]

Quinoxaline-2-carboxylic acid with thionyl chloride gives the acid chloride (79%), which undergoes the expected reactions.166 The gas-phase pyrolysis of quinoxaline-2,3-dicarboxylic anhydride (157) over a Nichrome coil gives o-phthalonitrile (158) (72%), probably via 2,3-quinoxalyne (159) which ring-cleaves, and the diisocyanide subsequently rearranges thermally to the dinitrile.167... [Pg.404]

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