21,23-dithia-3,13-diazaporphycenes - Novel aromatic porphycene analogues incorporating thiazole

The syntheses of the first examples of aromatic thiazole-containing porphyc ene analogues 3 have been accomplished by oxidation of the corresponding 3, 20:10,13-diepithio-6,9:16,19-diimino-1,11-diaza[20]annulenes 9 with DDQ. Co mpounds 9a-c have been synthesized by McMurry coupling reaction of the difo rmylated 2-(1H-pyrrol-2-yl)thiazoles 8a-c, readily available by a three-ste p reaction sequence using 2-pyrrolethiocarboxamide (4) as starting material . The aromaticity of the 21,23-dithia-3,13-diazaporphycenes 3 is clearly es tablished by NMR and UV/Vis spectroscopy and verified by X-ray crystal stru cture analysis of 3b.