TY - JOUR AU - Adam, Jean-Marie AU - Sutter, Peter AU - Winkler, Tammo PY - 1994/11/30 Y2 - 2024/03/28 TI - Malononitrile, a Synthetic Tool for New Chromophoric Systems JF - CHIMIA JA - Chimia VL - 48 IS - 11 SE - Scientific Articles DO - 10.2533/chimia.1994.505 UR - https://www.chimia.ch/chimia/article/view/1994_505 SP - 505 AB - <p>New near-IR-absorbing dyes were synthesized by condensation of the dicyanovinyl derivative of 1-acetyl-3-oxo-2,3-dihydroindole with nitroso compounds. The resulting products were found to be mixtures (ca. 9:1) of the <em>(</em>E)- and (<em>Z</em>)-isomers. The more bathochromic (<em>E</em>)-form could be converted into the (<em>Z</em>)-form by heating in methanol. At higher temperature new cyclization products were obtained. A mechanism of the isomerisation and cyclization is proposed.</p> ER -