Beitrag zur Deutung der Lichtechtheit bei den Chinophtalon‐Farbstoffen

Abstract

1. Mit Hilfe von IR.‐ und NMR.‐spektroskopischen Untersuchungen wird das Vorliegen von intramolekularen Wasserstoffbrücken bei 3′‐Hydroxychinophtalon wahrscheinlich gemacht. Die bei 3′‐Hydroxychinophtalonfarbstoffen stets gefundene hohe Lichtechtheit scheint demnach durch die H‐Brücke zwischen dem OH in 3′‐Stellung und dem CO des Anhydrid‐Fünfrings bedingt zu sein. 2. Umsetzungen von Pyromellitsäure‐dianhydrid (V) mit Chinaldin bzw. 3‐Hydroxychinaldin lieferte eine Anzahl neuerer Chinophtalon‐Abkömmlinge. Die beiden hydroxyhaltigen «Dichinophtalon»‐Pigmente XXII & XXIII zeigten in Weich‐PVC gute Licht‐ und Migrierechtheit.

Solution Structures of Pyrophthalones, I Structure and Conformation of 1,3-Indandionato-2(2-pyridinium)-betaïn — a 1H/13C NMR Approach

“…The proton is situated at the nitrogen, which has been also derived recently from 15 N NMR results [22], and the dipolar resonance form is dominating in the ground state.…”

“…The same problem exists for the dye-stuff quinophthalone (QPH) [14,15], which is included for comparison. Although charge separation and protonation of the nitrogen has been mentioned sometimes [3,5,6,11,12,14,15], many papers stated a planar structure and inferred its stabilization by hydrogen bonding between O and N.…”

Silica gel Catalyzed Synthesis of Quinophthalone Pigments Under Solvent-Free Conditions Using Microwave Irradiation

“…The 13 C-NMR data was also consistent with the proposed structures in all cases. In the IR spectra the C=O/C=C groups were observed around 1635-1670 cm -1 [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ].…”

“…Quinophthalones have achieved great significance in organic synthesis [ 1 , 2 , 3 , 4 ]. Many studies have shown these compounds to be rich sources of innovative chemistry as a number of pharmaceutical products and dyestuffs contain this ring system [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Their ability to act as ligands that form stable complexes with different cations is also well known [ 12 ].…”

Highly efficient one-step microwave-assisted synthesis of structurally diverse bis-substituted α-amino acid derived diimides

“…Here, we describe a one-step process for microwave assisted synthesis of symmetrical a-amino acid derived diimides based on three structurally distinct aromatic cores namely, pyromellitic dianhydride (PMA), 20 biphenyl-tetracarboxylic acid dianhydride (BPDA) 21 and benzophenone-tetracarboxylic acid dianhydride (BTDA) 22 (Scheme 1). We chose these anhydrides due to their potential to deliver diimides with properties different to those of NDIs and PBIs.…”