Über α‐Halogenäther, IV. Synthesen aromatischer Aldehyde mit Dichlormethyl‐alkyläthern

Abstract

Aromatische Kohlenwasserstoffe geben mit Dichlormethyl‐alkyläthern bei Gegenwart von Friedel‐Crafts‐Katalysatoren in guten Ausbeuten die entsprechenden Aldehyde. Zur Darstellung der Chloräther im Labormaßstab wird ein einfaches Verfahren angegeben.

Synthesis of salicylaldehydes from phenols via copper-mediated duff reaction

“…Numerous formylation methods were developed to prepare diverse aromatic aldehydes from corresponding phenols [6], such as the Duff reaction [7][8][9], Vilsmeier-Haack reaction [10][11][12], Reimer-Tiemann reaction [13][14][15], Gattermann-Koch reaction [16,17], Gattermann reaction [18,19], Rieche reaction [20][21][22], and paraformaldehyde/MgCl 2 reaction [23,24]. These methods possess their individual advantages, however, low ortho-selectivity of the most of these methods and poor yields sharply limited their application in industry [25].…”

Porphyrin-o-quinones as Model Systems for Electron Transfer and Catecholase Reactions

“…13 C-NMR spectroscopy is especially suited to the task of checking for the formation of the isomeric p-quinones or the reduced porphyrin catechols during the purification steps. Investigations by Hollenstein and von Philippsborn showed that the carbonyl resonances of o-quinones are the strongest high-field shifted carbonyl reso-nances of six-membered cyclic ketones.…”

“…Both aldehydes were prepared by Rieche formylation [13] from the respective 1,4-dialkyl-2,3-dimethoxybenzenes (Scheme 3). Despite the high steric demand in the veratrol, aldehyde 21 was obtained in 60% yield.…”

“…Analytical thin-layer chromatography (TLC) was carried out using Merck silica gel 60 plates (precoated sheets, 0.2 mm thick, fluorescence indicator F254). Ϫ 1 H-NMR spectra were recorded at frequencies of 500 MHz (Bruker, AMX 500), 13 C-NMR spectra at 126 MHz. All chemical shifts are given in ppm, referenced on the δ scale downfield from the TMS signal.…”

Discotic Liquid Crystals of Transition metal Complexes 23: Synthesis and Mesomorphism of Tetrakis(3,4-di-n-alkylphenyl)porphyrin Derivatives and Their Metal Complexes

“…For the synthesis of 1,2-dialkylbenzene the Grignard reaction was carried out by the method of Tamao et al [16]. For the synthesis of 1,2-dialkylbenzaldehyde the formylation was followed by the method of Riche et al [17]. The synthesis of (C n ) 8 TPPH 2 (2a) was carried out by the method of Adler et al [18].…”