Zur Chemie der Ketene / Chemistry of Ketenes

Abstract

Phenylmalonylchloride reacts with sodium acetate in boiling benzene if possible via a dimeric phenylketenecarboxylic acid to give 4-acetoxy-3,6,7-triphenyl-3,6-cycloheptadiene-1,2,5-trion. The structure of this compound is deduced by mass spectrometry. Analogous compounds are obtained with the sodium salts of other carboxylic acids. A reaction mechanism is proposed.

Tris(arylmethyl) Derivatives of 1,3,5-Trimethoxy- and 1,3,5-Triethylbenzene

“…Compound 6 (200 mg 0.41 mmol) was dissolved in 20 mL of dry CH 2 Cl 2 , and to the solution was added 0.38 mL (4.9 mmol) of trifluoroacetic acid followed by 1.56 mL of triethylsilane (9.8 mmol), and the mixture was stirred at rt for 70 h. After neutralization with a saturated solution of NaHCO 3 , the phases were separated and the organic phase was dried (MgSO 4 ) and evaporated. The residue was recrystallized from CHCl 3 /ether to yield 146 mg (81%) 7 : mp 115 °C (lit . mp 101 °C); 1 H NMR (400 MHz, CDCl 3 , rt) δ 7.35 (d, J = 7.0 Hz, 6H), 7.18 (t, J = 7.2 Hz, 6H), 7.06 (t, J = 7.2 Hz, 3H), 4.15 (s, 6H), 3.27 (s, 9H); 13 C NMR (100 MHz, CDCl 3 , rt) δ 157.8, 142.0, 128.61, 128.57, 126.1, 124.4, 62.0, 30.8; CI MS m / z 439.2 (MH + ).…”

“…If properly oriented, the four aromatic rings could provide four “walls” delimiting a hydrophobic pocket . The hexasubstituted benzene 7 has been prepared by Wittmann and co-workers via trimerization of the ketene derived from benzylmalonyl dichloride, followed by treatment of the resulting product with dimethyl sulfate/methanolic KOH . In this paper, we describe an alternative synthesis of 7 and the preparation and crystal structure of a hexasubstituted benzene structurally related to 1 in which three ethyls have been replaced by arylmethyl groups ( 9b ).…”