P-XYLOQUINONE

Chemical Properties

yellow to brown crystalline powder

Uses

2,5-Dimethyl-1,4-benzoquinone may be used in a key step involved in the total synthesis of ()-cyathin A₃.

Synthesis Reference(s)

Synthetic Communications, 25, p. 1669, 1995 DOI: 10.1080/00397919508015851
The Journal of Organic Chemistry, 53, p. 5453, 1988 DOI: 10.1021/jo00258a010

General Description

2,5-Dimethyl-1,4-benzoquinone is a quinone derivative. Its reaction with jack bean urease in phosphate buffer, pH 7.8 has been studied. It is present as one of the component of defensive secretion of opilionid Acanthopachylus aculeatus. It has been investigated as inhibitor of jack bean urease in 50mM phosphate buffer, pH 7.0.

Synthesis

2,5-Dimethyl-p-benzoquinone was prepared as follows:
Method 1: 80 g of 2,5-dimethylphenol was added to 300 mL. Dimethylformamide in 500 ml. The resin kettle oxidizer is provided with an air inlet, stirrer, thermometer and reflux condenser. 2.5 g of saladine catalyst is added and the contents are heated to a temperature of 35C. Air was then introduced at a rate of 0.30 l/min. The stirrer was run at 277 rpm. When the oxidation unit reached a pressure of 150 psi, venting was initiated to control the pressure. Oxidation was continued until 2,6-dimethylphenol was no longer present. The 2,5-dimethyl-p-benzoquinone product was isolated with good purity by quenching the reaction solution with cold water, filtering and drying. A yield of 99% dimethylquinone was obtained.
Method 2: 0.1 mmol of 2,5-dimethylphenol was mixed with trifluorotoluene, solid catalyst onion carbon, and oxidizing agent tert-butyl hydrogen peroxide by adding them to a closed glass vessel, and then ultrasonicated to form a suspension (for 5 min). Wherein, 5 ml of trifluorotoluene, the molar ratio of onion carbon to 2,3,6-trimethyl-p-phenol was 6.66: 1. The molar ratio of oxidizer to 2,3,6-trimethyl-p-phenol was 3.6: 1. The mixed suspension was placed in an oil bath and heated to 80C under stirring conditions. After 12 hours of reaction, the reaction vessel was removed from the oil bath, cooled to room temperature, and the liquid-solid mixture was poured out, which was filtered to obtain the solid catalyst and the remaining liquid-phase mixture, and the 2,5-dimethyl-p-benzoquinone product was isolated.

Purification Methods

Crystallise the quinone from EtOH. [Beilstein 7 IV 2090.]