2-Нитробензальдегид

Химические свойства

yellow or bright yellow needle-like crystals. It can volatilize with water vapor and has the fragrance of benzaldehyde. Soluble in ethanol, ether, benzene, slightly soluble in water, flash point>110℃, reacts violently with pyrrole.

Использование

2-Nitrobenzaldehyde is a benzaldhyde with a nitro group substituted in the ortho position. 2-Nitrobenzaldehyde is used in the preparation of dyes and colorants such as Indigo carmine. 2-Nitrobenzaldehyde gas been shown to be a useful photoremovable protecting group as well as in the preparation of more effective ones such as o-Nitrophenylethylene glycol.

Определение

ChEBI: 2-nitrobenzaldehyde is benzaldehyde substituted at the ortho-position with a nitro group. It is a C-nitro compound and a member of benzaldehydes.

Подготовка

2-Nitrobenzaldehyde is synthesized from 2-Nitrotoluene by nitration and oxidation.
Synthesis of 2-Nitrobenzaldehyde from 2-Nitrotoluene

Общее описание

The 2-Nitrobenzyl group of 2-nitrobenzaldehyde is photolabile that can be cleaved when exposed to UV-light.

Синтез

50 g (0.24 mol) of 2-nitrophenylpyruvic acid of melting point 115° C are introduced into 500 ml of aqueous sodium carbonate until a clear solution is obtained. After the addition of 350 ml of toluene, the mixture is cooled to 0° C, and 40 g of solid potassium permanganate is then added in portions at 0°- 3° C. After one hour at 0°- 3° C, 95 ml of 50% strength sulphuric acid are added dropwise. The temperature is not allowed to rise above 30° C. The reaction mixture is filtered, and the toluene phase is separated from the filtrate. The filter residue is washed with toluene, and the combined toluene phases are extracted with 15% strength sodium carbonate solution and with water. The toluene phase is then dried with sodium sulfate and concentrated in a vacuo. The remaining residue consists of 19.7 g (54.7% of theory) of 2-nitrobenzaldehyde, which crystallizes on cooling.

Методы очистки

Crystallise the aldehyde from toluene (2-2.5mL/g) by addition of 7mL pet ether (b 40-60o) for 1mL of solution. It can also be distilled under reduced pressures. [Beilstein 7 IV 584.]