Yield:89331-94-2 94.6%

Reaction Conditions:

with sulfuric acid in dichloromethane;water at 35 - 40; for 4.5 h;Temperature;Solvent;

Steps:

1.1; 1.2 Example 1 A method of preparing a black fluoran thermally sensitable dye in one step, followed by the following steps:
1). To a 500 mL four-necked flask was added 150 mL of dichloromethane,2-carboxy-4'-dibutylamino-2'-hydroxyBenzophenone55.4 g (0.15 mol) and2-methyl-4-methoxydiphenylamine32 g (0.15 mol),Under stirring, 40 mL (about73.5g) 98% sulfuric acid, to the material all dissolved, the temperature maintained at 35 below. After the dropwise addition, the temperature was raised to 40 ° C and refluxed for 4.5 h.2). After the reaction was continued, stirring was continued, 150 ml of water was slowly added to the four-necked flask, and the dichloromethane was recovered by heat dissipation,The temperature of the reaction solution was controlled at 65-70 ° C to recover dichloromethane and incubated for 30 min. Add toluene 150mL, continue to heat up toAfter stirring at 85-90 ° C for 30 min, the mixture was stirred, allowed to stand, and the lower acidic aqueous solution was separated. The upper organic phase was added with a small amount of hot waterThe water is about 60 ° C, about 50 g), the organic phase is cooled to below 20 ° C to crystallize, filtered, and the filter cake is treated with a small amount (about 30 ml)Washed with methanol and dried at 70 ° C for 2 h to give 75.5 g of a white solid in 94.6% yield. By HPLC, the product of formula IVCompound content> 99.5%, melting point 182.6-184.0 ° C.In the benzophenone derivative described in this embodiment, R1 and R2 each represent a butyl group. That is, the benzophenone derivative is2-carboxy-4'-dibutylamino-2'-hydroxybenzophenone;Black fulleane thermal pressure sensitive dye is3-dibutylamino-6-methyl-7-phenylaminofluoran.

References:

Hongsheng Chemical Industry Co., Ltd.;Kong, Ming;Gong, Han;Liu, Yufeng;Tao, Jianguo;Peng, Wenbo;Wan, Degui CN105838105, 2016, A Location in patent:Paragraph 0059-0078

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