2,4,5-Trichloropyrimidine is used in the synthesis of potent and selective anaplastic lymphoma kinase (ALK-5) inhibitors, used as an anti-tumor treatment. Besides, this material is also used in the synthesis of EGFR inhibitors.

Synthesis of 2,4,5-trichloropyrimidine

670 g (6.5 mols) of sulphur dichloride and (as the diluent) 250 ml of disulphur dichloride are initially introduced into a 2 l three-necked flask, which is provided with a stirrer, dropping funnel and thermometer, at 35° C. 87 g (0.5 mol) of molten (2-cyanoethyl)-methyl-dithiocarbamic acid methyl ester are now added dropwise in the temperature range from 35° to 40° C. in the course of half an hour, whilst stirring and occasionally cooling with ice-water. After the addition has ended, stirring is continued at 35°-40° C. for about a further quarter of an hour until the evolution of gas has ended. The reaction mixture is then heated to the reflux (137° C.) in the course of about 2 hours, whilst stirring, whereupon a thick precipitate forms in the temperature range from about 60° C. and redissolves from about 120° C. The formation of the 2,4,5-trichloropyrimidine has ended when a clear solution is present and no further evolution of gas is observed. All the constituents of the reaction mixture which can be distilled up to a bath temperature of 150° C./14 mm Hg are then distilled off. According to analysis by gas chromatography, the distillate contains 78 g (corresponding to 85% of theory) of 2,4,5-trichloropyrimidine. If a stream of chlorine in slight excess (which can be detected from the greenish color of the off-gas) is passed into the distillation residue from 150° C. up to an internal temperature of about 180° C. for 1/2-1 hour and all the constituents which can be distilled are then distilled off under a waterpump vacuum up to a bath temperature of 200° C., according to analysis by gas chromatography a further 4 g (corresponding to about 4% of theory) of 2,4,5-trichloropyrimidine are obtained. By rectification of the product on a Ag-mirrored packed column of 1 m length, 2,4,5-trichloropyrimidine is obtained at boiling point12 94°-96° C. in a purity of over 99%.[1]

Anti-Wrinkle and Dyeing Properties of Silk Fabric

2,4,5-trichloropyrimidine (TLP) is a heterocyclic compound containing nitrogen, which has been successfully applied in various fields due to its pharmacological and strong biological activities. Halogen-pyrimidine reactive dyes are widely used in the printing and dyeing industry. For example, 2,4,5-trichloropyrimidine is often used as an intermediate in medicine and reactive dyes. However, to the best of our knowledge, few studies have been conducted on their use in textile finishing. To prepare silk with good crease resistance, the effects of different TLP dispersants, various alkaline agents and their concentrations, Na2SO4 concentration, finishing product time, and temperature conditions on the anti-crease performance of silk will be investigated to determine the best finishing product process. As shown, when TLP dispersion is in the range of 1–5 g/L, the crease resistance of the finished silk fabric increases gradually with the increasing concentration.[2]

However, when the 2,4,5-trichloropyrimidine concentration exceeds 3 g/L, the crease recovery angle almost does not increase or even decreases slightly. To reduce cost, the concentration of the finishing agent is 3 g/L, which is optimal. An alkaline agent provides an alkaline environment and is one of the most important factors in the final finishing process. Under acidic and neutral conditions, only –OH reaction occurs on silk, whereas, in an alkaline environment, both –NH and –OH of silk are covalently bonded with 2,4,5-trichloropyrimidine. In terms of fabric strength, with the increase in finishing agent TLP concentration, the cross-linking between TLP and silk fabric increases, in order that the macromolecules of silk fabric are not easy to slip, and the breaking strength decreases. It can be seen, when TLP concentration increased to 4 g/L, the fracture strength of silk fabrics decreased by 3.7% compared with unfinished fabrics, and the SD was 0.8, which does not affect the subsequent use performance of silk fabric. Fve tests were carried out on fabrics finished with different concentrations of 2,4,5-trichloropyrimidine. Through the one-way analysis of variance (ANOVA), the F-value is greater than 1, indicating that the concentration of finishing agent is the main factor affecting the change of fabric strength when other conditions are fixed.

In this study, silk fabrics were treated and finished with TLP compounds, and an energy-saving anti-wrinkle finishing process was obtained by impregnation. The optimal finishing process conditions are as follows: 2,4,5-trichloropyrimidine concentration of 3 g/L, NaHCO3 concentration of 6 g/L, Na2SO4 concentration of 8.0 g/L, finishing temperature of 65 °C, and finishing time of 40 min. In addition, TLP can work with dyes to reduce the dyeing and finishing process time. The results showed that the finishing process did not lead to clear damage to the physical and mechanical properties of the silk fabric, and the fold recovery angle of the finished silk fabric was increased by 16–20% compared with the unfinished fabric. Furthermore, the finished silk fabric shows good hand feeling, whiteness, and dyeing properties. 2,4,5-trichloropyrimidine could be a promising formaldehyde-free anti-wrinkle finishing agent for silk.[3]

References

[1]BAYER - US4171442, 1979, A

[2]Abuelela A.M., Mohamed T.A., Wilson L.D., Zoghaib W.M. Raman and infrared spectra, normal coordinate analysis and ab initio calculations of 4-Amino-2-chloropyrimidine-5-carbonitrile. J. Mol. Struct. 2016;1115:85–93.

[3]Li M, Dong X, Xing T, Chen G. Anti-Wrinkle and Dyeing Properties of Silk Fabric Finished with 2,4,6-Trichloropyrimidine. Polymers (Basel). 2022 Aug 16;14(16):3332.