Studies On The Synthesis And Cytotoxicity Of Dasatinib Analogues As Pan-Src Kinase Inhibitor

At present the focus of anticancer drug is moving from traditional cytotoxic drugs to new anticancer drugs, targeting tumor cells transductional pathway of signal. Tyrosine pro tein kinases has been shown to induce a wide variety of tumor cells by several mechanisms mainly including exerting important modulatory effection the proliferation, differentiation, mi grateon and metabolism-related singal transduction pathways in cells. Tyrosine kinase inhibitor has been developed as a new kind of antitumor drug in recent years, and Dasatini b is a representative drug of Tyrosine kinase inhibitor in clinic. This article summarized the research progresseson the drugs of anticancer and Tyrosine kinase inhibitor, especially the research progresses on the synthesis of Dasatinib and 2-aminothiazole-5-carboxylates. Using Dastinib as a leading compound, ten compounds were designed, synthesized, and evaluated for their cytotoxity activities. The main contents of this paper as follws:1. P-Ethoxy-2-propenoyl Chloride is an important intermediate in this synthetic route. Afte comparing the four routes in literatures, this synthetic route was chosed and imp roved as: Vinyl ether and Oxalyl chlorideas starting material, according to the procedure of addition reaction at Low-temperature, which decarbonylate upon distillation to give theβ-eth oxy-2-propenoyl chloride, the yield was 70 %. This process is suitable for large-scale prepar ation because of easy availabe raw material. Another structure of byproduct was recognizedas single ethyl oxalyl chloride. By studying the process, we summarize that decarbonization at 120℃giving toβ-Ethoxy-2-propenoyl, however, if the temperature was over 130℃, the main obtaining was single ethyl oxalyl chloride. Above method of preparing single ethyl oxalyl chloride has never been reported in any article, is suitable for large-scale preparation.2. 2-Amino-N-(2-Chloro-6-methylphenyl)-5-thiazolecarboxamide is an important int ermediate in this synthetic route. After comparing the literatures, this synthetic route was chosed andimproved as: To a mixture of N-(2-Chloro-6-methylphenyl)-3-ethoyacrylamide in water and dioxane V(1:1) at 0℃was added NBS as three equals. The reaction mixture was stirred at 0℃for 3 h and thiourea was added and the reaction mixture was heated to reflux for 0.5 h. Finally, the reaction mixture was adjusted pH to 10 by using NH₄OH. The precipitation was filtered to give 2-amino-N-(2-chloro-6-methylphenyl)-5-thiazolecarboxam ide with 93% yield. This procedure is suitable for large-scale preparation.3. In the process of designing the target compounds, Dasatinib applied in clinic were dissected and hybrided. In the end the frame segment 2-aminothiazole-5-carboxylates was preserved, acylamide bond was introduced.Then the main molecule frame was decoratedwith different groups,to give series of Dasatinib analogues. The Structural modification of compounds included two aspects: changing substituent hydroxylethyl-piperazine and improvin gwater-soluble. Therefore, ten target compounds and one intermediate were synthezied, andconfirmed by IR, ¹HNMR and EI-MS, ESI-MS.4. 2-(2-Chloroacetylacetamide)-N-(2-chloro-6-methylphenyl)-5-thiazolecar-boxamide, a common intermediate for the synthesis of compounds 1～7, was synthesized from 2-amino -N-(2-chloro-6-methylphenyl)-5-thiazolecarboxamide by treating with chloroacetyl chloride, and then subjected to amination with different amines to target compounds 1～7, The target compounds 8～10 were synthesized by treating 2-amino-N-(2-chloro-6-methylphenyl)-5-thiazol ecarboxamide with maleic anhydride, succinic anhydride, or NH₄SCN, respective with satisfactory yields.5. Ten target compounds were tested for antitumor activity in vitro against mouse hepatocarcinoma cell H22 by means of colorimetric MTT assay. The preliminary resultssuggested the target compounds showed some antitumoractivity at 10μM concentration. The further anticancer activity is under the way.6. As another part of this thesis, a practical synthesis of N-aryl-2,4-dioxo-5-thiazo lidinecarboxamides was developed in six sequential steps from diethyl malonate consisting of hydrolysis, chlorination, acylation, bromination, cyclization and so on. The 2,4-dioxo-5-thiazo lidinecarboxamide fragment could be successfully produced via the cyclization of 2-bromo-3-ethoxy-3-oxo-N-arylpropanamides with thiourea, and then hydrolysis in HCl-ethanol solution with satisfactory yield. This synthetic route provides an efficient access to prepare N-substitu ted-2,4-dioxo-5-thiazolidinecarboxamides.