Synthesis and platelet aggregation inhibitory activity of 4,5-bis(aryl)-2-substituted-thiazoles

In our continuing effort to discover compound which inhibit collagen-induced platelet aggregation, we have screened compounds in a mouse pulmonary thromboembolism screen. Methyl 4,5-bis(4-methoxyphenyl)-2-thiazoleacetate (3) was very active in the above screen. However, 3 was active for less than 5 min when given orally to guinea pigs. As a result, our synthetic goal was to prepare 2-substituted thiazoles with a much longer duration of activity. This paper describes the preparation of a number 4,5-bis(aryl)-2-substituted-thiazoles and their in vitro and ex vivo activity against collagen-induced platelet aggregation. It was determined that 4,5-bis(4-methoxyphenyl)-2-(trifluoromethyl)thiazole (16) is the most promising compound.