Synthesis and Biological Evaluation of 2-Aminothiazole Analogues of Nα-Protected Amino Acids

Synthesis of 2-amino-thiazoles from Nα-protected bromomethyl ketones obtained from Nα-protected diazomethyl ketones has been reported in this study.N-protected amino acids were converted to diazomethylketones using (Benzotriazol-1-yloxy) tris (dimethylamino) phosphonium hexafluorophosphate (BOP) as carboxylic acid activator and N-nitroso-N-methyl urea (NMU) as diazomethane source. Thus, prepared diazomethylketones were treated with aqueous HBr to get bromomethyl ketones in high yields. The 2-amino-thiazoles of protected-amino acids were prepared by sonicating the bromomethyl ketones with thiourea in acetone, using Hantzsch’s procedure. The products were obtained in good yields and were fully characterized. The purity of the synthesized compounds was analyzed by collecting the RP-HPLC data for two sets of compounds. Kirby Bauer well diffusion technique was employed to test the antibacterial activity of the compounds, Boc-Arg-thiazole, Cbz-Asp-thiazole, Cbz-Trp-thiazole, Fmoc-Phe-thiazole, and Fmoc-Trp-thiazole. The test leads to the promising activity with Streptomycin sulfate as standard and the compound Fmoc-Phe-thiazole was susceptible to Staphylococcus aureus.