In the presence of trifluoracetic acid (TFAA), an efficient method for the synthesis of tetra(hexa)hydropyrimidinethione-carboxylates has been used on the basis of three-component condensation of thiourea with its different aldehydes and -diketones. Some novel cyclic thioureas were synthesized, and their hCA I, hCA II, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibitors and metal-chelating properties were evaluated. K-i values of novel synthesized compounds for AChE and BChE are in the range of 51.84-135.96 and 143.96-274.55 nM, respectively. Also, HCA I and II were effectively inhibited by these novel compounds, with K-i values in the range of 404.16-745.13 nM for hCA I and of 434.20-689.57 nM for hCA II, respectively. Additionally, acetazolamide (AZA), clinically used as a CA inhibitor, with a K-i value of 883.68 +/- 121.27 nM in hCA I and 1008.66 +/- 144.70 nM in hCA II. Also, tacrine inhibited AChE and BChE showed K-i values of 314.63 +/- 31.66 and 373.57 +/- 75.07 nM, respectively.