Synthesis of 5-amino-1,3,4-thiadiazole-2-sulphonamide derivatives and their inhibition effects on human carbonic anhydrase isozymes

Figures & data

Figure 1.  Structures of several CA inhibitors used in glaucoma treatment.

Scheme 1.  Synthesis of title compound.

Scheme 2.  Synthesis of compounds 8-18.

Table 1.  IC₅₀ and K_i values of hCA-I and hCA-II isoenzyme hydratase and esterase activities obtained after the inhibition experiments.

İnhibitor	Hydratase IC50 (μM)		Esterase IC50 (μM)		Ki values (μM)
	hCA-I	hCA-II	hCA-I	hCA-II	hCA-I	hCA-II
1	3.35	2.75	2.8	7.4	2.7	3.5
2	4.2	4.02	3.5	7.9	3.3	7.75
8	2.86	2.4	4.75	2.1	5.83	0.848
9	0.2	0.8	0.23	0.03	0.095	0.018
10	0.27	0.18	0.35	0.05	0.36	0.056
11	0.33	0.08	0.57	0.13	0.572	0.103
12	0.164	0.16	1	0.37	1.532	0.244
13	0.7	1	4.8	1.42	1.018	3.184
14	1.32	1.3	0.8	0.85	1.532	0.498
15	1.21	0.8	0.91	0.14	1.19	0.125
16	0.85	1	0.38	0.07	0.3	0.065
17	0.78	0.2	0.33	0.08	0.31	0.108
18	0.75	0.6	2.4	1.74	6.671	3.916