Table 3.

Activation constant (K_A) of the synthesised compounds and Clonidine (CLO) for human I, II, VA, VII and XIII Carbonic Anhydrase isoforms.

N	R1	X	R2	KA (μM)b
				hCA I	hCA II	hCA VA	hCA VII	hCA XIII
1a	H	S	–CH3	9.61	>150	38.3	41.9	>100
2	H	NH	–CH2Ph	4.18	>150	45.7	35.2	>100
3	H	NH	–(CH2)2Ph	>150	>150	16.7	18.9	>100
S-4	H	NH	(S)–CH(Me)Ph	>150	>150	12.4	31.5	>100
R-4	H	NH	(R)–CH(Me)Ph	>150	>150	4.92	24.2	>100
5	H	NH	–(CH2)3Ph	36.7	>100	9.9	11.4	24.3
6	H	NMe	–CH2Ph	>150	>150	40.5	11.0	>100
7	H	NMe	–(CH2)2Ph	68.6	>100	14.9	2.4	6.5
8	CH3	NH	–(CH2)2Ph	95.4	>100	14.6	16.2	31.0
9	CH3	NMe	–(CH2)2Ph	20.2	>100	14.9	2.6	36.9
10	CH3	NMe	–CH2Ph	30.2	>100	0.9	6.5	17.4
11	CH3	NH	–CH2Ph	16.9	>100	3.7	0.9	19.1
12	CH3	NH	–(CH2)3Ph	10.9	>100	17.2	3.1	10.9
13	CH3	NH	–CH2C6H4Cl(4)	17.7	>100	10.5	22.7	22.9
14	CH3	NH	–CH2C6H4OCH3(4)	37.6	>100	15.3	30.2	19.3
15	CH3	NH	–CH2C6H4F(4)	59.7	>100	9.3	17.4	24.4
16	CH3	NH	–CH2C6H4Cl(3)	99.2	>100	10.4	24.0	37.0
17	CH3	NH	–CH2C6H4OCH3(3)	>100	>100	13.1	29.4	14.7
18	CH3	NH	–CH2C6H4 F(3)	>100	>100	14.9	19.4	23.3
19	H	NH	–(CH2)2NHCH2Ph	>100	>100	11.0	41.7	20.1
20	CH3	NH	–(CH2)2NHCH2Ph	>100	>100	11.9	29.0	16.3
21	H	NH	–CH2CH2NH2	3.87	>150	31.2	91.6	>100
22	H	NH	–Ph	>150	>150	52.7	32.6	>100
23	COCH3	S	–CH3	12.7	>150	15.0	30.9	>100
24	H	S	–CH2Ph	>150	>150	11.1	46.7	>100
CLO	H	NH	(2,6-dichloro)Ph	76.3	>200	42.6	8.4	7.8

^aAll compounds have been tested as HI salts, with the exception of 21 (oxalate), 22 and 23 (free bases), 24 (HBr), and CLO (HCl).

^bMean from 3 different determinations (errors in the range of 5–10% of the reported values, data not shown).