Table 1. In Vitro Activity of 2,4-Disubstituted 5-Nitro-6-thiocyanatopyrimidines 63–112 against Cryptococcus neoformans and Cryptococcus gattii.

molecule no.	R1	R2	CC50 μM (μg/mL)	C. neoformans MIC80 μM (μg/mL)	C. gattia MIC80 μM (μg/mL)	C. neoformansa MIC80 (FLC-resistance) μM (μg/mL)
63	H	MeO		9.37 ± 3.12 (1.98 ± 0.66)	>25 (>5.3)
64	H	PrO	31.8 (7.64)	3.9 ± 0 (0.93 ± 0)	4.68 ± 1.56 (1.12 ± 0.38)
65	H	iPrO	23.3 (5.6)	1.9 ± 0 (0.45 ± 0)	1.17 ± 0.39 (0.27 ± 0.09)
66	H	NH2		4.68 ± 1.56 (0.92 ± 0.3)	1.17 ± 0.39 (0.22 ± 0.07)
67	H	iPrNH	12 (2.87)	2.34 ± 0.78 (0.55 ± 0.18)	0.58 ± 0.19 (0.13 ± 0.04)	2.34 ± 1.56 (0.55 ± 0.37)
68	H	3-methylbutan-2-yl-NH		3 ± 0 (0.8 ± 0)
69	H	pentan-3-yl-NH		18.5 ± 0 (4.94 ± 0)	>25 (>6.678)
70	H	cyclopentyl-NH		4.9 ± 0 (1.29 ± 0)	1.17 ± 0.39 (0.3 ± 0.1)	2.34 ± 1.56 (0.62 ± 0.41)
71	H	cyclohexyl-NH		6 ± 0 (1.67 ± 0)	1.17 ± 0.39 (0.32 ± 0.11)
72	H	piperidinyl	11.9 (3.16)	2.34 ± 0.78 (0.61 ± 0.2)	1.17 ± 0.39 (0.3 ± 0.1)	4.68 ± 3.13 (1.24 ± 0.83)
73	H	2-Me-piperidinyl		9.37 ± 3.12 (2.61 ± 0.86)	1.17 ± 0.39 (0.32 ± 0.11)
74	H	2,6-di-Me-piperidinyl		9.37 ± 3.12 (2.74 ± 0.9)	15.62 ± 9.37 (4.58 ± 2.75)
75	H	3,5-di-Me-piperidinyl	33.6 (9.86)	2.34 ± 0.78 (0.68 ± 0.22)	9.37 ± 3.12 (2.74 ± 0.91)
76	H	azepanyl	17.7 (4.94)	2.34 ± 0.78 (0.65 ± 0.22)	2.34 ± 0.78 (0.65 ± 0.22)	2.34 ± 1.56 (0.65 ± 0.43)
77	H	azocanyl		4.68 ± 1.56 (1.37 ± 0.46)	2.34 ± 0.78 (0.68 ± 0.23)
78	H	benzyl-NH	19.6 (5.63)	2.34 ± 0.78 (0.66 ± 0.22)	1.17 ± 0.39 (0.33 ± 0.11)	1.17 ± 0.78 (0.33 ± 0.22)
79	H	(mCF3-benzyl)-NH	25.91 (9.21)	9.37 ± 12.5 (3.32 ± 4.44)	4.68 ± 1.56 (1.66 ± 0.56)
80	H	(pCl-benzyl)-NH	22.53 (7.25)	5.85 ± 7.8 (1.88 ± 2.5)	1.17 ± 0.39 (0.37 ± 0.12)
81	H	Ph-(CH2)2-NH	15.09 (4.55)	3.51 ± 4.68 (1.05 ± 1.4)	2.34 ± 0.78 (0.7 ± 0.23)
82	H	Me2N		4.68 ± 1.56 (1.05 ± 0.34)	1.17 ± 0.39 (0.26 ± 0.09)
83	H	di-Et-N		9.37 ± 3.12 (2.37 ± 0.78)	0.14 ± 0.04 (0.03 ± 0.01)
84	H	iPrEtN	10.7 (2.86)	4.55 ± 4.24 (1.4 ± 1.12)	1.17 ± 0.39 (0.3 ± 0.1)
85	H	cyclohexylMeN	25.3 (7.42)	6 ± 0 (1.76 ± 0)	4.68 ± 1.56 (1.37 ± 0.46)
86	H	benzylMeN	18.8 (5.66)	2.34 ± 0.78 (0.7 ± 0.22)	1.17 ± 0.39 (0.35 ± 0.12)
87	H	benzyl-N-iPr		>50 (>16.46)	>25 (>8.23)
88	Me	EtO	19.8 (4.76)	1.17 ± 0.38 (0.27 ± 0.08)	0.29 ± 0.1 (0.06 ± 0.02)	2.34 ± 1.56 (0.56 ± 0.37)
89	Me	PrO	15.8 (4.02)	0.6 ± 0 (0.15 ± 0)	1.17 ± 0.39 (0.29 ± 0.1)	1.17 ± 0.78 (0.29 ± 0.19)
90	Me	iPrO	14.6 (3.71)	1 ± 0 (0.25 ± 0)	1.17 ± 0.39 (0.29 ± 0.1)	1.17 ± 0.78 (0.29 ± 0.19)
91	Me	NH2	24.5 (5.17)	2.34 ± 0.78 (0.48 ± 0.16)	0.58 ± 0.19 (0.12 ± 0.04)	2.34 ± 1.56 (0.49 ± 0.32)
92	Me	MeNH	>100 (>22.53)	2.34 ± 0.78 (0.52 ± 0.16)	1.17 ± 0.39 (0.26 ± 0.09)	2.34 ± 1.56 (0.52 ± 0.35)
93	Me	pentan-3-yl-NH		9 ± 0 (2.53 ± 0)	9.37 ± 3.12 (2.63 ± 0.88)
94	Me	cyclopropyl-NH	12.7 (3.19)	0.6 ± 0 (0.15 ± 0)	0.58 ± 0.19 (0.14 ± 0.05)	1.17 ± 0.78 (0.29 ± 0.19)
95	Me	cyclopentyl-NH		9 ± 0 (2.51 ± 0)	2.34 ± 0.78 (0.65 ± 0.22)
96	Me	cyclohexyl-NH		>50 (>24.62)	>25 (>12.31)
97	Me	pyrrolidinyl		4.68 ± 1.56 (1.23 ± 0.4)	1.17 ± 0.39 (0.3 ± 0.1)
98	Me	2-Me-piperidinyl		18.75 ± 6.24 (5.49 ± 1.82)	0.58 ± 0.19 (0.16 ± 0.05)
99	Me	3,5-di-Me-piperidinyl		18.75 ± 6.24 (5.76 ± 1.92)	9.37 ± 3.12 (2.88 ± 0.96)
100	Me	azepanyl		18.75 ± 6.24 (5.49 ± 1.82)	4.68 ± 1.56 (1.37 ± 0.46)
101	Me	azocanyl		18.75 ± 6.24 (5.76 ± 1.92)	2.34 ± 0.78 (0.71 ± 0.24)
102	Me	benzyl-NH	15.87 (4.78)	50 ± 0 (15.06 ± 0)	18.75 ± 6.25 (5.64 ± 1.88)
103	Me	(pMe-benzyl)-NH	14.73 (4.65)	50 ± 0 (15.76 ± 0)	1.17 ± 0.39 (0.36 ± 0.12)
104	Me	Ph-(CH2)2-NH	12.27 (3.87)	50 ± 0 (15.76 ± 0)	2.34 ± 0.78 (0.73 ± 0.24)
105	Me	Me2N		4.68 ± 1.56 (1.11 ± 0.36)	2.34 ± 0.78 (0.55 ± 0.18)
106	Me	di-Et-N		9.37 ± 3.12 (2.5 ± 0.82)	2.34 ± 0.78 (0.62 ± 0.21)
107	SMe	benzyl-NH	18.59 (6.2)	4.68 ± 4.68 (1.56 ± 1.56)	4.68 ± 1.56 (1.56 ± 0.52)
108	SMe	(pMe-benzyl)-NH	19.2 (6.67)	9.37 ± 3.12 (3.25 ± 1.08)	4.68 ± 1.56 (1.62 ± 0.54)
109	SMe	Ph-(CH2)2-NH	15.39 (5.35)	9.37 ± 9.36 (3.25 ± 3.24)	1.17 ± 0.39 (0.4 ± 0.13)
110	CF3	iPrNH	42.8 (13.15)	12.25 ± 6.5 (4.4 ± 2)	>25 (>7.68)	18.75 ± 12.5 (5.76 ± 3.84)
111	Ph	iPrNH		50 ± 0 (15.76 ± 0)
112	styryl	MeNH		>50 (>15.66)	>25 (>7.83)

^aThe C. neoformans fluconazole-resistant DUMC-158.03, and C. gattii, RSA-3615, clinical strains were obtained from Dr. John Perfect, Duke University.⁴⁰