1	8TX	8-thioxo-3,7,8,9-tetrahydro-1h-purine-2,6-dione	1.000
2	XAN	Xanthine	0.917
3	5JL	2,8-dithioxo-1,2,3,7,8,9-hexahydro-6h-purin-6-one	0.846
4	8HX	8-hydroxy-3,9-dihydro-1h-purine-2,6-dione	0.846
5	B55	2-amino-8-sulfanyl-1,9-dihydro-6h-purin-6-one	0.846
6	I7U	3-methyl-7~{H}-purine-2,6-dione	0.846
7	URC	Uric acid	0.846
8	HPA	Hypoxanthine	0.833
9	37T	Theobromine	0.786
10	MUA	9-methyl uric acid	0.786
11	TEP	Theophylline	0.786
12	290	6-methyl-3,9-dihydro-2h-purin-2-one	0.769
13	2ON	2-sulfanyl-1,9-dihydro-6h-purin-6-one	0.769
14	AZA	8-azaxanthine	0.769
15	BOA	2-bromo-6-hydroxy-purine	0.769
16	GUN	Guanine	0.769
17	IGA	6-amino-3,7-dihydro-2h-purin-2-one	0.769
18	KB5	6-azanyl-9~{H}-purine-8-thiol	0.769
19	WUT	9~{H}-purine	0.750
20	209	8-amino-1,3-dimethyl-3,7-dihydropurine-2,6-dione	0.733
21	8NX	8-nitro-3,7-dihydro-1h-purine-2,6-dione	0.733
22	A1BD3	Enprofylline	0.733
23	CFF	Caffeine	0.733
24	H33	8-chloro-1,3-dimethyl-3,7-dihydro-1h-purine-2,6-dione	0.733
25	IUP	5-(hydro)peroxoisourate	0.733
26	5JQ	2-thioxo-2,3,7,9-tetrahydro-1h-purine-6,8-dione	0.714
27	8IG	8-iodo-guanine	0.714
28	8WT	8-methylsulfanyl-7~{H}-purin-6-amine	0.714
29	9MG	9-methylguanine	0.714
30	A1LXN	2-azanyl-8-methyl-1,9-dihydropurin-6-one	0.714
31	ANG	8-aminoguanine	0.714
32	AZ8	Pyrimido[5,4-E][1,2,4]triazine-5,7(6h,8h)-dione	0.714
33	BRG	8-bromoguanine	0.714
34	LUZ	Pteridine-2,4(1h,3h)-dione	0.714
35	MY6	2-amino-7-methyl-1,7-dihydro-6h-purin-6-one	0.714
36	OXG	8-oxoguanine	0.714