1	CFF	Caffeine	1.000
2	EXU	1,3,7-trimethyl-9h-purine-2,6,8-trione	0.933
3	37T	Theobromine	0.929
4	TEP	Theophylline	0.929
5	E7R	1,3-dimethyl-7-propyl-purine-2,6-dione	0.875
6	209	8-amino-1,3-dimethyl-3,7-dihydropurine-2,6-dione	0.867
7	H33	8-chloro-1,3-dimethyl-3,7-dihydro-1h-purine-2,6-dione	0.867
8	7UM	3-methyl-7-propyl-purine-2,6-dione	0.812
9	XAN	Xanthine	0.786
10	X0T	7-[(2s)-2,3-dihydroxypropyl]-1,3-dimethyl-3,7-dihydro-1h-purine-2,6-dione	0.778
11	IBM	3-isobutyl-1-methylxanthine	0.765
12	7UH	Doxofylline	0.737
13	M1D	4-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-7h-purin-7-yl)butanoic acid	0.737
14	QOK	7-(2-methoxyethoxymethyl)-1,3-dimethyl-purine-2,6-dione	0.737
15	8HX	8-hydroxy-3,9-dihydro-1h-purine-2,6-dione	0.733
16	8TX	8-thioxo-3,7,8,9-tetrahydro-1h-purine-2,6-dione	0.733
17	MY6	2-amino-7-methyl-1,7-dihydro-6h-purin-6-one	0.733
18	URC	Uric acid	0.733
19	HPA	Hypoxanthine	0.714
20	PNX	3,7-dimethyl-1-(5-oxohexyl)-3,7-dihydro-1h-purine-2,6-dione	0.700