1	KBQ	2-sulfanylidene-1,7-dihydropyrrolo[2,3-D]pyrimidin-4-one	1.000
2	7HX	7h-pyrrolo[2,3-D]pyrimidin-4-ol	0.909
3	2ON	2-sulfanyl-1,9-dihydro-6h-purin-6-one	0.833
4	7DG	7-deazaguanine	0.833
5	QY8	2-amino-3h,4h,7h-pyrrolo[2,3-D]pyrimidin-4-one	0.833
6	WOY	6,7-dihydro-5h-pyrrolo[2,3-D]pyrimidine	0.818
7	5JL	2,8-dithioxo-1,2,3,7,8,9-hexahydro-6h-purin-6-one	0.769
8	5JQ	2-thioxo-2,3,7,9-tetrahydro-1h-purine-6,8-dione	0.769
9	D1V	2-mercapto(3h)quinazolinone	0.769
10	FDB	2-amino-5-methyl-3h-pyrrolo[2,3-D]pyrimidin-4(7h)-one	0.769
11	HPA	Hypoxanthine	0.750
12	TUL	2-thioxo-2,3-dihydropyrimidin-4(1h)-one	0.727
13	GD1	2-amino-5-[(z)-iminomethyl]-3,7-dihydro-4h-pyrrolo[2,3-D]pyrimidin-4-one	0.714
14	HNG	2-amino-5-(aminomethyl)-1,7-dihydro-4h-pyrrolo[2,3-D]pyrimidin-4-one	0.714
15	PQ0	2-amino-4-oxo-4,7-dihydro-3h-pyrrolo[2,3-D]pyrimidine-5-carbonitrile	0.714
16	PRF	7-deaza-7-aminomethyl-guanine	0.714