1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine

C146H109F5N44O14S6 — CID 160634716

About 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine

1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine (PubChem CID 160634716) has the molecular formula C146H109F5N44O14S6 and a molecular weight of 2991.16 g/mol. Its IUPAC name is 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine.

Molecular Properties

• Compound Name: 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine
• PubChem CID: 160634716
• Molecular Formula: C146H109F5N44O14S6
• Molecular Weight: 2991.16 g/mol
• Exact Mass: 2988.74
• IUPAC Name: 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine
• SMILES: COc1ccc(-c2ccc3ncc(S(=O)(=O)n4ncc5ncc(-c6cnn(C)c6)cc54)n3c2)cc1.Cc1ccc(-c2ccc3ncc(S(=O)(=O)n4ncc5ncc(-c6cnn(C)c6)cc54)n3c2)cc1.Cn1cc(-c2cnc3cnn(S(=O)(=O)c4cnc5ccc(-c6cc(F)c(F)c(F)c6)cn45)c3c2)cn1.Cn1cc(-c2cnc3cnn(S(=O)(=O)c4cnc5ccc(-c6ccc(C#N)cc6)cn45)c3c2)cn1.Cn1cc(-c2cnc3cnn(S(=O)(=O)c4cnc5ccc(-c6ccc(CN7CCOCC7)cc6)cn45)c3c2)cn1.Cn1cc(-c2cnc3cnn(S(=O)(=O)c4cnc5ccc(-c6ccc(F)cc6F)cn45)c3c2)cn1
• InChI: InChI=1S/C28H26N8O3S.C24H16N8O2S.C24H19N7O3S.C24H19N7O2S.C23H14F3N7O2S.C23H15F2N7O2S/c1-33-18-24(14-31-33)23-12-26-25(29-13-23)15-32-36(26)40(37,38)28-16-30-27-7-6-22(19-35(27)28)21-4-2-20(3-5-21)17-34-8-10-39-11-9-34;1-30-14-20(11-28-30)19-8-22-21(26-10-19)12-29-32(22)35(33,34)24-13-27-23-7-6-18(15-31(23)24)17-4-2-16(9-25)3-5-17;1-29-14-19(11-27-29)18-9-22-21(25-10-18)12-28-31(22)35(32,33)24-13-26-23-8-5-17(15-30(23)24)16-3-6-20(34-2)7-4-16;1-16-3-5-17(6-4-16)18-7-8-23-26-13-24(30(23)15-18)34(32,33)31-22-9-19(10-25-21(22)12-28-31)20-11-27-29(2)14-20;1-31-11-16(8-29-31)15-6-20-19(27-7-15)9-30-33(20)36(34,35)22-10-28-21-3-2-13(12-32(21)22)14-4-17(24)23(26)18(25)5-14;1-30-12-16(9-28-30)15-6-21-20(26-8-15)10-29-32(21)35(33,34)23-11-27-22-5-2-14(13-31(22)23)18-4-3-17(24)7-19(18)25/h2-7,12-16,18-19H,8-11,17H2,1H3;2-8,10-15H,1H3;3-15H,1-2H3;3-15H,1-2H3;2-12H,1H3;2-13H,1H3
• InChIKey: RIJSMVWTWJHHKZ-UHFFFAOYSA-N
• XLogP: 21.02
• TPSA: 645.31 Ų
• H-Bond Acceptors: 58
• Rotatable Bonds: 27
• Heavy Atoms: 215
• Complexity: —

Lipinski Rule of Five

3 violations

Rule	Value
MW ≤ 500	2991.16
LogP ≤ 5	21.02
H-Bond Donors ≤ 5	0
H-Bond Acceptors ≤ 10	58

Computed Properties (RDKit)

• Structural Alerts: {'alert_name': 'halogenated_ring_2', 'substructure': 'N/A'}

Frequently Asked Questions

What is the IUPAC name of 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine?

The IUPAC name of 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine (CID 160634716) is 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine.

What is the SMILES notation for 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine?

The canonical SMILES for 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine is COc1ccc(-c2ccc3ncc(S(=O)(=O)n4ncc5ncc(-c6cnn(C)c6)cc54)n3c2)cc1.Cc1ccc(-c2ccc3ncc(S(=O)(=O)n4ncc5ncc(-c6cnn(C)c6)cc54)n3c2)cc1.Cn1cc(-c2cnc3cnn(S(=O)(=O)c4cnc5ccc(-c6cc(F)c(F)c(F)c6)cn45)c3c2)cn1.Cn1cc(-c2cnc3cnn(S(=O)(=O)c4cnc5ccc(-c6ccc(C#N)cc6)cn45)c3c2)cn1.Cn1cc(-c2cnc3cnn(S(=O)(=O)c4cnc5ccc(-c6ccc(CN7CCOCC7)cc6)cn45)c3c2)cn1.Cn1cc(-c2cnc3cnn(S(=O)(=O)c4cnc5ccc(-c6ccc(F)cc6F)cn45)c3c2)cn1.

What is the InChIKey of 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine?

The InChIKey is RIJSMVWTWJHHKZ-UHFFFAOYSA-N. The full InChI is InChI=1S/C28H26N8O3S.C24H16N8O2S.C24H19N7O3S.C24H19N7O2S.C23H14F3N7O2S.C23H15F2N7O2S/c1-33-18-24(14-31-33)23-12-26-25(29-13-23)15-32-36(26)40(37,38)28-16-30-27-7-6-22(19-35(27)28)21-4-2-20(3-5-21)17-34-8-10-39-11-9-34;1-30-14-20(11-28-30)19-8-22-21(26-10-19)12-29-32(22)35(33,34)24-13-27-23-7-6-18(15-31(23)24)17-4-2-16(9-25)3-5-17;1-29-14-19(11-27-29)18-9-22-21(25-10-18)12-28-31(22)35(32,33)24-13-26-23-8-5-17(15-30(23)24)16-3-6-20(34-2)7-4-16;1-16-3-5-17(6-4-16)18-7-8-23-26-13-24(30(23)15-18)34(32,33)31-22-9-19(10-25-21(22)12-28-31)20-11-27-29(2)14-20;1-31-11-16(8-29-31)15-6-20-19(27-7-15)9-30-33(20)36(34,35)22-10-28-21-3-2-13(12-32(21)22)14-4-17(24)23(26)18(25)5-14;1-30-12-16(9-28-30)15-6-21-20(26-8-15)10-29-32(21)35(33,34)23-11-27-22-5-2-14(13-31(22)23)18-4-3-17(24)7-19(18)25/h2-7,12-16,18-19H,8-11,17H2,1H3;2-8,10-15H,1H3;3-15H,1-2H3;3-15H,1-2H3;2-12H,1H3;2-13H,1H3.

What are the key properties of 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine?

1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine has a molecular weight of 2991.16 g/mol, XLogP of 21.02, 27 rotatable bonds, 0 hydrogen bond donors, and 58 hydrogen bond acceptors.

Where does this data come from?

All data for 1-[6-(2,4-difluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;1-[6-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]sulfonyl-6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridine;4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]benzonitrile;4-[[4-[3-[6-(1-methylpyrazol-4-yl)pyrazolo[4,5-b]pyridin-1-yl]sulfonylimidazo[1,2-a]pyridin-6-yl]phenyl]methyl]morpholine;6-(1-methylpyrazol-4-yl)-1-[6-(3,4,5-trifluorophenyl)imidazo[1,2-a]pyridin-3-yl]sulfonylpyrazolo[4,5-b]pyridine is sourced from PubChem (CID 160634716), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).