2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol

C127H145Cl4F8N37O7 — CID 172962505

About 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol

2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol (PubChem CID 172962505) has the molecular formula C127H145Cl4F8N37O7 and a molecular weight of 2595.60 g/mol. Its IUPAC name is 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol.

Molecular Properties

• Compound Name: 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol
• PubChem CID: 172962505
• Molecular Formula: C127H145Cl4F8N37O7
• Molecular Weight: 2595.60 g/mol
• Exact Mass: 2592.08
• IUPAC Name: 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol
• SMILES: CN1CCN(Cc2ccc(-c3cc(Cl)c(O)c(/C=N/Nc4ncc(F)c(N5CCN(CCO)CC5)n4)c3)cc2)CC1.CN1CCN(Cc2ccc(-c3ccnc(/C=N/Nc4ncc(F)c(N5CCN(CCO)CC5)n4)c3)cc2)CC1.Cc1cccc(Cl)c1-c1cc(Cl)c(O)c(/C=N/Nc2ncc(F)c(N3CCN(CCO)CC3)n2)c1.Cc1cccc(Cl)c1-c1ccnc(/C=N/Nc2ncc(F)c(N3CCN(CCO)CC3)n2)c1.OCCN1CCN(c2nc(N/N=C/c3ccc(-c4cccc(C(F)(F)F)c4)cn3)ncc2F)CC1
• InChI: InChI=1S/C29H36ClFN8O2.C28H36FN9O.C24H25Cl2FN6O2.C23H25ClFN7O.C23H23F4N7O/c1-36-6-8-38(9-7-36)20-21-2-4-22(5-3-21)23-16-24(27(41)25(30)17-23)18-33-35-29-32-19-26(31)28(34-29)39-12-10-37(11-13-39)14-15-40;1-35-8-10-37(11-9-35)21-22-2-4-23(5-3-22)24-6-7-30-25(18-24)19-32-34-28-31-20-26(29)27(33-28)38-14-12-36(13-15-38)16-17-39;1-15-3-2-4-18(25)21(15)16-11-17(22(35)19(26)12-16)13-29-31-24-28-14-20(27)23(30-24)33-7-5-32(6-8-33)9-10-34;1-16-3-2-4-19(24)21(16)17-5-6-26-18(13-17)14-28-30-23-27-15-20(25)22(29-23)32-9-7-31(8-10-32)11-12-33;24-20-15-29-22(31-21(20)34-8-6-33(7-9-34)10-11-35)32-30-14-19-5-4-17(13-28-19)16-2-1-3-18(12-16)23(25,26)27/h2-5,16-19,40-41H,6-15,20H2,1H3,(H,32,34,35);2-7,18-20,39H,8-17,21H2,1H3,(H,31,33,34);2-4,11-14,34-35H,5-10H2,1H3,(H,28,30,31);2-6,13-15,33H,7-12H2,1H3,(H,27,29,30);1-5,12-15,35H,6-11H2,(H,29,31,32)/b33-18+;32-19+;29-13+;28-14+;30-14+
• InChIKey: CBOGAGSVBIWRGB-NDUPUGNLSA-N
• XLogP: 15.56
• TPSA: 476.49 Ų
• H-Bond Donors: 12
• H-Bond Acceptors: 44
• Rotatable Bonds: 39
• Heavy Atoms: 183
• Complexity: —

Lipinski Rule of Five

4 violations

Rule	Value
MW ≤ 500	2595.60
LogP ≤ 5	15.56
H-Bond Donors ≤ 5	12
H-Bond Acceptors ≤ 10	44

Computed Properties (RDKit)

• Structural Alerts: {'alert_name': 'hzone_phenol_A(479)', 'substructure': 'N/A'}, {'alert_name': 'imine_1', 'substructure': 'N/A'}, {'alert_name': 'Oxygen-nitrogen_single_bond', 'substructure': 'N/A'}

Frequently Asked Questions

What is the IUPAC name of 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol?

The IUPAC name of 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol (CID 172962505) is 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol.

What is the SMILES notation for 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol?

The canonical SMILES for 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol is CN1CCN(Cc2ccc(-c3cc(Cl)c(O)c(/C=N/Nc4ncc(F)c(N5CCN(CCO)CC5)n4)c3)cc2)CC1.CN1CCN(Cc2ccc(-c3ccnc(/C=N/Nc4ncc(F)c(N5CCN(CCO)CC5)n4)c3)cc2)CC1.Cc1cccc(Cl)c1-c1cc(Cl)c(O)c(/C=N/Nc2ncc(F)c(N3CCN(CCO)CC3)n2)c1.Cc1cccc(Cl)c1-c1ccnc(/C=N/Nc2ncc(F)c(N3CCN(CCO)CC3)n2)c1.OCCN1CCN(c2nc(N/N=C/c3ccc(-c4cccc(C(F)(F)F)c4)cn3)ncc2F)CC1.

What is the InChIKey of 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol?

The InChIKey is CBOGAGSVBIWRGB-NDUPUGNLSA-N. The full InChI is InChI=1S/C29H36ClFN8O2.C28H36FN9O.C24H25Cl2FN6O2.C23H25ClFN7O.C23H23F4N7O/c1-36-6-8-38(9-7-36)20-21-2-4-22(5-3-21)23-16-24(27(41)25(30)17-23)18-33-35-29-32-19-26(31)28(34-29)39-12-10-37(11-13-39)14-15-40;1-35-8-10-37(11-9-35)21-22-2-4-23(5-3-22)24-6-7-30-25(18-24)19-32-34-28-31-20-26(29)27(33-28)38-14-12-36(13-15-38)16-17-39;1-15-3-2-4-18(25)21(15)16-11-17(22(35)19(26)12-16)13-29-31-24-28-14-20(27)23(30-24)33-7-5-32(6-8-33)9-10-34;1-16-3-2-4-19(24)21(16)17-5-6-26-18(13-17)14-28-30-23-27-15-20(25)22(29-23)32-9-7-31(8-10-32)11-12-33;24-20-15-29-22(31-21(20)34-8-6-33(7-9-34)10-11-35)32-30-14-19-5-4-17(13-28-19)16-2-1-3-18(12-16)23(25,26)27/h2-5,16-19,40-41H,6-15,20H2,1H3,(H,32,34,35);2-7,18-20,39H,8-17,21H2,1H3,(H,31,33,34);2-4,11-14,34-35H,5-10H2,1H3,(H,28,30,31);2-6,13-15,33H,7-12H2,1H3,(H,27,29,30);1-5,12-15,35H,6-11H2,(H,29,31,32)/b33-18+;32-19+;29-13+;28-14+;30-14+.

What are the key properties of 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol?

2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol has a molecular weight of 2595.60 g/mol, XLogP of 15.56, 39 rotatable bonds, 12 hydrogen bond donors, and 44 hydrogen bond acceptors.

Where does this data come from?

All data for 2-chloro-4-(2-chloro-6-methylphenyl)-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]phenol;2-chloro-6-[(E)-[[5-fluoro-4-[4-(2-hydroxyethyl)piperazin-1-yl]pyrimidin-2-yl]hydrazinylidene]methyl]-4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]phenol;2-[4-[2-[(2E)-2-[[4-(2-chloro-6-methylphenyl)-2-pyridinyl]methylidene]hydrazinyl]-5-fluoropyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[4-[4-[(4-methylpiperazin-1-yl)methyl]phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol;2-[4-[5-fluoro-2-[(2E)-2-[[5-[3-(trifluoromethyl)phenyl]-2-pyridinyl]methylidene]hydrazinyl]pyrimidin-4-yl]piperazin-1-yl]ethanol is sourced from PubChem (CID 172962505), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).