1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene

C237H354F20O10 — CID 158742771

About 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene

1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene (PubChem CID 158742771) has the molecular formula C237H354F20O10 and a molecular weight of 3743.39 g/mol. Its IUPAC name is 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene.

Molecular Properties

• Compound Name: 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene
• PubChem CID: 158742771
• Molecular Formula: C237H354F20O10
• Molecular Weight: 3743.39 g/mol
• Exact Mass: 3740.69
• IUPAC Name: 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene
• SMILES: CCC1CCC(C2CCC(c3ccc(OC)c(F)c3F)CC2)CC1.CCCCCCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.COc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F
• InChI: InChI=1S/C28H44F2O.C27H42F2O.C26H40F2O.C25H38F2O.C24H36F2O.C23H34F2O.C22H32F2O.2C21H30F2O.C20H28F2O/c1-3-4-5-6-7-8-9-20-31-26-19-18-25(27(29)28(26)30)24-16-14-23(15-17-24)22-12-10-21(2)11-13-22;1-3-4-5-6-7-8-19-30-25-18-17-24(26(28)27(25)29)23-15-13-22(14-16-23)21-11-9-20(2)10-12-21;1-3-4-5-6-7-18-29-24-17-16-23(25(27)26(24)28)22-14-12-21(13-15-22)20-10-8-19(2)9-11-20;1-3-4-5-6-17-28-23-16-15-22(24(26)25(23)27)21-13-11-20(12-14-21)19-9-7-18(2)8-10-19;1-3-4-5-16-27-22-15-14-21(23(25)24(22)26)20-12-10-19(11-13-20)18-8-6-17(2)7-9-18;1-3-4-15-26-21-14-13-20(22(24)23(21)25)19-11-9-18(10-12-19)17-7-5-16(2)6-8-17;1-3-14-25-20-13-12-19(21(23)22(20)24)18-10-8-17(9-11-18)16-6-4-15(2)5-7-16;1-3-14-4-6-15(7-5-14)16-8-10-17(11-9-16)18-12-13-19(24-2)21(23)20(18)22;1-3-24-19-13-12-18(20(22)21(19)23)17-10-8-16(9-11-17)15-6-4-14(2)5-7-15;1-13-3-5-14(6-4-13)15-7-9-16(10-8-15)17-11-12-18(23-2)20(22)19(17)21/h18-19,21-24H,3-17,20H2,1-2H3;17-18,20-23H,3-16,19H2,1-2H3;16-17,19-22H,3-15,18H2,1-2H3;15-16,18-21H,3-14,17H2,1-2H3;14-15,17-20H,3-13,16H2,1-2H3;13-14,16-19H,3-12,15H2,1-2H3;12-13,15-18H,3-11,14H2,1-2H3;2*12-17H,3-11H2,1-2H3;11-16H,3-10H2,1-2H3
• InChIKey: IMMUHIRJHIMJHZ-UHFFFAOYSA-N
• XLogP: 75.17
• TPSA: 92.30 Ų
• H-Bond Acceptors: 10
• Rotatable Bonds: 67
• Heavy Atoms: 267
• Complexity: —

Lipinski Rule of Five

2 violations

Rule	Value
MW ≤ 500	3743.39
LogP ≤ 5	75.17
H-Bond Donors ≤ 5	0
H-Bond Acceptors ≤ 10	10

Computed Properties (RDKit)

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

Frequently Asked Questions

What is the IUPAC name of 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene?

The IUPAC name of 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene (CID 158742771) is 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene.

What is the SMILES notation for 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene?

The canonical SMILES for 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene is CCC1CCC(C2CCC(c3ccc(OC)c(F)c3F)CC2)CC1.CCCCCCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.CCOc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.COc1ccc(C2CCC(C3CCC(C)CC3)CC2)c(F)c1F.

What is the InChIKey of 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene?

The InChIKey is IMMUHIRJHIMJHZ-UHFFFAOYSA-N. The full InChI is InChI=1S/C28H44F2O.C27H42F2O.C26H40F2O.C25H38F2O.C24H36F2O.C23H34F2O.C22H32F2O.2C21H30F2O.C20H28F2O/c1-3-4-5-6-7-8-9-20-31-26-19-18-25(27(29)28(26)30)24-16-14-23(15-17-24)22-12-10-21(2)11-13-22;1-3-4-5-6-7-8-19-30-25-18-17-24(26(28)27(25)29)23-15-13-22(14-16-23)21-11-9-20(2)10-12-21;1-3-4-5-6-7-18-29-24-17-16-23(25(27)26(24)28)22-14-12-21(13-15-22)20-10-8-19(2)9-11-20;1-3-4-5-6-17-28-23-16-15-22(24(26)25(23)27)21-13-11-20(12-14-21)19-9-7-18(2)8-10-19;1-3-4-5-16-27-22-15-14-21(23(25)24(22)26)20-12-10-19(11-13-20)18-8-6-17(2)7-9-18;1-3-4-15-26-21-14-13-20(22(24)23(21)25)19-11-9-18(10-12-19)17-7-5-16(2)6-8-17;1-3-14-25-20-13-12-19(21(23)22(20)24)18-10-8-17(9-11-18)16-6-4-15(2)5-7-16;1-3-14-4-6-15(7-5-14)16-8-10-17(11-9-16)18-12-13-19(24-2)21(23)20(18)22;1-3-24-19-13-12-18(20(22)21(19)23)17-10-8-16(9-11-17)15-6-4-14(2)5-7-15;1-13-3-5-14(6-4-13)15-7-9-16(10-8-15)17-11-12-18(23-2)20(22)19(17)21/h18-19,21-24H,3-17,20H2,1-2H3;17-18,20-23H,3-16,19H2,1-2H3;16-17,19-22H,3-15,18H2,1-2H3;15-16,18-21H,3-14,17H2,1-2H3;14-15,17-20H,3-13,16H2,1-2H3;13-14,16-19H,3-12,15H2,1-2H3;12-13,15-18H,3-11,14H2,1-2H3;2*12-17H,3-11H2,1-2H3;11-16H,3-10H2,1-2H3.

What are the key properties of 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene?

1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene has a molecular weight of 3743.39 g/mol, XLogP of 75.17, 67 rotatable bonds, 0 hydrogen bond donors, and 10 hydrogen bond acceptors.

Where does this data come from?

All data for 1-butoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-heptoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-hexoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-methoxy-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-nonoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-octoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-pentoxybenzene;2,3-difluoro-1-[4-(4-methylcyclohexyl)cyclohexyl]-4-propoxybenzene;1-ethoxy-2,3-difluoro-4-[4-(4-methylcyclohexyl)cyclohexyl]benzene;1-[4-(4-ethylcyclohexyl)cyclohexyl]-2,3-difluoro-4-methoxybenzene is sourced from PubChem (CID 158742771), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).