[4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride

C109H137ClF6N22O23S2 — CID 161083464

About [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride

[4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride (PubChem CID 161083464) has the molecular formula C109H137ClF6N22O23S2 and a molecular weight of 2337.00 g/mol. Its IUPAC name is [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride.

Molecular Properties

• Compound Name: [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride
• PubChem CID: 161083464
• Molecular Formula: C109H137ClF6N22O23S2
• Molecular Weight: 2337.00 g/mol
• Exact Mass: 2334.93
• IUPAC Name: [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride
• SMILES: C.C.C.C#CC1(N[S@@](=O)C(C)(C)C)COC1.CC(C)(C)C(=O)OCn1cc(C2(C[S@@](=O)C(C)(C)C)COC2)nn1.CC(C)(C)C(=O)OCn1cc(C2(N)COC2)nn1.Cc1c(C(=O)C(=O)NC2(c3cn(COC(=O)C(C)(C)C)nn3)COC2)c2n(c1C(=O)Nc1ccc(F)c(F)c1)[C@@H]1C[C@@H]1C2.Cc1c(C(=O)C(=O)NC2(c3cn[nH]n3)COC2)c2n(c1C(=O)Nc1ccc(F)c(F)c1)[C@@H]1C[C@@H]1C2.Cc1c(C(=O)C(=O)O)c2n(c1C(=O)Nc1ccc(F)c(F)c1)[C@@H]1C[C@@H]1C2.Cl
• InChI: InChI=1S/C29H30F2N6O6.C23H20F2N6O4.C18H14F2N2O4.C16H27N3O4S.C11H18N4O3.C9H15NO2S.3CH4.ClH/c1-14-22(20-8-15-7-19(15)37(20)23(14)25(39)32-16-5-6-17(30)18(31)9-16)24(38)26(40)33-29(11-42-12-29)21-10-36(35-34-21)13-43-27(41)28(2,3)4;1-10-18(20(32)22(34)28-23(8-35-9-23)17-7-26-30-29-17)16-5-11-4-15(11)31(16)19(10)21(33)27-12-2-3-13(24)14(25)6-12;1-7-14(16(23)18(25)26)13-5-8-4-12(8)22(13)15(7)17(24)21-9-2-3-10(19)11(20)6-9;1-14(2,3)13(20)23-11-19-7-12(17-18-19)16(8-22-9-16)10-24(21)15(4,5)6;1-10(2,3)9(16)18-7-15-4-8(13-14-15)11(12)5-17-6-11;1-5-9(6-12-7-9)10-13(11)8(2,3)4;;;;/h5-6,9-10,15,19H,7-8,11-13H2,1-4H3,(H,32,39)(H,33,40);2-3,6-7,11,15H,4-5,8-9H2,1H3,(H,27,33)(H,28,34)(H,26,29,30);2-3,6,8,12H,4-5H2,1H3,(H,21,24)(H,25,26);7H,8-11H2,1-6H3;4H,5-7,12H2,1-3H3;1,10H,6-7H2,2-4H3;3*1H4;1H/t15-,19-;11-,15-;8-,12-;24-;;13-;;;;/m1111.0..../s1
• InChIKey: MDPWKMKNFNXNSQ-OUMKSHMESA-N
• XLogP: 11.72
• TPSA: 579.74 Ų
• H-Bond Donors: 9
• H-Bond Acceptors: 37
• Rotatable Bonds: 28
• Heavy Atoms: 163
• Complexity: —

Lipinski Rule of Five

4 violations

Rule	Value
MW ≤ 500	2337.00
LogP ≤ 5	11.72
H-Bond Donors ≤ 5	9
H-Bond Acceptors ≤ 10	37

Computed Properties (RDKit)

• Structural Alerts: {'alert_name': '>_2_ester_groups', 'substructure': 'N/A'}, {'alert_name': 'diketo_group', 'substructure': 'N/A'}, {'alert_name': 'triple_bond', 'substructure': 'N/A'}

Frequently Asked Questions

What is the IUPAC name of [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride?

The IUPAC name of [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride (CID 161083464) is [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride.

What is the SMILES notation for [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride?

The canonical SMILES for [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride is C.C.C.C#CC1(N[S@@](=O)C(C)(C)C)COC1.CC(C)(C)C(=O)OCn1cc(C2(C[S@@](=O)C(C)(C)C)COC2)nn1.CC(C)(C)C(=O)OCn1cc(C2(N)COC2)nn1.Cc1c(C(=O)C(=O)NC2(c3cn(COC(=O)C(C)(C)C)nn3)COC2)c2n(c1C(=O)Nc1ccc(F)c(F)c1)[C@@H]1C[C@@H]1C2.Cc1c(C(=O)C(=O)NC2(c3cn[nH]n3)COC2)c2n(c1C(=O)Nc1ccc(F)c(F)c1)[C@@H]1C[C@@H]1C2.Cc1c(C(=O)C(=O)O)c2n(c1C(=O)Nc1ccc(F)c(F)c1)[C@@H]1C[C@@H]1C2.Cl.

What is the InChIKey of [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride?

The InChIKey is MDPWKMKNFNXNSQ-OUMKSHMESA-N. The full InChI is InChI=1S/C29H30F2N6O6.C23H20F2N6O4.C18H14F2N2O4.C16H27N3O4S.C11H18N4O3.C9H15NO2S.3CH4.ClH/c1-14-22(20-8-15-7-19(15)37(20)23(14)25(39)32-16-5-6-17(30)18(31)9-16)24(38)26(40)33-29(11-42-12-29)21-10-36(35-34-21)13-43-27(41)28(2,3)4;1-10-18(20(32)22(34)28-23(8-35-9-23)17-7-26-30-29-17)16-5-11-4-15(11)31(16)19(10)21(33)27-12-2-3-13(24)14(25)6-12;1-7-14(16(23)18(25)26)13-5-8-4-12(8)22(13)15(7)17(24)21-9-2-3-10(19)11(20)6-9;1-14(2,3)13(20)23-11-19-7-12(17-18-19)16(8-22-9-16)10-24(21)15(4,5)6;1-10(2,3)9(16)18-7-15-4-8(13-14-15)11(12)5-17-6-11;1-5-9(6-12-7-9)10-13(11)8(2,3)4;;;;/h5-6,9-10,15,19H,7-8,11-13H2,1-4H3,(H,32,39)(H,33,40);2-3,6-7,11,15H,4-5,8-9H2,1H3,(H,27,33)(H,28,34)(H,26,29,30);2-3,6,8,12H,4-5H2,1H3,(H,21,24)(H,25,26);7H,8-11H2,1-6H3;4H,5-7,12H2,1-3H3;1,10H,6-7H2,2-4H3;3*1H4;1H/t15-,19-;11-,15-;8-,12-;24-;;13-;;;;/m1111.0..../s1.

What are the key properties of [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride?

[4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride has a molecular weight of 2337.00 g/mol, XLogP of 11.72, 28 rotatable bonds, 9 hydrogen bond donors, and 37 hydrogen bond acceptors.

Where does this data come from?

All data for [4-(3-aminooxetan-3-yl)triazol-1-yl]methyl 2,2-dimethylpropanoate;[4-[3-[[(R)-tert-butylsulfinyl]methyl]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetic acid;[4-[3-[[2-[(2R,4R)-9-[(3,4-difluorophenyl)carbamoyl]-8-methyl-1-azatricyclo[4.3.0.02,4]nona-6,8-dien-7-yl]-2-oxoacetyl]amino]oxetan-3-yl]triazol-1-yl]methyl 2,2-dimethylpropanoate;(2R,4R)-N-(3,4-difluorophenyl)-8-methyl-7-[2-oxo-2-[[3-(2H-triazol-4-yl)oxetan-3-yl]amino]acetyl]-1-azatricyclo[4.3.0.02,4]nona-6,8-diene-9-carboxamide;(S)-N-(3-ethynyloxetan-3-yl)-2-methylpropane-2-sulfinamide;methane;hydrochloride is sourced from PubChem (CID 161083464), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).