dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride

C118H134Cl6F2I2K2N40O20 — CID 158826123

About dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride

dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride (PubChem CID 158826123) has the molecular formula C118H134Cl6F2I2K2N40O20 and a molecular weight of 3015.35 g/mol. Its IUPAC name is dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride.

Molecular Properties

• Compound Name: dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride
• PubChem CID: 158826123
• Molecular Formula: C118H134Cl6F2I2K2N40O20
• Molecular Weight: 3015.35 g/mol
• Exact Mass: 3010.62
• IUPAC Name: dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride
• SMILES: CC(=O)Cn1nc(-c2ncc[nH]2)c2cccnc21.CC(=O)Cn1nc(C(N)=NO)c2cccnc21.CC(C)(C)OC(=O)CCl.CC(C)(C)OC(=O)Cn1nc(C#N)c2cccnc21.CC(C)(C)OC(=O)Cn1nc(I)c2cccnc21.CCOc1cc(N2CCN(C(=O)Cn3nc(-c4ncc[nH]4)c4cccnc43)CC2)c(F)cc1Cl.CCOc1cc(N2CCNCC2)c(F)cc1Cl.Cl.Cl.Ic1[nH]nc2ncccc12.NO.O=C(O)Cn1nc(-c2ncc[nH]2)c2cccnc21.O=CCCl.O=CO[O-].[H-].[H]/N=C(\N)c1nn(CC(C)=O)c2ncccc12.[K+].[K+]
• InChI: InChI=1S/C23H23ClFN7O2.C13H14N4O2.C12H16ClFN2O.C12H14IN3O2.C12H11N5O.C11H9N5O2.C10H11N5O2.C10H11N5O.C6H11ClO2.C6H4IN3.C2H3ClO.CH2O3.2ClH.2K.H3NO.H/c1-2-34-19-13-18(17(25)12-16(19)24)30-8-10-31(11-9-30)20(33)14-32-23-15(4-3-5-28-23)21(29-32)22-26-6-7-27-22;1-13(2,3)19-11(18)8-17-12-9(5-4-6-15-12)10(7-14)16-17;1-2-17-12-8-11(10(14)7-9(12)13)16-5-3-15-4-6-16;1-12(2,3)18-9(17)7-16-11-8(10(13)15-16)5-4-6-14-11;1-8(18)7-17-12-9(3-2-4-15-12)10(16-17)11-13-5-6-14-11;17-8(18)6-16-11-7(2-1-3-14-11)9(15-16)10-12-4-5-13-10;1-6(16)5-15-10-7(3-2-4-12-10)8(13-15)9(11)14-17;1-6(16)5-15-10-7(3-2-4-13-10)8(14-15)9(11)12;1-6(2,3)9-5(8)4-7;7-5-4-2-1-3-8-6(4)10-9-5;3-1-2-4;2-1-4-3;;;;;1-2;/h3-7,12-13H,2,8-11,14H2,1H3,(H,26,27);4-6H,8H2,1-3H3;7-8,15H,2-6H2,1H3;4-6H,7H2,1-3H3;2-6H,7H2,1H3,(H,13,14);1-5H,6H2,(H,12,13)(H,17,18);2-4,17H,5H2,1H3,(H2,11,14);2-4H,5H2,1H3,(H3,11,12);4H2,1-3H3;1-3H,(H,8,9,10);2H,1H2;1,3H;2*1H;;;2H,1H2;/q;;;;;;;;;;;;;;2*+1;;-1/p-1
• InChIKey: KHPTYWFEUMYFLK-UHFFFAOYSA-M
• XLogP: 8.69
• TPSA: 812.22 Ų
• H-Bond Donors: 12
• H-Bond Acceptors: 52
• Rotatable Bonds: 28
• Heavy Atoms: 190
• Complexity: —

Lipinski Rule of Five

4 violations

Rule	Value
MW ≤ 500	3015.35
LogP ≤ 5	8.69
H-Bond Donors ≤ 5	12
H-Bond Acceptors ≤ 10	52

Computed Properties (RDKit)

• Structural Alerts: {'alert_name': '>_2_ester_groups', 'substructure': 'N/A'}, {'alert_name': 'aldehyde', 'substructure': 'N/A'}, {'alert_name': 'alkyl_halide', 'substructure': 'N/A'}, {'alert_name': 'imine_1', 'substructure': 'N/A'}, {'alert_name': 'imine_2', 'substructure': 'N/A'}

Frequently Asked Questions

What is the IUPAC name of dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride?

The IUPAC name of dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride (CID 158826123) is dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride.

What is the SMILES notation for dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride?

The canonical SMILES for dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride is CC(=O)Cn1nc(-c2ncc[nH]2)c2cccnc21.CC(=O)Cn1nc(C(N)=NO)c2cccnc21.CC(C)(C)OC(=O)CCl.CC(C)(C)OC(=O)Cn1nc(C#N)c2cccnc21.CC(C)(C)OC(=O)Cn1nc(I)c2cccnc21.CCOc1cc(N2CCN(C(=O)Cn3nc(-c4ncc[nH]4)c4cccnc43)CC2)c(F)cc1Cl.CCOc1cc(N2CCNCC2)c(F)cc1Cl.Cl.Cl.Ic1[nH]nc2ncccc12.NO.O=C(O)Cn1nc(-c2ncc[nH]2)c2cccnc21.O=CCCl.O=CO[O-].[H-].[H]/N=C(\N)c1nn(CC(C)=O)c2ncccc12.[K+].[K+].

What is the InChIKey of dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride?

The InChIKey is KHPTYWFEUMYFLK-UHFFFAOYSA-M. The full InChI is InChI=1S/C23H23ClFN7O2.C13H14N4O2.C12H16ClFN2O.C12H14IN3O2.C12H11N5O.C11H9N5O2.C10H11N5O2.C10H11N5O.C6H11ClO2.C6H4IN3.C2H3ClO.CH2O3.2ClH.2K.H3NO.H/c1-2-34-19-13-18(17(25)12-16(19)24)30-8-10-31(11-9-30)20(33)14-32-23-15(4-3-5-28-23)21(29-32)22-26-6-7-27-22;1-13(2,3)19-11(18)8-17-12-9(5-4-6-15-12)10(7-14)16-17;1-2-17-12-8-11(10(14)7-9(12)13)16-5-3-15-4-6-16;1-12(2,3)18-9(17)7-16-11-8(10(13)15-16)5-4-6-14-11;1-8(18)7-17-12-9(3-2-4-15-12)10(16-17)11-13-5-6-14-11;17-8(18)6-16-11-7(2-1-3-14-11)9(15-16)10-12-4-5-13-10;1-6(16)5-15-10-7(3-2-4-12-10)8(13-15)9(11)14-17;1-6(16)5-15-10-7(3-2-4-13-10)8(14-15)9(11)12;1-6(2,3)9-5(8)4-7;7-5-4-2-1-3-8-6(4)10-9-5;3-1-2-4;2-1-4-3;;;;;1-2;/h3-7,12-13H,2,8-11,14H2,1H3,(H,26,27);4-6H,8H2,1-3H3;7-8,15H,2-6H2,1H3;4-6H,7H2,1-3H3;2-6H,7H2,1H3,(H,13,14);1-5H,6H2,(H,12,13)(H,17,18);2-4,17H,5H2,1H3,(H2,11,14);2-4H,5H2,1H3,(H3,11,12);4H2,1-3H3;1-3H,(H,8,9,10);2H,1H2;1,3H;2*1H;;;2H,1H2;/q;;;;;;;;;;;;;;2*+1;;-1/p-1.

What are the key properties of dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride?

dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride has a molecular weight of 3015.35 g/mol, XLogP of 8.69, 28 rotatable bonds, 12 hydrogen bond donors, and 52 hydrogen bond acceptors.

Where does this data come from?

All data for dipotassium;tert-butyl 2-chloroacetate;tert-butyl 2-(3-cyanopyrazolo[3,4-b]pyridin-1-yl)acetate;tert-butyl 2-(3-iodopyrazolo[5,4-b]pyridin-1-yl)acetate;2-chloroacetaldehyde;1-(4-chloro-5-ethoxy-2-fluorophenyl)piperazine;1-[4-(4-chloro-5-ethoxy-2-fluorophenyl)piperazin-1-yl]-2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]ethanone;hydride;hydroxylamine;N'-hydroxy-1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;2-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]acetic acid;1-[3-(1H-imidazol-2-yl)pyrazolo[5,4-b]pyridin-1-yl]propan-2-one;3-iodo-2H-pyrazolo[3,4-b]pyridine;oxido formate;1-(2-oxopropyl)pyrazolo[5,4-b]pyridine-3-carboximidamide;dihydrochloride is sourced from PubChem (CID 158826123), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).