7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine

C231H137N5O9 — CID 157297218

About 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine

7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine (PubChem CID 157297218) has the molecular formula C231H137N5O9 and a molecular weight of 3126.66 g/mol. Its IUPAC name is 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine.

Molecular Properties

• Compound Name: 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine
• PubChem CID: 157297218
• Molecular Formula: C231H137N5O9
• Molecular Weight: 3126.66 g/mol
• Exact Mass: 3124.04
• IUPAC Name: 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine
• SMILES: CC1(C)c2ccccc2-c2cc(-c3ccc4c(c3)C(c3ccc5ccccc5c3)(c3ccc5ccccc5c3)c3cc(-c5ccc6c(c5)-c5ccccc5C6(C)C)c5oc6ccccc6c5c3-4)ccc21.c1ccc2c(c1)-c1c(ccc3c1CCN3)C21c2ccc3ccccc3c2-c2c1cc(-c1ccc3c(c1)[nH]c1ccccc13)c1c2oc2ccccc21.c1ccc2c(c1)-c1c(ccc3c1oc1ccccc13)C21c2cc(-c3ccc4oc5ccncc5c4c3)ccc2-c2c1cc(-c1ccc3oc4ccccc4c3c1)c1oc3ccccc3c21.c1ccc2c(c1)-c1ccccc1C21c2cc(-c3ccc4c(c3)oc3ncccc34)ccc2-c2c1cc(-c1ccc3c(c1)oc1ncccc13)c1oc3ccccc3c21
• InChI: InChI=1S/C69H48O.C60H31NO4.C53H28N2O3.C49H30N2O/c1-67(2)57-22-12-9-19-50(57)55-37-45(28-33-59(55)67)46-27-32-52-61(39-46)69(48-30-25-41-15-5-7-17-43(41)35-48,49-31-26-42-16-6-8-18-44(42)36-49)62-40-54(66-65(64(52)62)53-21-11-14-24-63(53)70-66)47-29-34-60-56(38-47)51-20-10-13-23-58(51)68(60,3)4;1-5-13-45-38(11-1)56-46(22-21-37-35-9-2-7-15-50(35)64-58(37)56)60(45)47-29-33(32-18-23-53-43(27-32)44-31-61-26-25-54(44)63-53)17-20-39(47)55-48(60)30-41(59-57(55)40-12-4-8-16-51(40)65-59)34-19-24-52-42(28-34)36-10-3-6-14-49(36)62-52;1-4-14-41-32(9-1)33-10-2-5-15-42(33)53(41)43-25-29(30-17-20-34-36-12-7-23-54-51(36)57-46(34)26-30)18-22-38(43)48-44(53)28-40(50-49(48)39-11-3-6-16-45(39)56-50)31-19-21-35-37-13-8-24-55-52(37)58-47(35)27-31;1-2-10-29-27(9-1)18-20-38-46(29)47-39(49(38)36-14-6-3-12-32(36)44-33-23-24-50-40(33)22-21-37(44)49)26-35(45-34-13-5-8-16-43(34)52-48(45)47)28-17-19-31-30-11-4-7-15-41(30)51-42(31)25-28/h5-40H,1-4H3;1-31H;1-28H;1-22,25-26,50-51H,23-24H2
• InChIKey: BBMDYLRRGKGDHE-UHFFFAOYSA-N
• XLogP: 60.76
• TPSA: 184.75 Ų
• H-Bond Donors: 2
• H-Bond Acceptors: 13
• Rotatable Bonds: 9
• Heavy Atoms: 245
• Complexity: —

Lipinski Rule of Five

3 violations

Rule	Value
MW ≤ 500	3126.66
LogP ≤ 5	60.76
H-Bond Donors ≤ 5	2
H-Bond Acceptors ≤ 10	13

Frequently Asked Questions

What is the IUPAC name of 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine?

The IUPAC name of 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine (CID 157297218) is 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine.

What is the SMILES notation for 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine?

The canonical SMILES for 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine is CC1(C)c2ccccc2-c2cc(-c3ccc4c(c3)C(c3ccc5ccccc5c3)(c3ccc5ccccc5c3)c3cc(-c5ccc6c(c5)-c5ccccc5C6(C)C)c5oc6ccccc6c5c3-4)ccc21.c1ccc2c(c1)-c1c(ccc3c1CCN3)C21c2ccc3ccccc3c2-c2c1cc(-c1ccc3c(c1)[nH]c1ccccc13)c1c2oc2ccccc21.c1ccc2c(c1)-c1c(ccc3c1oc1ccccc13)C21c2cc(-c3ccc4oc5ccncc5c4c3)ccc2-c2c1cc(-c1ccc3oc4ccccc4c3c1)c1oc3ccccc3c21.c1ccc2c(c1)-c1ccccc1C21c2cc(-c3ccc4c(c3)oc3ncccc34)ccc2-c2c1cc(-c1ccc3c(c1)oc1ncccc13)c1oc3ccccc3c21.

What is the InChIKey of 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine?

The InChIKey is BBMDYLRRGKGDHE-UHFFFAOYSA-N. The full InChI is InChI=1S/C69H48O.C60H31NO4.C53H28N2O3.C49H30N2O/c1-67(2)57-22-12-9-19-50(57)55-37-45(28-33-59(55)67)46-27-32-52-61(39-46)69(48-30-25-41-15-5-7-17-43(41)35-48,49-31-26-42-16-6-8-18-44(42)36-49)62-40-54(66-65(64(52)62)53-21-11-14-24-63(53)70-66)47-29-34-60-56(38-47)51-20-10-13-23-58(51)68(60,3)4;1-5-13-45-38(11-1)56-46(22-21-37-35-9-2-7-15-50(35)64-58(37)56)60(45)47-29-33(32-18-23-53-43(27-32)44-31-61-26-25-54(44)63-53)17-20-39(47)55-48(60)30-41(59-57(55)40-12-4-8-16-51(40)65-59)34-19-24-52-42(28-34)36-10-3-6-14-49(36)62-52;1-4-14-41-32(9-1)33-10-2-5-15-42(33)53(41)43-25-29(30-17-20-34-36-12-7-23-54-51(36)57-46(34)26-30)18-22-38(43)48-44(53)28-40(50-49(48)39-11-3-6-16-45(39)56-50)31-19-21-35-37-13-8-24-55-52(37)58-47(35)27-31;1-2-10-29-27(9-1)18-20-38-46(29)47-39(49(38)36-14-6-3-12-32(36)44-33-23-24-50-40(33)22-21-37(44)49)26-35(45-34-13-5-8-16-43(34)52-48(45)47)28-17-19-31-30-11-4-7-15-41(30)51-42(31)25-28/h5-40H,1-4H3;1-31H;1-28H;1-22,25-26,50-51H,23-24H2.

What are the key properties of 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine?

7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine has a molecular weight of 3126.66 g/mol, XLogP of 60.76, 9 rotatable bonds, 2 hydrogen bond donors, and 13 hydrogen bond acceptors.

Where does this data come from?

All data for 7-[11-([1]benzofuro[2,3-b]pyridin-7-yl)spiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,9'-fluorene]-17-yl]-[1]benzofuro[2,3-b]pyridine;11,17-bis(9,9-dimethylfluoren-3-yl)-14,14-dinaphthalen-2-yl-9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene;15'-(9H-carbazol-2-yl)spiro[2,3-dihydro-1H-indeno[1,2-e]indole-6,12'-23-oxahexacyclo[11.11.0.02,11.03,8.016,24.017,22]tetracosa-1(13),2(11),3,5,7,9,14,16(24),17,19,21-undecaene];8-(11-dibenzofuran-2-ylspiro[9-oxapentacyclo[11.7.0.02,10.03,8.015,20]icosa-1(13),2(10),3,5,7,11,15(20),16,18-nonaene-14,7'-fluoreno[4,3-b][1]benzofuran]-17-yl)-[1]benzofuro[3,2-c]pyridine is sourced from PubChem (CID 157297218), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).