Quinuclidine
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 464379026
| Reference =[https://www.sigmaaldrich.com/US/en/product/sial/22709 Quinuclidine] {{webarchive |url=https://web.archive.org/web/20071015200029/http://www.sigmaaldrich.com/catalog/search/ProductDetail?ProdNo=22709&Brand=FLUKA |date=October 15, 2007 }} at Sigma-Aldrich
| ImageFileL1_Ref = {{chemboximage|correct|??}}
| ImageFileL1 = Quinuclidine.svg
| ImageSizeL1 = 140px
| ImageNameL1 = Skeletal formula of quinuclidine
| ImageFileR1 = Quinuclidine 3D.png
| ImageSizeR1 = 140px
| ImageNameR1 = Ball-and-stick model of quinuclidine
| PIN = 1-Azabicyclo[2.2.2]octane{{cite book | title = Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = The Royal Society of Chemistry | date = 2014 | location = Cambridge | page = 169 | doi = 10.1039/9781849733069-FP001 | isbn = 978-0-85404-182-4 | quote = The name quinuclidine is retained for general nomenclature only (see Table 2.6).}}
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 100-76-5
| Beilstein = 103111
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 38420
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 1209648
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 7246
| EC_number = 202-887-1
| Gmelin = 26726
| PubChem = 7527
| UNII_Ref = {{fdacite|changed|FDA}}
| UNII = XFX99FC5VI
| InChI = 1/C7H13N/c1-4-8-5-2-7(1)3-6-8/h7H,1-6H2
| InChIKey = SBYHFKPVCBCYGV-UHFFFAOYAA
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C7H13N/c1-4-8-5-2-7(1)3-6-8/h7H,1-6H2
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = SBYHFKPVCBCYGV-UHFFFAOYSA-N
| SMILES = N12CCC(CC1)CC2
}}
|Section2={{Chembox Properties
| C=7
| H=13
| N=1
| Appearance =
| Density = 0.97 g/cm3
| MeltingPtC = 157 to 160
| MeltingPt_notes =
| BoilingPtC = 149.5
| BoilingPt_notes = at 760 mmHg
| Solubility =
| pKa = 11.0 (conjugate acid)
}}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS05}}{{GHS06}}{{GHS07}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|301|310|315|318}}
| PPhrases = {{P-phrases|262|264|264+265|270|280|301+316|302+352|305+354+338|316|317|321|330|332+317|361+364|362+364|405|501}}
| MainHazards =
| FlashPtC = 36.5
| AutoignitionPtC =
}}
}}
Quinuclidine is an organic compound with the formula {{chem2|HC(C2H4)3N}}. It is a bicyclic amine that can be viewed as a tied back version of triethylamine. It is a colorless solid. It is used as a reagent (base) and catalyst. It can be prepared by reduction of quinuclidone.
Structure and chemical properties
Regarding its structure, quinuclidine is unusual in that the methylene hydrogen atoms are eclipsed within each of the three ethylene linkages. Furthermore, the cyclohexane rings, of which there are three, adopt the boat conformations, not the usual chair conformations.{{cite journal |doi=10.1021/jo00384a013 |title=Charge-Rransfer Interactions of Amines with Tetrahalomethanes. X-Ray Crystal Structures of the Donor-Acceptor Complexes of Quinuclidine and Diazabicyclo [2.2.2]Octane with Carbon Tetrabromide |year=1987 |last1=Blackstock |first1=S. C. |last2=Lorand |first2=J. P. |last3=Kochi |first3=J. K. |journal=The Journal of Organic Chemistry |volume=52 |issue=8 |pages=1451–1460 }}
Quinuclidine is a relatively strong organic base with pKa of the conjugate acid of 11.3.{{cite journal |title=Azatriquinanes: Synthesis, Structure, and Reactivity |author1=Hext, N. M. |author2=Hansen, J. |author3=Blake, A. J. |author4=Hibbs, D. E. |author5=Hursthouse, M. B. |author6=Shishkin, O. V. |author7=Mascal, M. |journal=J. Org. Chem. |year=1998 |volume=63 |issue=17 |pages=6016–6020 |doi=10.1021/jo980788s |pmid=11672206}} The basicity of other quinuclidines have been evaluated:
3-hydroxy- quinuclidine (9.9), 3-acetoxyquinuclidine (9.3), 3-chloroquinuclidine (8.9), DABCO (8.7), and 3-quinuclidone (7.2).{{cite journal |doi=10.1021/jo026671s |title=Correlation between pKa and Reactivity of Quinuclidine-Based Catalysts in the Baylis−Hillman Reaction: Discovery of Quinuclidine as Optimum Catalyst Leading to Substantial Enhancement of Scope |year=2003 |last1=Aggarwal |first1=Varinder K. |last2=Emme |first2=Ingo |last3=Fulford |first3=Sarah Y. |journal=The Journal of Organic Chemistry |volume=68 |issue=3 |pages=692–700 |pmid=12558387 }}
It forms adducts with a variety of Lewis acids. Because of its compact structure, quinuclidine binds to trimethylborane more tightly than does triethylamine.{{cite journal| doi=10.1002/jhet.5570430601 | title=Chemistry of quinuclidines as nitrogen bicyclic bridged-ring structures | year=2006 | last1=Hamama | first1=Wafaa S. | last2=El-Magid | first2=Osama. M. Abd | last3=Zoorob | first3=Hanafi H. | journal=Journal of Heterocyclic Chemistry | volume=43 | issue=6 | pages=1397–1420 | doi-access=free }}
Derivatives and analogues
:image:Quinine.svg is a quinuclidine derivative.]]
Quinuclidine is structurally related to DABCO, in which the other bridgehead is also nitrogen, and to tropane, which has a slightly different carbon frame. Due to this similarity, as with tropane, certain quinuclidines such as solifenacin, aclidinium bromide and 3-Quinuclidinyl benzilate possess antimuscarinic properties.
Cinchona alkaloids, e.g. quinine, feature quinuclidine substituents. Aceclidine, a simple quinuclidine derivative, is a drug used for treatment of glaucoma.
Isoquinuclidines
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