Quinuclidine
Chemical compound
From Wikipedia, the free encyclopedia
Quinuclidine is an organic compound with the formula 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.
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| Names | |||
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| Preferred IUPAC name
1-Azabicyclo[2.2.2]octane[2] | |||
| Other names
Quinuclidine[2] | |||
| Identifiers | |||
3D model (JSmol) |
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| 103111 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| ECHA InfoCard | 100.002.625 | ||
| EC Number |
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| 26726 | |||
PubChem CID |
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| UNII | |||
CompTox Dashboard (EPA) |
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| Properties | |||
| C7H13N | |||
| Molar mass | 111.188 g·mol−1 | ||
| Density | 0.97 g/cm3 | ||
| Melting point | 157 to 160 °C (315 to 320 °F; 430 to 433 K) | ||
| Boiling point | 149.5 °C (301.1 °F; 422.6 K) at 760 mmHg | ||
| Acidity (pKa) | 11.0 (conjugate acid) | ||
| Hazards | |||
| GHS labelling:[3] | |||
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| Danger | |||
| H301, H310, H315, H318 | |||
| P262, P264, P264+P265, P270, P280, P301+P316, P302+P352, P305+P354+P338, P316, P317, P321, P330, P332+P317, P361+P364, P362+P364, P405, P501 | |||
| Flash point | 36.5 °C (97.7 °F; 309.6 K) | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.[4]
Quinuclidine is a relatively strong organic base with pKa of the conjugate acid of 11.3.[5] 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).[6]
It forms adducts with a variety of Lewis acids. Because of its compact structure, quinuclidine binds to trimethylborane more tightly than does triethylamine.[7]
Derivatives and analogues
Quinine 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.[7] Aceclidine, a simple quinuclidine derivative, is a drug used for treatment of glaucoma.