Quinuclidine

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.

Quinuclidine^[1]

Skeletal formula of quinuclidine Ball-and-stick model of quinuclidine
Names
Preferred IUPAC name 1-Azabicyclo[2.2.2]octane[2]
Other names Quinuclidine[2]
Identifiers
CAS Number	100-76-5 Y
3D model (JSmol)	Interactive image
Beilstein Reference	103111
ChEBI	CHEBI:38420 Y
ChEMBL	ChEMBL1209648 Y
ChemSpider	7246 Y
ECHA InfoCard	100.002.625
EC Number	202-887-1
Gmelin Reference	26726
PubChem CID	7527
UNII	XFX99FC5VI N
CompTox Dashboard (EPA)	DTXSID2057607
InChI InChI=1S/C7H13N/c1-4-8-5-2-7(1)3-6-8/h7H,1-6H2 Y Key: SBYHFKPVCBCYGV-UHFFFAOYSA-N Y InChI=1/C7H13N/c1-4-8-5-2-7(1)3-6-8/h7H,1-6H2 Key: SBYHFKPVCBCYGV-UHFFFAOYAA
SMILES N12CCC(CC1)CC2
Properties
Chemical formula	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]
Pictograms
Signal word	Danger
Hazard statements	H301, H310, H315, H318
Precautionary statements	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). N verify (what is YN ?) Infobox references

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 pK_a 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.

Isoquinuclidines