Tetrahydroisoquinoline

This article is about the simple heterocyclic amine. For the selective MC4 agonist, see THIQ.
Tetrahydroisoquinoline
Names
Preferred IUPAC name
1,2,3,4-Tetrahydroisoquinoline
Identifiers
3D model (JSmol)
Abbreviations TIQ, THIQ
ChEMBL
ChemSpider
ECHA InfoCard 100.001.864
EC Number
  • 202-050-0
PubChem CID
RTECS number
  • NX4900000
UNII
  • InChI=1S/C9H11N/c1-2-4-9-7-10-6-5-8(9)3-1/h1-4,10H,5-7H2 check
    Key: UWYZHKAOTLEWKK-UHFFFAOYSA-N check
  • InChI=1/C9H11N/c1-2-4-9-7-10-6-5-8(9)3-1/h1-4,10H,5-7H2
    Key: UWYZHKAOTLEWKK-UHFFFAOYAB
  • c1ccc2c(c1)CCNC2
Properties
C9H11N
Molar mass 133.19 g/mol
Appearance Deep yellow liquid
Density 1.05 g/mL
Melting point −30 °C (−22 °F; 243 K)
Boiling point 235 to 239 °C (455 to 462 °F; 508 to 512 K)
Hazards
GHS labelling:
GHS05: CorrosiveGHS06: ToxicGHS08: Health hazard
Danger
H301, H310, H314, H332, H371, H412
P260, P261, P262, P264, P270, P271, P273, P280, P301+P310, P301+P330+P331, P302+P350, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P309+P311, P310, P312, P322, P330, P332+P313, P337+P313, P361, P362, P363, P403+P233, P405, P501
Flash point 99 °C (210 °F; 372 K) (closed cup)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
check verify (what is check☒ ?)
Infobox references

Tetrahydroisoquinoline (TIQ or THIQ) is an organic compound with the chemical formula C9H11N. Classified as a secondary amine, it is derived from isoquinoline by hydrogenation. It is a colorless viscous liquid that is miscible with most organic solvents. The tetrahydroisoquinoline skeleton is encountered in a number of bioactive compounds and drugs.

Reactions

As a secondary amine, tetrahydroisoquinoline has weakly basic properties and forms salts with strong acids. It can be dehydrogenated to give isoquinoline and hydrogenated to decahydroisoquinoline. Like other secondary amines, tetrahydroisoquinoline can be oxidized to the corresponding nitrone using hydrogen peroxide, catalyzed by selenium dioxide.

Toxicology

Tetrahydroisoquinoline derivatives may be formed in the body as metabolites of some drugs, and this was once thought to be involved in the development of alcoholism. This theory has now been discredited and is no longer generally accepted by the scientific community, but endogenous production of neurotoxic tetrahydroisoquinoline derivatives such as norsalsolinol continue to be investigated as possible causes for some conditions such as Parkinson's disease.

Tetrahydroisoquinolines

The tetrahydroisoquinoline skeleton is present in a number of drugs, such as tubocurarine, one of the quaternary ammonium muscle relaxants. Drugs based on 4-substituted tetrahydroisoquinolines include nomifensine and diclofensine. They can be prepared by N-alkylation of benzyl amines with haloacetophenones. Naturally occurring tetrahydroisoquinolines include cherylline and latifine.

Esproquin, which shows hypotensive activity by virtue of its α-adrenergic blocking properties, is made from THIQ.