Quinaldine

Quinaldine or 2-methylquinoline is an organic compound with the formula CH₃C₉H₆N. It is one of the methyl derivatives of the heterocyclic compound quinoline. It is bioactive and is used in the preparation of various dyes. It is a colorless oil but commercial samples can appear colored.^[1]

Quinaldine

Names
Preferred IUPAC name 2-Methylquinoline
Other names Quinaldine, α-methylquinoline, chinaldine, khinaldin
Identifiers
CAS Number	91-63-4 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:132813
ChEMBL	ChEMBL194931 Y
ChemSpider	13870160 Y
ECHA InfoCard	100.001.896
EC Number	202-085-1
PubChem CID	7060
UNII	DVG30M0M87 Y
CompTox Dashboard (EPA)	DTXSID3040271
InChI InChI=1S/C10H9N/c1-8-6-7-9-4-2-3-5-10(9)11-8/h2-7H,1H3 Y Key: SMUQFGGVLNAIOZ-UHFFFAOYSA-N Y InChI=1/C10H9N/c1-8-6-7-9-4-2-3-5-10(9)11-8/h2-7H,1H3
SMILES Cc1nc2ccccc2cc1
Properties
Chemical formula	C10H9N
Molar mass	143.19 g/mol
Appearance	colorless oil
Density	1.058 g/cm3
Melting point	−2 °C (28 °F; 271 K)
Boiling point	248 °C (478 °F; 521 K)
Solubility in water	Insoluble
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H312, H319
Precautionary statements	P264, P270, P280, P301+P312, P302+P352, P305+P351+P338, P312, P322, P330, P337+P313, P363, P501
NFPA 704 (fire diamond)	2 2 0
Flash point	79 °C (174 °F; 352 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

Production and reactions

Quinaldine is recovered from coal tar. It can be prepared from aniline and paraldehyde via Skraup synthesis or from aniline and crotonaldehyde via Doebner-von Miller variation of the Skraup reaction.^[1]

Hydrogenation of quinaldine gives 2-methyltetrahydroquinoline. This reduction can be conducted enantioselectively.^[2]

Properties

Quinaldine has critical point at 787 K and 4.9 MPa and its refractive index is 1.8116.^{[citation needed]}

Uses

Quinaldine is used in manufacturing anti-malaria drugs, dyes and food colorants (e.g., Quinoline Yellows, pinacyanol). It is the precursor to the pH indicator Quinaldine Red.

Quinoline Yellow is a popular dye derived from quinaldine.

Quinaldine Red, a pH indicating dye.

Quinaldine sulfate is an anaesthetic used in fish transportation.^[3] In some Caribbean islands it is used to facilitate the collection of tropical fish from reefs.