5222. Isoquinoline

Nomenclature

CAS number: 119-65-3
2-Benzazine; benzo[c]pyridine.
C9H7N; mol wt 129.16.
C 83.69%, H 5.46%, N 10.84%.

Description and references

Occurs in coal tar: Hoogewerff, van Dorp, Rec. Trav. Chim. 4, 125, 285 (1885); Weissgerber, Ber. 47, 3175 (1914); Harris, Pope, J. Chem. Soc. 121, 1029 (1922). Modern isoln processes: H. J. V. Winkler, Der Steinkohlenteer und seine Aufarbeitung (Essen, 1951). Isoln by a freeze-out method: Kjellman, US 2483420 (1946 to Koppers). Purification: Freiser, Glowacki, J. Am. Chem. Soc. 71, 514 (1949). Synthesis: D. L. Boger et al., Tetrahedron 37, 3977 (1981). Toxicity data: Smyth et al., Arch. Ind. Hyg. Occup. Med. 4, 119 (1951). Comprehensive survey of isoquinoline alkaloids: Gensler, Heterocyclic Compounds vol. 4, R. C. Elderfield, Ed. (Wiley, New York, 1952) pp 344-490; T. Kametani, Total Synthesis of Natural Products vol. 3, J. ApSimon, Ed. (Wiley, New York, 1977) pp 1-272.

Chemical structure

Properties

Liquid. Pungent odor resembling that of a mixture of anise oil and benzaldehyde. Hygroscopic platelets when solid. d430 1.09101; d480 1.05143. mp 26.48°. nD30 1.62078. Viscosity (cP): 3.2528 (30°); 1.0230 (100°); 0.4223 (200°). bp743 242.2°; bp760 243.25°. Dipole moment: 2.49. More basic than quinoline, pKa (25°): 8.60. Almost insol in water. Miscible with many organic solvents. Sol in dil acids. LD50 orally in rats: 360 mg/kg (Smyth).

Derivative

Sulfate.
C9H7N.H2SO4; mol wt 227.24.
C 47.57%, H 3.99%, N 6.16%, S 14.11%, O 28.16%.

Properties

Crystals, mp 209-209.5°. Sol in water.

Use

Synthesis of dyes, insecticides, antimalarials, rubber accelerators.