4190. Flupirtine

Nomenclature

CAS number: 56995-20-1
[2-Amino-6-[[(4-fluorophenyl)methyl]amino]-3-pyridinyl]carbamic acid ethyl ester; 2-amino-6-[(p-fluorobenzyl)amino]-3-pyridinecarbamic acid ethyl ester; D-9998.
C15H17FN4O2; mol wt 304.32.
C 59.20%, H 5.63%, F 6.24%, N 18.41%, O 10.51%.

Description and references

Substituted pyridine with central analgesic properties. Prepn: K. Thiele, W. von Bebenburg, ZA 6902364 (1970 to Degussa); W. von Bebenburg et al., Chem. Ztg. 103, 387 (1979); eidem, ibid. 105, 217 (1981). Prepn of maleate: W. von Bebenburg, S. Pauluhn, BE 890331; eidem, US 4481205 (1980, 1984 both to Degussa). Comparison of pharmacology with other analgesics: V. Jakovlev et al., Arzneim.-Forsch. 35, 30 (1985). Pharmacokinetic studies: K. Obermeier et al., ibid. 60. Effect on driving ability: B. Biehl, ibid. 77. Clinical trials in treatment of cancer pain: W. Scheef, D. Wolf-Gruber, ibid. 75. Efficacy in treatment of pain after hysterectomy: R. A. Moore et al., Br. J. Anaesth. 55, 429 (1983). Symposium on pharmacology and clinical efficacy: Postgrad. Med. J. 63, Suppl. 3, 1-113 (1987).

Chemical structure

Properties

Crystals from isopropanol, mp 115-116°. 5% ethanol soln is colorless, turns green on exposure to air for 20 hours. LD50 orally in mice, rats: 617, 1660 mg/kg (Jakovlev).

Derivative

Hydrochloride.
C15H17FN4O2.HCl; mol wt 340.78.
C 52.87%, H 5.32%, F 5.57%, N 16.44%, O 9.39%, Cl 10.40%.

Properties

Crystals from water, mp 214-215°. When prepd industrially contains intensely blue by-product.

Derivative

Maleate.

Nomenclature

CAS number: 75507-68-5
Katadolon (AWD).
C15H17FN4O2.C4H4O4; mol wt 420.39.
C 54.28%, H 5.04%, F 4.52%, N 13.33%, O 22.84%.

Properties

Colorless crystals from isopropanol, mp 175.5-176°. Formed as mixture of two crystalline forms A and B; mixtures containing 60-90% A are preferred.

Therapeutic Category

Analgesic.

Keywords

Analgesic; Non-opioids