Tanabe Seiyaku Company, Limited

Goro Hayashi

Mikio Takeda

Hirozumi Inoue

Seiichi Nurimoto

A compound of the formula: ##SPC1## Wherein R.sup.1 is hydrogen, phenyl, alkyl of one to five carbon atoms, cycloalkyl of three to four carbon atoms, or alkyl of one to five carbon atoms having a substituent selected from the group consisting of phenyl, benzoyl and 4-fluorobenzoyl, R.sup.2 is hydrogen or alkyl of one to three carbon atoms, and R.sup.3 is hydrogen, alkanoyl of two to six carbon atoms, benzoyl or nicotinoyl, is disclosed. Several methods for preparing the compound (I) is also disclosed. The compound (I) and a pharmaceutically acceptable acid addition salt thereof are useful as analgesic agents.

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Toyonaka, Japan

Goro Hayashi