Tetrahedron: Asymmetry

Synthesis of tadalafil (Cialis) from l-tryptophan

S Xiao, XX Shi, J Xing, JJ Yan, SL Liu, WD Lu

Index: Xiao, Sen; Shi, Xiao-Xin; Xing, Jing; Yan, Jing-Jing; Liu, Shi-Ling; Lu, Wei-Dong Tetrahedron Asymmetry, 2009 , vol. 20, # 18 p. 2090 - 2096

Full Text: HTML

Citation Number: 10

Abstract

The first synthesis of tadalafil 1 (Cialis) from l-tryptophan is described. The title compound 1 was synthesized via seven steps from l-tryptophan methyl ester hydrochloride in 42.3% overall yield. Two characteristic steps involved in this synthesis are the base-catalyzed epimerization of the C-3 position of (1S, 3S)-1, 2, 3-trisubstituted-tetrahydro-β-carboline 3a and the acid-catalyzed epimerization of the C-1 position of (1S, 3R)-1, 3-disubstituted- ...