497182-99-7

Upstream product

• 100-39-0 benzyl bromide 
• 171596-42-2 (1S,3R)-1-(3,4-methylenedioxyphenyl)-2,3,4,9-tetrahidro-9H-pyrido[3,4-b]indole-3-carboxylic acid methyl ester 
• 4299-70-1 D-Tryptophan methyl ester 
• 1453863-96-1 (1S,3S)-methyl 1-(benzo[d][1,3]dioxol-5-yl)-2-benzyl-1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole-3-carboxylate 
• 120-57-0 piperonal 

Downstream Products

• 171596-42-2 (1S,3R)-1-(3,4-methylenedioxyphenyl)-2,3,4,9-tetrahidro-9H-pyrido[3,4-b]indole-3-carboxylic acid methyl ester 

Relevant academic research and scientific papers

Highly stereoselective transformation of (1S,3S)-cis-1,3-disubstituted tetrahydro-β-carbolines into (1S,3R)-trans-1,3-disubstituted tetrahydro-β-carbolines: An improved asymmetric synthesis of tadalafil from l-tryptophan

An efficient and general method for the highly stereoselective transformation of (1S,3S)-cis-1,3-disubstituted 1,2,3,4-tetrahydro-β- carbolines (THBCs) into (1S,3R)-trans-1,3-disubstituted THBCs is described. The method contains the following three steps: the enantiomerically pure (1S,3S)-cis-1,3-disubstituted THBCs 1 were first converted into (1S,3S)-cis-1,2,3-trisubstituted THBCs 2 by N-1-naphthylmethylation/benzylation; (1S,3S)-cis-1,2,3-trisubstituted THBCs2 were then converted into (1S,3R)-trans-1,2,3-trisubstituted THBCs 3 in high yields and with high stereoselectivities via a base-catalyzed epimerization at C-3; (1S,3R)-trans-1,2,3-trisubstituted THBCs 3 were subsequently converted into (1S,3R)-trans-1,3-disubstituted THBCs 4 after reductive removal of the 1-naphthylmethyl/benzyl group. In addition, as an application of this method, an improved and highly stereoselective synthesis of the PDE5 inhibitor tadalafil (Cialis) starting from natural and less expensive l-tryptophan was developed.

Potassium superoxide as an alternative reagent for Winterfeldt oxidation of beta-carbolines.

Potassium superoxide was examined as an alternative oxidation reagent for the Winterfeldt reaction. KO(2) was found to be superior to the original Winterfeldt protocol for base-sensitive substrates. [reaction--see text]