101533-87-3

Upstream product

• 4299-70-1 L-tryptophan methyl ester 
• 101533-84-0 (1R,3S)-3-methoxycarbonyl-1-methoxycarbonylmethyl-1,2,3,4-tetrahydro-9H-pyrido<3,4-b>indole 
• 100-39-0 benzyl bromide 
• 21469-60-3 (S)-N^α-benzyl-Nⁱⁿ-methyltryptophan methyl ester 
• 63229-68-5 methyl N-benzyl-L-tryptophanate 
• 101533-85-1 (1R,3S)-2-benzyl-3-methoxycarbonyl-1-methylcarboxy-methyl-1,2,3,4-tetrahydro-9H-pyrido<3,4-b> indole 
• 74-88-4 methyl iodide 
• 922-67-8 propynoic acid methyl ester 

Relevant academic research and scientific papers

APPLICATION OF A MODIFIED PICTET-SPENGLER REACTION TO THE SYNTHESIS OF OPTICALLY ACTIVE TETRAHYDRO-β-CARBOLINES, KEY INTERMEDIATES IN THE PREPARATION OF MANY INDOLE ALKALOIDS

A recent modification of the Pictet-Spengler reaction has been applied to the synthesis of optically active tetrahydro-β-carbolines.The method was initially investigated by treating various Nin,Nα-substituted tryptophan methyl esters (10) with methyl propynoate or dimethyl butynedioate; cyclisation of the resulting enamines (13) was achieved by the addition of trifluoroacetic acid, to give the desired tetrahydro-β-carbolines as mixtures of diastereoisomers (11) and (12).Single crystal X-ray structure determinations were carried out on two of the isolated diastereoisomers (12b) and (11e); chemical modification of these compounds allowed an unambiguous assignment of stereochemistry to all of the products from the modified Pictet-Spengler reaction.It was thereby ascertained that Nin-methylation and/or Nα-benzylation of the tryptophan methyl esters led to an increase in the proportion of trans products after condensation/cyclisation with methyl propynoate.This observation was applied to the preparation of the cis-cyano ester (3), which was required as a key intermediate in the synthesis of alkaloids of the ajmaline group.

THE USE OF 13C N.M.R. IN THE DETERMINATION OF STEREOCHEMISTRY OF 1,2,3-TRISUBSTITUTED TETRAHYDRO-β-CARBOLINES

The chemical shift of the benzylic carbon of N(2)-benzyl-cis-1,3-disubstituted 1,2,3,4-tetrahydro-β-carbolines is downfield of the corresponding peak of the trans-isomer, and should be valuable, therefore, in the assignment of stereochemistry to these systems.

The Formation of Optically Active 1,3-Disubstituted and 1,1,3-Trisubstituted Tetrahydro-β-carbolines using a Modified Pictet-Spengler Reaction

Optically active 1,3-disubstituted and 1,1,3-trisubstituted 1,2,3,4-tetrahydro-β-carbolines were formed by the reaction of various Nα,Nin-substituted (S)-tryptophan methyl esters with methyl propynoate or dimethyl butynedioate respectively; the stereoselectivity of the reactions is reported.