Formaldehyde → 6-Benzyloxy-4-methoxymethyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid isopropyl ester

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Reaction Steps

A solution is prepared from 3.8 g of 2-amino-3-(5-benzyloxyindol-3-yl)-4-methoxybutyric acid isopropyl ester (10 mmol) in 80 ml of xylene and added dropwise to a suspension of 360 mg of paraformaldehyde in 60 ml of xylene heated for 45 minutes to 100° C. The mixture is then refluxed for 2 hours on a water trap. After concentration, the residue is chromatographed over silica gel with methylene chloride:acetone=1:1 as the eluent, yielding 2.5 g of 6-benzyloxy-4-methoxymethyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid isopropyl ester (65% yield as an oil); or

Provenance & Evidence