ISSN:
0170-2041
Keywords:
β-Carboline derivatives
;
Pyrido[3,4-b]indole derivatives
;
Indolo[2,3-a]quinolizine derivatives
;
Alkaloids
;
Pictet-Spengler reaction
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
L-Tryptophan methyl ester reacts with 1,1,3,3-tetramethoxypropane to give methyl carbolinecarboxylate 2 as a 1:2 mixture of the (1R,3S) and (1S,3S) stereoisomers. Conversion to the corresponding amides (1R,3S)-3 and (1S,3S)-3 was accomplished by treatment of 2 with ammonia. Benzylation of (1R,3S)-3 or (1S,3S)-3 afforded the corresponding 2-benzylcarbolineamide (1R,3S)-4 or (1S,3S)-4. Dehydration of the amide group in (1R,3S)-4 or (1S,3S)-4 yielded the corresponding 2-benzylcarbolinenitrile (1R,3S)-5 or (1S,3S)-5, which was treated with NaBH4 to reductively remove the cyano group. Hydrogenation removed the benzyl-protectin group of 6 resulting in (1R)-7 or (1S)-7, which is then alkylated with methyl vinyl ketone to give the Michael adduct (1R)-8 or (1S)-8. Subsequent Aldol reaction and dehydration afforded the enantiomerically pure indoloquinolizine derivatives (12bR)-9 or (12bS)-9, which was shown to be enantiomerically pure by recording their 1H-NMR spectra in the presence of a chiral shift reagent.
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199319930126
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