کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5277989 | 1385593 | 2006 | 5 صفحه PDF | دانلود رایگان |

Synthetic investigations of (1,3′)-bistetrahydroisoquinolines are reported as the key intermediates for the synthesis of ecteinascidin and phthalascidin pentacyclic structure analogues through successive Pictet–Spengler cyclization and intramolecular peptide coupling. The direct Pictet–Spengler reaction between a derivative of l-DOPA and N-protected-α-aminoaldehyde was first extended to the synthesis of cis-(1,3′)-bistetrahydroisoquinoline. After introduction of the required amino acid moiety, an efficient six-membered ring intramolecular peptide coupling gave rise to piperazine derivative structures. Complete structural assignments were corroborated by NMR and X-ray spectroscopic methods. Nevertheless, the optical integrity of the N-protected-α-aminoaldehyde seems to be sensitive to the reaction conditions. Pentacylic structures, having an anti C3–C11 backbone stereochemistry, were obtained from cyclization para- and ortho- to the 3-OH group of the l-DOPA derivative.
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Journal: Tetrahedron Letters - Volume 47, Issue 8, 20 February 2006, Pages 1319–1323