Biomedical Engineering Reference
In-Depth Information
SCHEME 7.18
Synthesis of natural product-like diaza-bridged heterocycles through Pictet-
Spengler intramolecular cyclization. Reagents and conditions: (i) R
1
NH
2
, DMSO, 60
◦
C; (ii)
Fmoc-Trp(Boc)-OH, HATU, DIEA, DMF, rt; (iii) Fmoc(
O
-diTBS)DOPA, HATU, DIEA,
DMF, rt; (iv) (a) 25% piperidine, rt; (b) R
2
COOH, DIC, HOBt, DIEA, rt; (v) R
3
NCO, DIEA,
DCE, rt; (vi) neat formic acid, rt; (vii) neat formic acid, 60
◦
C. (Adapted from [40], with
permission; copyright
C
2006 American Chemical Society.)
