THE FIRST SYNTHESIS OF A TRICYCLIC HOMODETIC PEPTIDE EMPLOYING COORDINATED ORTHOGONAL PROTECTION

In an effort to cause significant conformational distortion and thereb y possibly generate a pure SRIF antagonist, we undertook the synthesis of 2, the first homodetic tricyclic peptide. This required five dimen sional orthogonal amino protection and three carboxyl protecting group s to allow the selective closure of the three rings and to differentia te the epsilon-amino groups of the two lysines. We also exploited acid catalyzed removal from the resin to achieve selective deprotection of a side chain carboxyl moiety simultaneously with its partner amino gr oup for subsequent cyclization. Copyright (C) 1996 Elsevier Science Lt d