Patent ID: 6939946

Claim:
A process for modifying a cyclic peptide ring nucleus comprising the steps of: (i) providing a cyclic peptide compound comprising a peptide unit having a γ-hydroxyl group; (ii) opening the ring of said cyclic peptide compound to provide a first linear peptide wherein said peptide unit having a γ-hydroxyl group is the N-terminus peptide unit of said first linear peptide; (iii) cleaving-off said peptide unit having a γ-hydroxyl group to provide a second linear peptide; (iv) attaching at least one amino acid, dipeptide unit or synthetic unit to said second linear peptide to produce a third linear peptide; (v) cyclizing said third linear peptide to produce a modified cyclic peptide compound having a modified ring nucleus; wherein said modified cyclic peptide compound is represented by formula I or II: wherein R is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or heteroaryl group; R2 is —H or —CH 3 ; R3 is —H, —CH 3 , —CH 2 CONH 2 or —CH 2 CH 2 NH 2 ; R4 is —H or —OH; R5 is —OH, —OPO 3 H 2 , or —OSO 3 H; R6 is —H or —OSO 3 H; R7 is —CH 3 or —H; (Y) is represented by the following formula wherein A is —CH 2 ) a — where a=1-4 —CHR′—CHR″—(CH 2 ) b —, where R′ and R″ are independently —H, —OH, C 6 H 5 O—, —SH, —NH 2 , C n H 2n+1 NH—, C n H 2n+1 O—, C n H 2n+1 S— or C n H 2n+1 , where n=1-4 and b=0-1, —(CH 2 ) c —C(O)NH(CH 2 ) d —, where c=1-2 and d=1-2, —N═CH—(CH 2 ) e — where e=0-2, —NR′″(CH 2 ) f —, where R′″ is —H, —C(O)CH 2 NH 2 , —C(O)CH(NH 2 )CH 2 NH 2 or C n H 2n+1 where n=1-4and f=1-3, —CH 2 ) g —SO 2 —(CH 2 ) h — where g=1-2 and h=1-2, where i=1 or 2, or where j is 1 or 2 and Z is an amino group, alkylamino group, or piperidyl amino group; and B is a substituted or unsubstituted C1 to C6 alkyl group; W is a hydrogen or C(O)R where R is as defined above; and pharmaceutically acceptable salts, esters or hydrates thereof.