Tyrosine based linkers for the releasable connection of peptides

A compound of the formula

• wherein
• n represents the number 0, 1, 2, 3 or 4,
• m represents the number 0, 1, 2, 3 or 4,
• where m and n together are the number 1, 2, 3, 4, 5 or 6,
• R1 represents tert-butyloxycarbonyl or (9H-fluoren-9-ylmethoxy)carbonyl,
• R2 represents tert-butyloxycarbonyl,
• R3 represents hydrogen, methyl, ethyl, n-propyl, isopropyl or benzyl,
• R4 represents a group of the formula
• where
• * is the point of attachment to the nitrogen,
• p represents the number 1, 2, 3, 4 or 5,
• R5 represents hydrogen, aminocarbonyl, (C1-C4)-alkylaminocarbonyl, phenylaminocarbonyl or a group of the formula
• where
• # is the point of attachment to the carbon atom,
• o represents the number 1, 2, 3, 4 or 5,
• R15 represents hydrogen or (C1-C4)-alkyl,
• R16 represents hydrogen or (C1-C4)-alkyl,
• R17 represents the side group of a natural α-amino acid or its homologues or isomers,
• and
• R18 represents hydrogen or methyl,
• R6 represents —S-trityl, thiolyl, azidyl, acetylenyl, hydroxycarbonyl or amine,
• R7 represents hydrogen or aminocarbonyl,
• R8 represents —S-trityl, thiolyl, azidyl, acetylenyl, hydroxycarbonyl or amine,
• R9 represents hydrogen or (C1-C4)-alkyl,
• R10 represents hydrogen or (C1-C4)-alkyl,
• R11 represents hydrogen or aminocarbonyl,
• R12 represents —S-trityl, thiolyl, azidyl, acetylenyl, hydroxycarbonyl or amine,
• R13 represents the side group of a natural α-amino acid or its homologues or isomers,
• and
• R14 represents hydrogen or methyl,
• or a salt thereof.