Method for preparing Fmoc-based hydrolysable linkers
View Patent ↗A novel process for the production of Fmoc (9H-fluoren-9-ylmethoxycarbonyl)-based compounds is provided, wherein a protecting group for the 9-hydroxymethyl group of the fluorene ring system is utilized. These compounds are useful for the modification of protein and peptide drugs.
1. A method of preparing a compound according to formula 1:
wherein PG is a silyl protecting group and at least one of position 1, 2, 3, 4, 5, 6, 7 or 8 is bound to radical Y;
Y is a radical containing a N-maleimidyl-moiety having a structure
R 1 is a (C 1 -C 8 )-alkyl;
R 2 is selected from the group consisting of —C(O)NR—, —C(O)NR—(C 1 -C 8 )-alkyl-NR—, —NRC(O)— and —NRC(O)—(C 1 -C 8 )-alkyl-NR, wherein R is independently either hydrogen or C 1 -C 8 -alkyl;
at least one of an available position 1, 2, 3, 4, 5, 6, 7 or 8 is optionally bound to radical X;
X is —SO 3 R 3 ;
R 3 is independently selected from the group consisting of hydrogen, (C 1 -C 8 )-alkyl and (C 1 -C 8 )-alkyl-R 4 ; and
R 4 is a polymer;
said method comprises the steps of
reacting the 9-hydroxymethyl group of a compound of formula 2:
wherein at least one of position 1, 2, 3, 4, 5, 6, 7 or 8 is bound to an amine, with a silyl protecting reagent introducing PG,
and subsequently reacting said compound with an N-maleimidyl reagent to form the compound of formula (1).
2. The method according to claim 1 , wherein said silyl protecting reagent is a silyl halide.
3. The method according to claim 2 , wherein said halide is tert-butyldimethylsilyl chloride (tBDMS-Cl).
4. The method according to claim 3 , wherein said reaction with tBDMS-Cl is performed with imidazole in dimethylformamide (DMF).
5. The method according to claim 4 , wherein said N-maleimidyl-reagent is maleimidoalkylic acid.
6. The method according to claim 3 , wherein at least one of an available position 1, 2, 3, 4, 5, 6, 7 or 8 is bound to radical X.
7. A compound of the formula 1,
wherein PG is a silyl protecting group and at least one of position 1, 2, 3, 4, 5, 6, 7 or 8 is bound to radical Y; and at least one of an available position 1, 2, 3, 4, 5, 6, 7 or 8 is optionally bound to radical X;
Y is a N-maleimidyl-containing moiety having a structure:
X is —SO 3 R 3 —;
R 3 is independently selected from the group consisting of hydrogen, (C 1 -C 8 )-alkyl and (C 1 -C 8 )-alkyl-R 4 ;
R 4 is a polymer;
R 1 is a (C 1 -C 8 )-alkyl; and
R 2 is selected from the group consisting of —C(O)NR—, —C(O)NR—(C 1 -C 8 )-alkyl-NR—, NRC(O)— and —NRC(O)—(C 1 -C 8 )-alkyl-NR—, wherein R is hydrogen or C 1 -C 8 -alkyl.
8. The compound according to claim 7 , wherein PG is a t-butyldimethylsilyl protecting group.