US 12,071,450 B2
Salts of conjugates for cancer therapy
Stela Gengrinovitch, Kfar Hanania (IL)
Assigned to Biosight Ltd., Lod (IL)
Filed by Biosight Ltd., Lod (IL)
Filed on Aug. 30, 2021, as Appl. No. 17/460,335.
Application 17/460,335 is a continuation in part of application No. 15/780,704, granted, now 11,104,698, previously published as PCT/IL2016/051287, filed on Dec. 1, 2016.
Claims priority of provisional application 62/370,257, filed on Aug. 3, 2016.
Claims priority of provisional application 62/262,428, filed on Dec. 3, 2015.
Prior Publication US 2021/0395285 A1, Dec. 23, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. C07H 1/00 (2006.01); C07H 19/09 (2006.01)
CPC C07H 1/00 (2013.01) [C07H 19/09 (2013.01)] 6 Claims
 
1. A process for preparing a compound of formula (1) comprising the step of:
(a) coupling a compound of formula (i) with a drug of formula D or a protected derivative thereof of formula D-(P3)n in the presence of a coupling reagent to afford an intermediate of formula (ii), wherein D is cytarabine or a residue thereof, and wherein the cytarabine is attached to the C═O group via its amine group; and
(b) removing the protecting groups P1, P2 and removing P3 if present, with a strong acid (Y) or with a deprotecting agent followed by a strong acid (Y) so as to generate a salt represented by the formula (1):

OG Complex Work Unit Chemistry
wherein P1 is a carboxy protecting group, P2 is an amino protecting group, P3 is a protecting group located on one or more functional groups on the drug D, n is 0, 1, 2 or 3; and Y is a strong acid.