Diphosgene → 3-(3-(((9H-fluoren-9-yl)methoxy)carbonylamino)propanamido)-4-((2S,3R,4S,5S,6S)-3,4,5-triacetoxy-6-(methoxycarbonyl)-tetrahydro-2H-pyran-2-yloxy)benzyl 2-(3-(tert-butyldiphenylsilyloxy)propyl)oxazolidine-3-carboxylate

Participants

Reaction Steps

The construction of the glucuronide-based linker unit with DPO (2) involved a different strategy (Scheme 4). Intermediate 11 was activated with diphosgene and then reacted with oxazoline 12 (prepared in 3 steps from 1,4-butane diol) to afford the desired oxazoline carbamate 13. Removal of the silyl protecting group with fluoride was followed by oxidation to give aldehyde 14. This compound was used in a reductive alkylation reaction with doxorubicin-HCl (15) to give the doxorubicin derivative 16. Lastly, the β-glucuronide protecting groups and Fmoc group were removed in a 2-step sequence with lithium hydroxide and piperidine, and the resulting primary amine was capped with 10 to give the desired β-glucuronide DPO linker 17.

Provenance & Evidence