tert-butyl-[3-(1,3-oxazolidin-2-yl)propoxy]-diphenylsilane

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of the 4-(tert-butyldiphenylsilyloxy)butanal (235 mg, 0.72 mmol) in benzene (3 ml) was added dropwise to a solution of hydroxy ethylamine (44 μL, 0.72 mmol) in benzene (3 mL). Powdered molecular sieves (4 Å, 600 mg) were added and the mixture was stirred for 1.5 h, before being filtered through a 20 μm Millipore syringe filter and concentrated. This gave 12 which was used directly and immediately in the synthesis of 13 (infra): 1H NMR(C6D6); δ1.18 (s, 9H), 1.65-1.82 (m, 2H), 2.62 (m, 2H), 3.33 (dd, 3H, J=6.1, 7.5 Hz), 3.69 (t, 3H, J=6.1 Hz), 4.26 (t, 1H), 7.23 (dd, 6H, J=1.9, 3.1 Hz), 7.79 (m, 4H). Powdered molecular sieves (4 Å, 600 mg) were added before being filtered through a 20 μm Millipore syringe filter concentrated

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of the 4-(tert-butyidiphenylsilyloxy)butanal (235 mg, 0.72 mmol) in benzene (3 ml) was added dropwise to a solution of hydroxy ethylamine (44 μL, 0.72 mmol) in benzene (3 mL). Powdered molecular sieves (4 Å, 600 mg) were added and the mixture was stirred for 1.5 h, before being filtered through a 20 μm Millipore syringe filter and concentrated. This gave 12 which was used directly and immediately in the synthesis of 13 (infra): 1H NMR (C6D6); δ1.18 (s, 9H), 1.65-1.82 (m, 2H), 2.62 (m, 2H), 3.33 (dd, 3H, J=6.1, 7.5 Hz), 3.69 (t, 3H, J=6.1 Hz), 4.26 (t, 1H), 7.23 (dd, 6H, J=1.9, 3.1 Hz), 7.79 (m, 4H). Powdered molecular sieves (4 Å, 600 mg) were added before being filtered through a 20 μm Millipore syringe filter concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of the 4-(tert-butyidiphenylsilyloxy)butanal (235 mg, 0.72 mmol) in benzene (3 ml) was added dropwise to a solution of hydroxy ethylamine (44 μL, 0.72 mmol) in benzene (3 mL). Powdered molecular sieves (4 Å, 600 mg) were added and the mixture was stirred for 1.5 h, before being filtered through a 20 μm Millipore syringe filter and concentrated. This gave 12 which was used directly and immediately in the synthesis of 13 (infra): 1H NMR (C6D6); δ1.18 (s, 9H), 1.65-1.82 (m, 2H), 2.62 (m, 2H), 3.33 (dd, 3H, J=6.1, 7.5 Hz), 3.69 (t, 3H, J=6.1 Hz), 4.26 (t, 1H), 7.23 (dd, 6H, J=1.9, 3.1 Hz), 7.79 (m, 4H). Powdered molecular sieves (4 Å, 600 mg) were added before being filtered through a 20 μm Millipore syringe filter concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of the 4-(tert-butyldiphenylsilyloxy)butanal (235 mg, 0.72 mmol) in benzene (3 ml) was added dropwise to a solution of hydroxy ethylamine (44 μL, 0.72 mmol) in benzene (3 mL). Powdered molecular sieves (4 Å, 600 mg) were added and the mixture was stirred for 1.5 h, before being filtered through a 20 μm Millipore syringe filter and concentrated. This gave 12 which was used directly and immediately in the synthesis of 13 (infra): 1H NMR(C6D6); δ1.18 (s, 9H), 1.65-1.82 (m, 2H), 2.62 (m, 2H), 3.33 (dd, 3H, J=6.1, 7.5 Hz), 3.69 (t, 3H, J=6.1 Hz), 4.26 (t, 1H), 7.23 (dd, 6H, J=1.9, 3.1 Hz), 7.79 (m, 4H). Powdered molecular sieves (4 Å, 600 mg) were added before being filtered through a 20 μm Millipore syringe filter concentrated