Dabco → Dimethyl 1,4,6,7-tetrahydropyrano[4,3-b]pyrrole-2,3-dicarboxylate

HRID 1473264

Reaction equation

[O:1]1[CH2:6][CH2:5][C:4](=[N:7]O)[CH2:3][CH2:2]1.[CH3:9][O:10][C:11]([C:13]#[C:14][C:15]([O:17][CH3:18])=[O:16])=[O:12].C1N2CCN(CC2)C1>C1(C)C=CC=CC=1>[NH:7]1[C:13]([C:11]([O:10][CH3:9])=[O:12])=[C:14]([C:15]([O:17][CH3:18])=[O:16])[C:3]2[CH2:2][O:1][CH2:6][CH2:5][C:4]1=2

Participants

Conditions

Temperature: 165 °C

Procedure

A suspension of dihydro-2H-pyran-4(3H)-one oxime (7 g, 60.8 mmol), dimethylacetylene dicarboxylate (9.72 ml, 79 mmol), and DABCO (2.046 g, 18.24 mmol) in Toluene (27.5 ml) were heated to 165° C. After 2 h, the reaction mixture was cooled to ambient temperature, concentrated in vacuo and purified by ISCO (0-100% EtOAc-hexanes) to afford dimethyl 1,4,6,7-tetrahydropyrano[4,3-b]pyrrole-2,3-dicarboxylate (3.2 g, 13.38 mmol, 22.00% yield) as a yellow solid. The residue was dissolved in DMF (30 mL), and treated with Cs2CO3 (5.29 g, 16.23 mmol) and 4-fluorobenzyl bromide (2.023 ml, 16.23 mmol). After 2 h, the reaction mixture was partitioned between EtOAc and sat. aq. NH4Cl. The organic layer was washed with water, brine, dried (MgSO4), filtered and concentrated in vacuo. The residue was purified by ISCO (0-50% EtOAc-hexanes; 120 g column) to afford dimethyl 1-(4-fluorobenzyl)-1,4,6,7-tetrahydropyrano[4,3-b]pyrrole-2,3-dicarboxylate (3.92 g, 11.29 mmol, 18.56% yield) as a yellow oil. LCMS (m/z) ES+=348 (M+1).

Workup

temperaturethe reaction mixture was cooled to ambient temperature
concentrationconcentrated in vacuo
custompurified by ISCO (0-100% EtOAc-hexanes)

Sources & evidence

ORD record: ord-661e15bc5dc7482c8a90bd0547efda7b
Source dataset: uspto-grants-2015_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09012642B2

Linked notes

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