1,4,8-trioxaspiro[4.5]decane-7,9-dione

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

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

Procedure: To a solution of 3,3-(ethylenedioxy)glutaric acid (12.26 g, 64.50 mmole) in 300 ml of tetrahydrofuran maintained at 0° C. under nitrogen was added dropwise a solution of dicyclohexylcarbodiimide (13.60 g, 65.91 mmole) in 100 ml of tetrahydrofuran. The resulting suspension was stirred at room temperature overnight under nitrogen and the solvent was evaporated under vacuum. The residue was suspended in benzene, shaken thoroughly and filtered through silica gel packed in a column (10 cm long, SiO2, 60-200 mesh, benzene). The filtrate was evaporated under vacuum to provide the anhydride (8.268 g, 75% yield) as a white crystalline solid melting at about 111° C. to about 112° C. the solvent was evaporated under vacuum shaken thoroughly filtered through silica gel The filtrate was evaporated under vacuum

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

Procedure: To a solution of 3,3-(ethylenedioxy)glutaric acid (12.26 g, 64.50 mmole) in 300 ml of tetrahydrofuran maintained at 0° C. under nitrogen was added dropwise a solution of dicyclohexylcarbodiimide (13.60 g, 65.91 mmole) in 100 ml of tetrahydrofuran. The resulting suspension was stirred at room temperature overnight under nitrogen and the solvent was evaporated under vacuum. The residue was suspended in benzene, shaken thoroughly and filtered through silica gel packed in a column (10 cm long, SiO2, 60-200 mesh, benzene). The filtrate was evaporated under vacuum to provide the anhydride (8.268 g, 75% yield) as a white crystalline solid melting at about 111° C. to about 112° C. the solvent was evaporated under vacuum shaken thoroughly filtered through silica gel The filtrate was evaporated under vacuum

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

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

Procedure: To a solution of 3,3-(ethylenedioxy)glutaric acid (12.26 g, 64.50 mmole) in 300 ml of tetrahydrofuran maintained at 0° C. under nitrogen was added dropwise a solution of dicyclohexylcarbodiimide (13.60 g, 65.91 mmole) in 100 ml of tetrahydrofuran. The resulting suspension was stirred at room temperature overnight under nitrogen and the solvent was evaporated under vacuum. The residue was suspended in benzene, shaken thoroughly and filtered through silica gel packed in a column (10 cm long, SiO2, 60-200 mesh, benzene). The filtrate was evaporated under vacuum to provide the anhydride (8.268 g, 75% yield) as a white crystalline solid melting at about 111° C. to about 112° C. the solvent was evaporated under vacuum shaken thoroughly filtered through silica gel The filtrate was evaporated under vacuum

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

Procedure: To a solution of 3,3-(ethylenedioxy)glutaric acid (12.26 g, 64.50 mmole) in 300 ml of tetrahydrofuran maintained at 0° C. under nitrogen was added dropwise a solution of dicyclohexylcarbodiimide (13.60 g, 65.91 mmole) in 100 ml of tetrahydrofuran. The resulting suspension was stirred at room temperature overnight under nitrogen and the solvent was evaporated under vacuum. The residue was suspended in benzene, shaken thoroughly and filtered through silica gel packed in a column (10 cm long, SiO2, 60-200 mesh, benzene). The filtrate was evaporated under vacuum to provide the anhydride (8.268 g, 75% yield) as a white crystalline solid melting at about 111° C. to about 112° C. the solvent was evaporated under vacuum shaken thoroughly filtered through silica gel The filtrate was evaporated under vacuum