1,4-dioxaspiro[4.6]undecan-8-one

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

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

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

Procedure: 8-Amino-1,4-dioxa-spiro[4.6]undecane-8-carboxylic acid was synthesized from 1,4-dioxa-spiro[4.6]undecan-8-one (F. Alonso et al., Tetrahedron 51 (1995), 10259-10280) via the Bucherer-Bergs route in analogy to the procedure described in J. W. Tsang et al., J. Med. Chem. 27 (1984), 1663-1668. The intermediate was suspended in dioxane/water (2.5 ml/5 ml), sodium carbonate (0.732 g, 6.90 mmol) was added, the mixture was cooled in an ice bath and benzyl chloroformate (0.392 ml, dissolved in 2.5 ml of dioxane) was added with stirring. After 4 h, the mixture was partitioned between 2 N hydrochloric acid and EA, the aqueous phase was extracted with EA, the combined organic phrases were washed with water, dried over sodium sulfate and evaporated to dryness to yield a mixture of 8-benzyloxycarbonylamino-1,4-dioxa-spiro[4.6]undecane-8-carboxylic acid and 1-benzyloxycarbonylamino-4-oxo-cycloheptanecarboxylic acid. the mixture was cooled in an ice bath the mixture was partitioned between 2 N hydrochloric acid and EA the aqueous phase was extracted with EA the combined organic phrases were washed with water dried over sodium sulfate evaporated to dryness to yield

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

Procedure: 8-Amino-1,4-dioxa-spiro[4.6]undecane-8-carboxylic acid was synthesized from 1,4-dioxa-spiro[4.6]undecan-8-one (F. Alonso et al., Tetrahedron 51 (1995), 10259-10280) via the Bucherer-Bergs route in analogy to the procedure described in J. W. Tsang et al., J. Med. Chem. 27 (1984), 1663-1668. The intermediate was suspended in dioxane/water (2.5 ml/5 ml), sodium carbonate (0.732 g, 6.90 mmol) was added, the mixture was cooled in an ice bath and benzyl chloroformate (0.392 ml, dissolved in 2.5 ml of dioxane) was added with stirring. After 4 h, the mixture was partitioned between 2 N hydrochloric acid and EA, the aqueous phase was extracted with EA, the combined organic phrases were washed with water, dried over sodium sulfate and evaporated to dryness to yield a mixture of 8-benzyloxycarbonylamino-1,4-dioxa-spiro[4.6]undecane-8-carboxylic acid and 1-benzyloxycarbonylamino-4-oxo-cycloheptanecarboxylic acid. the mixture was cooled in an ice bath the mixture was partitioned between 2 N hydrochloric acid and EA the aqueous phase was extracted with EA the combined organic phrases were washed with water dried over sodium sulfate evaporated to dryness to yield