2-(3,4-dihydroxyphenyl)acetohydrazide

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a suspension of 1.10 g of (S)-(2-oxo-3-azetidinyl)carbamic acid, phenylmethyl ester (5.0 mmol) in 40 ml of dry ethyl acetate, 0.45 ml (5.0 mmol) of chlorosulfonyl isocyanate was added with stirring. The mixture was stirred for 1 hour at room temperature and then cooled to 0° C. After the dropwise addition of a solution of 2.09 ml (15.0 mmol) of triethylamine in 10 ml of dry dichloromethane and solution A, stirring was continued for 2.5 hours at 0° C. Ice water was added, and the organic layer was separated and washed successively with cold buffer solution (citrate pH 2) and brine. Drying (magnesium sulfate) and evaporation in vacuo gave a residue which solidified by stirring with ether; yield: 2.1 g. was added The mixture was stirred for 1 hour at room temperature stirring the organic layer was separated washed successively with cold buffer solution (citrate pH 2) and brine Drying (magnesium sulfate) and evaporation in vacuo gave a residue which

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3.58 g (12.7 mmol) of the t-butoxycarbonyl protected precursor was added to a -10° C. cold mixture of 1.38 ml (12.7 mmol) of anisole and 40 ml of trifluoroacetic acid. After stirring for 30 minutes at 0° C., the solvent was removed in vacuo and the residue was stirred with dry ether, collected by suction and dried in vacuo over phosphorous pentoxide; yield: 3.77 g. 2.59 ml (14.0 mmol) of N-methyl-N-trimethylsilyltrifluoroacetamide was added to a suspension of 1.38 g (4.65 mmol) of this trifluoroacetic acid salt in 20 l of dry acetonitrile. After stirring for 30 minutes at room temperature, the mixture was evaporated in vacuo and the residue was taken up in a few ml of dry ether and 0.6 ml of methanol was added. The solution was evaporated again in vacuo and the residue was stirred with petroleum ether until the sticky material became crystalline; yield: 0.79 g. the solvent was removed in vacuo the residue was stirred with dry ether collected by suction dried in vacuo over phosphorous pentoxide After stirring for 30 minutes at room temperature the mixture was evaporated in vacuo was added The solution was evaporated again in vacuo the residue was stirred with petroleum ether until the sticky material

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3.58 g (12.7 mmol) of the t-butoxycarbonyl protected precursor was added to a -10° C. cold mixture of 1.38 ml (12.7 mmol) of anisole and 40 ml of trifluoroacetic acid. After stirring for 30 minutes at 0° C., the solvent was removed in vacuo and the residue was stirred with dry ether, collected by suction and dried in vacuo over phosphorous pentoxide; yield: 3.77 g. 2.59 ml (14.0 mmol) of N-methyl-N-trimethylsilyltrifluoroacetamide was added to a suspension of 1.38 g (4.65 mmol) of this trifluoroacetic acid salt in 20 l of dry acetonitrile. After stirring for 30 minutes at room temperature, the mixture was evaporated in vacuo and the residue was taken up in a few ml of dry ether and 0.6 ml of methanol was added. The solution was evaporated again in vacuo and the residue was stirred with petroleum ether until the sticky material became crystalline; yield: 0.79 g. the solvent was removed in vacuo the residue was stirred with dry ether collected by suction dried in vacuo over phosphorous pentoxide After stirring for 30 minutes at room temperature the mixture was evaporated in vacuo was added The solution was evaporated again in vacuo the residue was stirred with petroleum ether until the sticky material

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3.58 g (12.7 mmol) of the t-butoxycarbonyl protected precursor was added to a -10° C. cold mixture of 1.38 ml (12.7 mmol) of anisole and 40 ml of trifluoroacetic acid. After stirring for 30 minutes at 0° C., the solvent was removed in vacuo and the residue was stirred with dry ether, collected by suction and dried in vacuo over phosphorous pentoxide; yield: 3.77 g. 2.59 ml (14.0 mmol) of N-methyl-N-trimethylsilyltrifluoroacetamide was added to a suspension of 1.38 g (4.65 mmol) of this trifluoroacetic acid salt in 20 l of dry acetonitrile. After stirring for 30 minutes at room temperature, the mixture was evaporated in vacuo and the residue was taken up in a few ml of dry ether and 0.6 ml of methanol was added. The solution was evaporated again in vacuo and the residue was stirred with petroleum ether until the sticky material became crystalline; yield: 0.79 g. the solvent was removed in vacuo the residue was stirred with dry ether collected by suction dried in vacuo over phosphorous pentoxide After stirring for 30 minutes at room temperature the mixture was evaporated in vacuo was added The solution was evaporated again in vacuo the residue was stirred with petroleum ether until the sticky material