1-(5,5-dimethyl-2-oxo-1,3,2lambda5-dioxaphosphinan-2-yl)propan-2-one

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

Procedure: A solution mixture of II and III obtained in Reference Example 1 was stirred under cooling with ice and 510 g (10.2 mol) of hydrazine monohydrate was dropwise added thereto. After the completion of dropwise addition, the solution mixture was stirred for 30 minutes (the reaction was completed in ten minutes), and 11.2 kg of 10% by weight hydrochloric acid was added thereto. The solution mixture was stirred for one hour at room temperature and 5.0 kg of the solvent was distilled off. The solution was subjected to salting-out by addition of 1.38 kg of sodium chloride and extracted 2 times with 15.8 kg of chloroform. The chloroform layers were combined and dried over anhydrous sodium sulfate, followed by filtration. The solvent was distilled off, and the residue was dissolved in 3.5 kg of toluene and cooled with ice. The crystal thus precipitated was collected by filtration by means of suction and washed with 1.0 kg of toluene cooled and dried to obtain 1,000 g (yield: 57.5% through 4 steps) of the desired product of 2-acetonyl-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane as colorless crystal. obtained in Reference Example 1 was dropwise added After the completion of dropwise addition the solution mixture was stirred for 30 minutes (the reaction was completed in ten minutes The solution mixture was stirred for one hour at room temperature 5.0 kg of the solvent was distilled off The solution was subjected to salting-out by addition of 1.38 kg of sodium chloride extracted 2 times with 15.8 kg of chloroform dried over anhydrous sodium sulfate followed by filtration The solvent was distilled off the residue was dissolved in 3.5 kg of toluene cooled with ice The crystal thus precipitated was collected by filtration by means of suction washed with 1.0 kg of toluene cooled dried

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

Procedure: 0.69 g (3.7 mmol) of 5,5-dimethyl-2-(1-propynyl)-2-oxo-1,3,2-dioxaphosphorinane (III) was dissolved in 3 ml of acetonitrile, and 0.22 g (4.4 mmol) of hydrazine monohydrate was added thereto. The mixture was left for 30 hours at room temperature. Then, 4.8 g of 10% by weight hydrochloric acid was added thereto and stirred for one hour. The solvent was distilled off to about one-half of its initial volume under reduced pressure, and the reaction mixture diluted with 30 ml of 20% by weight sodium chloride aqueous solution, was extracted 2 times with 40 ml of chloroform. The chloroform layers were combined and dried over anhydrous sodium sulfate, followed by filtration. The solvent was distilled off to obtain 0.77 g (yield: about quantitative amount) of the desired product of 2-acetonyl-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (IV) as colorless solid. The solvent was distilled off to about one-half of its initial volume under reduced pressure the reaction mixture diluted with 30 ml of 20% by weight sodium chloride aqueous solution was extracted 2 times with 40 ml of chloroform dried over anhydrous sodium sulfate followed by filtration The solvent was distilled off

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

Procedure: 0.69 g (3.7 mmol) of 2-allenyl-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (II) was dissolved in 3 ml of acetonitrile, and 0.22 g (4.4 mmol) of hydrazine monohydrate was added thereto. The mixture was left for 30 minutes at room temperature. Then, 4.8 g of 10% by weight hydrochloric acid was added thereto and stirred for one hour. The solvent was distilled off to about one-half its initial volume under reduced pressure and the reaction mixture diluted with 30 ml of 20% by weight sodium chloride aqueous solution, was extracted 2 times with 40 ml of chloroform. The chloroform layers were combined and dried over anhydrous sodium sulfate, followed by filtration. The solvent was distilled off to obtain 0.75 g (yield: about quantitative amount) of the desired product of 2-acetonyl-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (IV) as colorless solid. The solvent was distilled off to about one-half its initial volume under reduced pressure the reaction mixture diluted with 30 ml of 20% by weight sodium chloride aqueous solution was extracted 2 times with 40 ml of chloroform dried over anhydrous sodium sulfate followed by filtration The solvent was distilled off