4-[2-(3,5-dioxopiperazin-1-yl)propyl]piperazine-2,6-dione

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

Procedure: A mixture of N-phenylpiperazine (0.81 g, 5 m mole), DMF (13.4 ml), absolute ethanol (3,3 ml), 37% aqueous formaldehyde solution (0.43 ml) and dl-1,2-bis(3,5-dioxopiperazin-1-yl)-propane (1.34 g, 5 m mole) was stirred at room temperature for 48 hours. Then, the precipitates thus obtained were collected and were washed with absolute ethanol and then with ether. The washed precipitates were dried under a reduced pressure to give the titled compound (1.39 g; yield 62%). The compound obtained in this Example was proved to be identical with the compound described in Example 10 on the basis of the melting point and IR Spectrum. Then, the precipitates thus obtained were collected were washed with absolute ethanol The washed precipitates were dried under a reduced pressure

Conditions: temp:70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of N-methylpiperazine (2.21 ml, 20.0 m mole), DMF (25 ml), chloroform (6 ml) and 1,2-bis(3,5-dioxopiperazin-1-yl)-propane (2.68 g, 10.0 m mole) was stirred at 70° C. for ten minutes. The mixture was treated with 37% aqueous formaldehyde solution (1.62 ml) and was stirred at the same temperature for further 1.5 hours. Then, the same procedure as in Example 3 was made to give the titled compound (2.7 g; yield 55%). was stirred at the same temperature for further 1.5 hours

Conditions: temp:70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of N-methylpiperazine (2.21 ml, 20.0 m mole), DMF (25 ml), chloroform (6 ml) and 1,2-bis(3,5-dioxopiperazin-1-yl)-propane (2.68 g, 10.0 m mole) was stirred at 70° C. for ten minutes. The mixture was treated with 37% aqueous formaldehyde solution (1.62 ml) and was stirred at the same temperature for further 1.5 hours. Then, the same procedure as in Example 3 was made to give the titled compound (2.7 g; yield 55%). was stirred at the same temperature for further 1.5 hours

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of N-phenylpiperazine (2.9 g, 17.7 m mole), DMF (20 ml), absolute ethanol (5 ml) and dl-1,2-bis(3,5-dioxopiperazin-1-yl)-propane (2,0 g, 7.4 m mole) was stirred at 150° C. for ten minutes. The mixture was treated with 37% aqueous formaldehyde solution (1.40 ml) and was stirred at the same temperature for further 1.5 hours. Then, the same procedure as in Example 3 was made to give the titled compound (2.9 g; yield 88%). was stirred at the same temperature for further 1.5 hours

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

Procedure: A mixture of dl-1,2-bis(3,5-dioxopiperazin-1-yl)-propane (26.8 g, 0.1 mole), morpholine (27 ml, 0.3 mole) and absolute ethanol (100 ml) was heated to reflux. To the mixture, 37% aqueous formaldehyde solution (27 ml) was added gradually and then the reaction mixture was refluxed for further 15 minutes. The cooled mixture was filtered and the filtrate was allowed to stand in the refrigerator. Then resulting white crystals were collected and washed with ethyl acetate to give the titled compound (39.6 g; yield 84.9%). was heated to reflux the reaction mixture was refluxed for further 15 minutes The cooled mixture was filtered Then resulting white crystals were collected washed with ethyl acetate

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

Procedure: A mixture of N-phenylpiperazine (0.81 g, 5 m mole), DMF (13.4 ml), absolute ethanol (3,3 ml), 37% aqueous formaldehyde solution (0.43 ml) and dl-1,2-bis(3,5-dioxopiperazin-1-yl)-propane (1.34 g, 5 m mole) was stirred at room temperature for 48 hours. Then, the precipitates thus obtained were collected and were washed with absolute ethanol and then with ether. The washed precipitates were dried under a reduced pressure to give the titled compound (1.39 g; yield 62%). The compound obtained in this Example was proved to be identical with the compound described in Example 10 on the basis of the melting point and IR Spectrum. Then, the precipitates thus obtained were collected were washed with absolute ethanol The washed precipitates were dried under a reduced pressure

Conditions: temp:70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of N-methylpiperazine (2.21 ml, 20.0 m mole), DMF (25 ml), chloroform (6 ml) and 1,2-bis(3,5-dioxopiperazin-1-yl)-propane (2.68 g, 10.0 m mole) was stirred at 70° C. for ten minutes. The mixture was treated with 37% aqueous formaldehyde solution (1.62 ml) and was stirred at the same temperature for further 1.5 hours. Then, the same procedure as in Example 3 was made to give the titled compound (2.7 g; yield 55%). was stirred at the same temperature for further 1.5 hours

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of N-phenylpiperazine (2.9 g, 17.7 m mole), DMF (20 ml), absolute ethanol (5 ml) and dl-1,2-bis(3,5-dioxopiperazin-1-yl)-propane (2,0 g, 7.4 m mole) was stirred at 150° C. for ten minutes. The mixture was treated with 37% aqueous formaldehyde solution (1.40 ml) and was stirred at the same temperature for further 1.5 hours. Then, the same procedure as in Example 3 was made to give the titled compound (2.9 g; yield 88%). was stirred at the same temperature for further 1.5 hours

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

Procedure: A mixture of dl-1,2-bis(3,5-dioxopiperazin-1-yl)-propane (26.8 g, 0.1 mole), morpholine (27 ml, 0.3 mole) and absolute ethanol (100 ml) was heated to reflux. To the mixture, 37% aqueous formaldehyde solution (27 ml) was added gradually and then the reaction mixture was refluxed for further 15 minutes. The cooled mixture was filtered and the filtrate was allowed to stand in the refrigerator. Then resulting white crystals were collected and washed with ethyl acetate to give the titled compound (39.6 g; yield 84.9%). was heated to reflux the reaction mixture was refluxed for further 15 minutes The cooled mixture was filtered Then resulting white crystals were collected washed with ethyl acetate