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2-[4-(5-chloro-3-methyl-benzo[<i>b</i>]thiophene-2-sulfonyl)-2-oxo-piperazin-1-yl]-<i>N</i>-[4-guanidino-1-(thiazole-2-carbonyl)-butyl]-acetamide[ No CAS ]
EXAMPLE C. PREPARATION OF 2-OXO-1,4-PIPERAZINEDIACETIC ACID; LACTAM OF ETHYLENEDIAMINETRIACETIC ACID. Approximately 40.8 g of 2-oxo-l-piperazineacetic acid, prepared by the procedure of Example B, and 70 g of deionized water were added to a beaker and stirred for several hours with a magnetic stirrer bar. The contents were filtered using a medium glass frit funnel and vacuum. The filtrate and 20.0 g of bromoacetic acid were added to a beaker and stirred till all the bromoacetic acid had dissolved. The pH was adjusted to approximately 7 with 25% sodium hydroxide solution. The temperature was maintained at less than 25 C. during the caustic addition by cooling in an ice-water bath. The ice-water bath was removed and the mix allowed to stir for approximately 4-5 hours at approximately 35 C. while maintaining the pH at about 7 by the periodic addition of 25% sodium hydroxide solution. The reaction mix was allowed to stand for several hours and then concentrated (in vacuo) to a weight of approximately 90-100 g and filtered using a medium glass frit funnel and vacuum. Volatiles were removed (in vacuo) from the filtrate at a temperature of 55-60 C. and the material dried in a vacuum oven at 55-60 C. for several hours. The lactam of ethylenediaminetriacetic acid was confirmed by proton and carbon NMR.
With hydrogenchloride; sodium hydroxide; In water;
EXAMPLE B. PREPARATION OF 2-OXO-1-PIPERAZINEACETIC ACID; LACTAM OF ETHYLENEDIAMINEDIACETIC ACID. Deionized water (150 g), 25.0 g (0.14 mole) of symmetrical ethylenediaminediacetic acid, and 28 g of concentrated hydrochloric acid were added to a round-bottom reaction flask equipped with a thermometer, temperature controller, water-cooled reflux condenser, and heating mantle. The mixture was stirred with a magnetic stirrer bar and heated at reflux for four hours and cooled. The contents were filtered using a medium glass frit funnel and vacuum. The pH of the filtrate was adjusted to approximately 1.5 with 50% sodium hydroxide solution and filtered with a medium glass frit funnel using vacuum. The pH of the filtrate was adjusted to about 5 with 50% sodium hydroxide solution and the volatiles removed (in vacuo) at a temperature of 60-70 C. The solids were dried in a vacuum oven at 55-60 C. for several hours. The lactam of symmetrical ethylenediaminediacetic acid was confirmed by proton and carbon NMR.
[4-(2-tert-butoxycarbonylaminoethyl)-2-oxopiperazin-1-yl]acetic acid[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
With palladium 10% on activated carbon; hydrogen; In methanol; for 22.0h;Inert atmosphere;
Palladium (0.161 g, 10% on carbon) was added to a mixture of 2-Oxo-1-piperazineacetic acid (0.497 g, 3.14 mmol) and (2-Oxo-ethyl)-carbamic acid tert-butyl ester (0.503 g, 3.16 mmol) in methanol (6.2 mL) under argon. The flask was evacuated and the reaction placed under a hydrogen atmosphere for 22 h. The reaction was filtered through a Celite -plugged filter frit, washed with methanol and DCM, and concentrated in vacuo to afford crude product which was carried to the next step without purification. ESI-MS m/z 324 (M+Na)+.
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