Search results
Results from the WOW.Com Content Network
Piperazine is freely soluble in water and ethylene glycol, but insoluble in diethyl ether. It is a weak base with two pK b of 5.35 and 9.73 at 25 °C.; the pH of a 10% aqueous solution of piperazine is 10.8–11.8. Piperazine readily absorbs water and carbon dioxide from the air.
Reaction of the lactam-derived enol phosphates 4 of 2,5-diketopiperazines with palladium catalyzed reactions (reduction, Suzuki and Stille cross-coupling reactions) enables the synthesis of a range of functionalised 1,4-dihydropyrazines 5 which can be aromatized to 1,4-pyrazines 6 in the presence of acid.
In the Staedel–Rugheimer pyrazine synthesis (1876), 2-chloroacetophenone is reacted with ammonia to the amino ketone, then condensed and then oxidized to a pyrazine. [5] A variation is the Gutknecht pyrazine synthesis (1879) also based on this selfcondensation , but differing in the way the alpha-ketoamine is synthesised.
Piperidine is also commonly used in chemical degradation reactions, such as the sequencing of DNA in the cleavage of particular modified nucleotides. Piperidine is also commonly used as a base for the deprotection of Fmoc-amino acids used in solid-phase peptide synthesis.
Aminoethylpiperazine (AEP) is a derivative of piperazine. This ethyleneamine contains three nitrogen atoms; one primary, one secondary and one tertiary. It is a corrosive organic liquid and can cause second or third degree burns. Aminoethylpiperazine can also cause pulmonary edema as a result of inhalation. It is REACH and TSCA registered. [1]
N-Methylpiperazine is a common building block used in organic synthesis. [2] For example, N-methylpiperazine is used in the manufacture of various pharmaceutical drugs including cyclizine, [3] meclizine, and sildenafil. The lithium salt, lithium N-methylpiperazide, is used as a reagent in organic synthesis for protection of aryl aldehydes. [4]
Mechanochemistry (or mechanical chemistry) is the initiation of chemical reactions by mechanical phenomena. Mechanochemistry thus represents a fourth way to cause chemical reactions, complementing thermal reactions in fluids, photochemistry, and electrochemistry. Conventionally mechanochemistry focuses on the transformations of covalent bonds ...
An N-alkylation of the piperazine ring with 3-methylbenzylchloride completes the synthesis. [27] Alternatively, the last step can be replaced by a reductive N-alkylation with 3-methylbenzaldehyde. The reductive agent is hydrogen, and Raney nickel is used as a catalyst. [28] [29]