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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.
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.
Estropipate, also known as piperazine estrone sulfate and sold under the brand names Harmogen, Improvera, Ogen, Ortho-Est, and Sulestrex among others, is an estrogen medication which is used mainly in menopausal hormone therapy in the treatment of menopausal symptoms.
Terazosin synthesis: [6] Reaction of piperazine with 2-furoyl chloride followed by catalytic hydrogenation of the furan ring leads to 2 . This, when heated in the presence of 2-chloro-6,7-dimethoxyquinazolin-4-amine ( 1 ) undergoes direct alkylation to terazosin ( 3 ).
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]
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]
1-(2-Pyrimidinyl)piperazine (1-PP, 1-PmP) is a chemical compound and piperazine derivative. It is known to act as an antagonist of the α 2 -adrenergic receptor (K i = 7.3–40 nM) [ 1 ] and, to a much lesser extent, as a partial agonist of the 5-HT 1A receptor (K i = 414 nM; E max = 54%).