Piperazine structure

Phenothiazine antipsychotics can be divided in the aliphatic phenothiazines with a dimethylamino-propyl group, those with a piperazine structure and agents with a piperidine structure. 

Substituting different chemical groups onto the basic piperazine structure creates piperazine derivatives... 

For a few years after the development of the first interfacial composite membranes, it was believed that the amine portion of the reaction chemistry had to be polymeric to obtain good membranes. This is not the case, and the monomeric amines, piperazine and phenylenediamine, have been used to form membranes with very good properties. Interfacial composite membranes based on urea or amide bonds are subject to degradation by chlorine attack, but the rate of degradation of the membrane is slowed significantly if tertiary aromatic amines are used and the membranes are highly crosslinked. Chemistries based on all-aromatic or piperazine structures are moderately chlorine tolerant and can withstand very low level exposure to chlorine for prolonged periods or exposure to ppm levels... 

Saframycins. An antibiotic complex (to date 22 known components) from cultures of Streptomyces la-vendulae. The S. contain tetrahydroisoquinoline units dimerized via a piperazine structure. They have anti-neoplastic activity and are active against Gram-positive bacteria, e. g., S. B C2gH3,N308, Mr 537.57, orange prisms, mp. 108-109 C, [a]g,°-54.4° (CH3OH). 

Poly(amido-amines) having more than one basic nitrogen in their repeating unit are also capable of forming in aqueous solution stable complexes with heavy metal ions, e.g., with the Cu ion, with the exception of those in which the aminic part has a piperazinic structure (13,14). When complexes are formed, sharp stability constants may be determined. Furthermore, solid Cu2+ complexes have been isolated in several instances, having a well defined composition, namely one Cu ion per unit. Thus, in complex formation with metal ions poly(amido-amines) also exhibit a quite unusual behavior among polyelectrolytes. 

Depending upon the structure of the substrates 49, 52, and 56 hexahydropyrido[l,2-n]-[3,l]benzoxazines 50, 54, 2-aminobenzaldehyde 53, 1-substituted piperidones 51, 55, 57, 3,4,5,6-tetrahydropyridinium salt 58, or their mixture was obtained during the oxidation of 1-(2-hydroxymethyl-, 2-formyl- and 2-acetylphenyl)piperazines (49, 52, 56) with Hg(II)-EDTA complex (Schemes 6-8) (79AP219, 98ZN(B)37, 98ZN(B)1369). 

Replacement of the methyl group of the piperazine-substituted phenothiazines by some more polar group such as hydroxyethyl fragment leads to a further small increase in potency. It should be noted at this point that all phenothiazines manifest a series of side effects. The given set of these varies, however, with the side chains. The availability of the great variety of such structural variations makes it more likely that some drug will be found that a given individual will tolerate. 

Alteration of the structural pattern produces a pair of adrenergic a-blocking agents which serve as anti hypertensives. These structures are reminiscent of prazoci n. Reaction of piperazine with 2-furoy1 chloride followed by catalytic reduction of the furan ring leads to synthon 69. This, when heated... 

Alfuzosin (91) is a prazosin-like hypotensive adrenergic a-1 receptor blocker with the special structural feature that two carbons have been excised conceptually from the piperazine ring normally present in this series. Following the usual sequence for this series, reaction of 4-amino-2-chloro-7-dimethoxyquinazoline (89) with the tetrahydro-2-furyl amide of 3-methylaminopropyla-mine (90) gives alfuzosin (91) [25], Alfuzosin is claimed to cause less orthostatic hypotention (dizziness or fainting upon sudden rising) than prazosin. 

A variety of inorganic (31,87) and organic bases have been added to the catalyst to improve selectivity. The effectiveness of organic bases is very sensitive to structure. Morpholine is an effective inhibitor, more so than /Si-melhylmorphollne > N-elhylmorpholine > 3,5-dimethylmorpholine (55). Piperazine is effective, but ethanolamine and ethylenediamine are poisons. 

According to a hypothesis launched by Larionov et al in the 1960s, some new nitrogen mustard derivatives were developed. They contain metabolites and heterocyclic structures as carriers of the cytotoxic chloroethylamine groups. By this way the synthesis of aliylating metabolites started melphalan (sarcolysine) as L- or DL-phenylalanine derivative prospidine with a tricyclic piperazine moiety and chlorambucil as butyric acid derivative. It was proven that each alkylating metabolite has its own spectrum of selective antitumor activity. 

Lopez-Rodriguez ML et al. (1996) Synthesis and structure-activity relationships of a new model of arylpiperazines. 1. 2-[[4-(o-Methoxyphenyl)piperazin-l-yl]methyl]-1, 3-dioxoperhydroimidazo[l,5-alpha]pyridine a selective 5-HTlA receptor agonist. J Med Chem 39(22) 4439-4450... 

Researchers at Novo Nordisk have found that certain acyl piperazines are potent H3 antagonists [125, 126]. Examples include structures (51) and (52), both of which have a if of 1.2 nM against human H3. The group... 

The presence of triethylenetetramine in the hydrothermal synthesis of open-framework zinc phosphates results in a number of frameworks with one- to three-dimensional structures. The structures include one-dimensional ladders, two-dimensional layer structures, and one structure where the tetramine is bound to the zinc center. The structural type was highly sensitive to the relative concentration of the amine and phosphoric acid.411 Piperazine and 2-methylpiperazine can be used as templating molecules in solvothermal syntheses of zinc phosphates. The crystallization processes of the zinc compounds were investigated by real time in situ measurements of synchrotron X-ray powder diffraction patterns.412... 

An open-framework zinc phosphate synthesized under mild hydrothermal conditions possesses two interpenetrating helical channels.414 Piperazine phosphate yields a variety of open framework structures in reaction with zinc, including linear chain, layer, and three-dimensional systems.415... 

The crystal structures of 4-phenyl-2- 4-[4-(2-pyrimidinyl)piperazin-l-yl]butyl -2,3,5,6,7,8-hexahydro-177-pyrido[l,2-c][l,3]oxazine-l,3-dione <1995ZK899>, 4-cyano-l-phenyl-l-trifluoromethyl-2,3-dihydro-l/7-pyrido[l,2-r-]pyrimidin-... 

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