- Integration of enabling methods for the automated flow preparation of piperazine-2-carboxamide
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Here we describe the use of a new open-source software package and a Raspberry Pi computer for the simultaneous control of multiple flow chemistry devices and its application to a machine-assisted, multi-step flow preparation of pyrazine-2-carboxamide - a component of Rifater, used in the treatment of tuberculosis - and its reduced derivative piperazine-2- carboxamide.
- Ingham, Richard J.,Battilocchio, Claudio,Hawkins, Joel M.,Ley, Steven V.
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- PROCESS FOR THE PREPARATION OF A CHIRAL PIPERAZINE-2-CARBOXYLIC ACID
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The invention relates to a novel process for the preparation of a chiral piperazine-2- carboxylic acid or of a salt thereof of the formula (I). The chiral piperazine-2-carboxylic acid derivatives of the formula (I) are key intermediates for the preparation of fused heteroaryl dihydro pyrimidines which are useful for the treatment and prophylaxis of hepatitis B virus infections.
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Page/Page column 13; 14
(2021/11/06)
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- Piperazine additions to C60 - A facile approach to fullerene substitution
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A range of fullerene monoadducts can be generated via the photochemical reaction of piperazine derivatives with C60. Addend functionality can also be efficiently incorporated by transformation of the hydroxyl-substituted adduct prepared in this fashion. Reaction yields and process simplicity compete with current standard procedures for fullerene mono-functionalisation. The Royal Society of Chemistry 2005.
- Butts, Craig P.,Jazdzyk, Mikael D. S.
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p. 1209 - 1215
(2007/10/03)
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- The preparation and structures of non-hydrocarbon functionalised fullerene-diamine adducts
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Addends based on C2-substituted piperazine are employed to generate C60 monoadducts by photochemical addition, representing the first introduction of non-hydrocarbon addend functionality to fullerenes via the oxidative dehydrogenation reaction of diamines with fullerenes.
- Butts, Craig P.,Jazdzyk, Mikael
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p. 1530 - 1531
(2007/10/03)
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- Method of preventing or limiting reperfusion damage
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There is disclosed a process for preparing (l)-(-)-2-aminocarbonyl)-N-(4-amino-2,6-dichlorophenyl)-4-?5,5-bis(4-fluorophenyl)pentyl!-1-piperazineacetamide which comprises the steps of (a) cyclizing (-)-(S,S)-N1,N2 -bis(1-phenylethyl)-1,2-ethanediamine with 2,3-dibromopropanamide in a reaction-inert solvent in the presence of a base, thus yielding an intermediate; (b) resolving the intermediate of into two stereoisomers and recovering thereby ?1(S),2A,4(S)!-1,4-bis(1-phenylethyl)-2-piperazinecarboxamide; (c) hydrogenolyzing ?1(S),2A,4(S)!-1,4-bis(1-phenylethyl)-2-piperazinecarboxamide under a hydrogen atmosphere in an alkanol in the presence of a hydrogenation catalyst to produce (+) -2-piperazinecarboxamide; (d) reductively N-alkylating (+)-2-piperazinecarboxamide with 5,5-bis(4-fluorophenyl)pentaldehyde under a hydrogen atmosphere in an alkanol in the presence of a hydrogenation catalyst to produce a compound of the formula: STR1 (e) N-alkylating the compound of Formula (VII) with an alkylating reagent of the formula: STR2 wherein W represents a reactive leaving group, in a reaction-inert solvent in the presence of a base to form the nitro analog of the desired compound; and (f) reducing the nitro compound in the presence of a reducing agent in a reaction-inert solvent.
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- Preparation of (S)-piperazine-2-carboxylic acid, (R)-piperazine-2-carboxylic acid, and (S)-piperidine-2-carboxylic acid by kinetic resolution of the corresponding racemic carboxamides with stereoselective amidases in whole bacterial cells
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Whole bacterial cells containing stereospecific amidases were used for the kinetic resolution of racemic piperazine-2-carboxamide and piperidine-2-carboxamide to (S)- and (R)-piperazine-2-carboxylic acid, and (S)-piperidine-2-carboxylic acid, respectively. (S)-Piperazinecarboxylic acid dihydrochloride produced with the biocatalysts Klebsiella terrigena DSM 9174 had an ee value of 99.4% (41% yield), and the ee value of (R)-piperazinecarboxylic acid dihydrochloride obtained with Burkholderia sp. DSM 9925 was 99.0% (22% yield). Using Pseudomonas fluorescens DSM 9924 (S)-piperidine-2-carboxylic acid with an ee value of 97.3% (20% yield) was isolated.
- Eichhorn, Eric,Roduit, Jean-Paul,Shaw, Nicholas,Heinzmann, Klaus,Kiener, Andreas
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p. 2533 - 2536
(2007/10/03)
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