88547-15-3Relevant academic research and scientific papers
EPIDITHIODIOXOPIPERAZINE COMPOUND OR ITS DERIVATIVES, AND THE USE THEREOF
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Paragraph 387; 392-394, (2014/12/12)
The present invention relates to an epidithiodioxopiperazine derivative represented by the Chemical Formula 1 or its reduced derivative; a method for preparing a compound represented by Chemical Formula 1 having improved intracellular permeability and mim
Method for Preparation of Piperazindione Derivatives
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Page/Page column 9, (2011/06/26)
A process for preparing piperazinedione derivatives of the formula I in which R1 is hydrogen, alkyl, alkenyl, alkynyl and alkylcarbonyl,R2 is hydrogen, alkyl, alkenyl, C3-C4-alkynyl and C(═O)R11,Rsup
Comparative study of synthetic approaches to 1- arylmethylenepyrazino[2,1-b]quinazoline-3,6-diones
Cledera, Pilar,Avendano, Carmen,Menendez, J. Carlos
, p. 12349 - 12360 (2007/10/03)
The transformation of 3-arylmethylenepiperazine-2,5-diones (1) into 1- arylmethylene-2,4-dihydro-1H-pyrazino[2,1-b]quinazoline-3,6-diones (2) was studied. Four synthetic methods were compared, namely direct condensation with the product of the reaction be
THE "GAS-SOLID-PHASE" 2,5-DIOXOPIPERAZINE SYNTHESIS. CYCLIZATION OF VAPOROUS DIPEPTIDES ON SILICA SURFACE
Basiuk, Vladimir,Gromovoy, Taras Yu.
, p. 461 - 466 (2007/10/02)
The "gas-solid-phase" method is used for the preparation of both symmetric and asymmetric 2,5-dioxopiperazines via cyclization of vaporous linear dipeptides in the presence of silica.
Synthesis, Antibacterial Activities, and Pharmacological Properties of Enantiomers of Temafloxacin Hydrochloride
Chu, Daniel T. W.,Nordeen, Carl W.,Hardy, Dwight J.,Swanson, Robert N.,Giardina, William J.,et al.
, p. 168 - 174 (2007/10/02)
Temafloxacin hydrochloride is a potent member of the 4-pyridone-3-carboxylic acid class of antibacterial agents and is currently under clinical development as a broad-spectrum antimicrobial agent.It is a racemate having a chiral center at the C3 of the 7-piperazin-1-yl group.The two enantiomers were synthesized and tested for their antibacterial activities.Although no difference in in vitro antibacterial activities was observed, a minor difference in in vivo antibacterial activities was observed.However, they both exhibited similar pharmacological profiles.
N-Hydroxy Amides. Part 6. Synthesis and Spectroscopic Properties of 1-Hydroxypiperazine-2,5-diones
Akiyama, Masayasu,Katoh, Akira,Tsuchiya, Yuko
, p. 235 - 239 (2007/10/02)
1-Hydroxypiperazine-2,5-diones (3a-f) are prepared in good yields, starting with Boc-L-amino acids and N-benzyloxyglycine methyl ester.The rate of cyclisation for N-hydroxy and N-benzyloxydipeptide methyl esters are 38-77 times as large as that of phenyla
First-Order Rate Constans for the Racemization of Each Component in a Mixture of Isomeric Dipeptides and their Diketopiperazines
Smith, Grant Gill,Baum, Rocky
, p. 2248 - 2255 (2007/10/02)
L-Alanylglycine (L-Ala-Gly), glycyl-L-alanine (Gly-L-Ala), and c-L-Ala-Gly were racemized at 120 deg C in aqueous phosphate-buffered solutions at pH 8.0, a pH value near maximum racemization.The kinetics were followed by regression analysis.The racemization of Ala-Gly and Gly-Ala closelly followed reversible first-order kinetics.The initial rate of racemisation of DKP was fast but soon slowed, likely because of hydrolysis to the dipeptides.The resulting rate was similar to that of the dipeptides.The observed racemization rate constans of the dipeptides and DKP were shown to be independent of the concentration of the peptides and the concetration of buffer.Component isolation studies using preparative TLC and chiral-phase GC analysis, coupled with computer analysis, showed an equilibrium existing between Ala-Gly, Gly-Ala, and DKP and the individual rates of racemization.At equilibrium, the mole fractions are as follows: Ala-Gly, 0.57; DKP, 0.22; Gly-Ala, 0.21.The rate constant for racemization of DKP was only 2 times that of Gly-Ala and 7 times the rate of Ala-Gly.Ala-Gly racemized 20 times and Gly-Ala 66 times faster than free alanine.The results support the influence of neighboring groups in the racemization of dipeptides.Factors that contribute to the rapid racemization (epimerization) are discussed.
Neighboring Residue Effects: Evidence for Intramolecular Assistance to Racemization or Epimerization of Dipeptide Residues
Smith, Grant Gill,Evans, Robert C.,Baum, Rocky
, p. 7327 - 7332 (2007/10/02)
Dipeptides, their methyl esters, diketopiperazines (DKP), and N-substituted derivatives were racemized at high temperatures (approximately 120 deg C) in aqueous phosphate buffered solutions at pH values close to pH of maximum racemization (approximately 8).The racemization of the dipeptides Ala-Gly and Gly-Ala followed reversible first-order kinetics.The initial rate of racemization of DKP was very fast but soon slowed down, supposedly due to hydrolysis.The resulting rate was similar to that of the dipeptides.Esters of dipeptides followed racemization patterns similar to DKP.The racemization rate constants of the dipeptides studied were shown to be independent of the concentration of the dipeptide and the concentration of buffer.A carboxy-terminal proline residue greatly increased the rate of racemization (epimerization) of the amino-terminal residue.Increasing the basicity of the N-terminal amino acid residue increased the rate of racemization (or epimerization) of the C-terminal residue unless the C-terminal was sterically hindered as the Ile and Val.Decreasing the basicity of the N-terminal amino acid residue decreased racemization or epimerization for nonhindered C-terminal amino acids.These results support the influence of neighboring groups in the racemization or epimerization of dipeptides.DKP formation is a competing reaction allowing racemization or epimerization in dipeptides.Dipeptide racemization or epimerization is proposed to be the result of combination of intramolecular base assistance and DKP formation.
Facile synthesis of (2R,3R)-phenylalanine-2,3-d2 and NMR study on deuterated gramicidin S1)
Tanimura,Kato,Waki,et al.
, p. 2193 - 2197 (2007/10/02)
(2R,3R)-Phenylalanine-2,3-d2 (D-Phe(*)) was synthesized through catalytic reduction of cyclo-(Z)-2,3-dehydrophenylalanyl-D-alanyl-) under an atmosphere of 2H2 and successive acid hydrolysis in the yield of 80% in high chiral induction. The D-Phe* thus obtained was used for synthesis of [D-Phe *4,4'] gramidicin S (GS*) gramidicin S (GS*). The 1H NMR spectrum of GS* in DMSO-d6 showed a sharp singlet at 2.98 ppm for the (3S)-proton of D-Phe* residue. It has been proposed that among rotamers of D-Phe aromatic side chain in GS the one with κ1 = 180° is predominant. The present observation provides sound evidence for assignments of D-Phe β-protons based on the proposal. (2R,3R)-phenylalanine-2,3-d//2 (d-Phe*) was synthesized through catalytic reduction of cyclo(-(Z)-2,3-dehydrophenylalanyl-D-alanyl-) under an atmosphere of **2H//2 and successive acid hydrolysis in the yield of 80% in high chiral induction. The D-Phe* thus obtained was used for synthesis of left bracket D-Phe***4**,**4** prime right bracket gramicidin S (GS*). The **1H NMR spectrum of GS* in DMSO-d//6 showed a sharp singlet at 2. 98 ppm for the (3S)-proton of D-Phe* residue. It has been proposed that among rotamers of D-Phe aromatic side chain in GS the one with // kappa //1 equals 180 degree is predominant. The present observation provides sound evidence for assignments of D-Phe beta -protons based on the proposal.
FACILE SYNTHESIS OF (2R,3R)-PHENYLALANINE -2,3-d2 AND ITS APPLICATION TO CONFORMATIONAL ANALYSIS OF GRAMICIDIN S
Tanimura, Kenjiro,Kato, Tetsuo,Waki, Michinori,Izumiya, Nobuo
, p. 3737 - 3740 (2007/10/02)
(2R,3R)-Phenylalanine-2,3-d2 was synthesized in a good yield through catalytic reduction of cyclo(-2,3-dehydrophenylalanyl-D-alanyl-) under an atmosphere of 2H2 and successive acid hydrolysis, and the amino acid was used t
