- CuI-promoted one-pot synthesis of N-boc protected β-ketotriazole amino acids: Application in the synthesis of new class of dipeptidomimetics
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One-pot click chemistry of Nα-Boc-bromomethylketones, NaN3 and propiolic acid affords N-Boc protected 1,4- disubstituted 1,2,3-β-ketotriazole acids in good to excellent yield. The use of CuI as catalyst and DMSO as solvent leads the click react
- Vishwanathaa,Narendra,Sureshbabu, Vommina V.
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experimental part
p. 308 - 314
(2012/07/17)
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- Design and synthesis of 6-substituted amino-4-oxa-1-azabicyclo[3,2,0]heptan-7-one derivatives as cysteine proteases inhibitors
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A series of 6-substituted amino-4-oxa-1-azabicyclo[3,2,0]heptan-7-one compounds was designed and synthesized as a new class of inhibitors for cysteine proteases cathepsins B, L, K, and S. One compound (5S,6S)-6-(N-benzyloxycarbonyl-L-phenylalanyl) amino-4
- Zhou, Nian E.,Guo, Deqi,Kaleta, Jadwiga,Purisima, Enrico,Menard, Robert,Micetich, Ronald G.,Singh, Rajeshwar
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p. 3413 - 3415
(2007/10/03)
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- Coupling N-Methylated Amino Acids Using PyBroP and PyCloP Halogenophosphonium Salts: Mechanism and Fields of Application
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PyBroP (1) and PyCloP (2), two halotripyrrolidinophosphonium hexafluorophosphates, are peptidecoupling reagents highly efficient for coupling N-methylated amino esters, in contrast with PyBOP (3), the hydroxybenzotriazolyl analogue.These halogenophosphonium salts 1 and 2 are convenient (one-pot reactions) stable solids soluble in conventional solvents.Use of them gave an excellent peptide yield with essentially no epimerization.Activation with these reagents probably involves the formation of an (acyloxy)phosphonium, as shown in the case of 2,4,6-trimethylbenzoic acid activation.In the case of reagents 1 and 2, oxazolone and/or a symmetrical anhydride were intermediates which were rapidly aminolyzed.In contrast, the benzotriazolyl ester intermediate which was formed with PyBOP (3) was poorly reactive with N-methylated amino esters.PyBroP (1) and PyCloP (2) were less efficient in the coupling of some Boc-amino acids because of N-carboxyanhydride formation; this was particularly the case when Boc-Val-OH or Boc-MeVal-OH was coupled with MeVal-OMe.
- Coste, Jacques,Frerot, Eric,Jouin, Patrick
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p. 2437 - 2446
(2007/10/02)
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- USE OF POLYMERIC ACTIVATED ESTERS BASED ON 1-HYDROXYBENZOTRIAZOLE IN PEPTIDE SYNTHESIS
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A further study was made of the possibility of using polymeric activated esters based on 1-hydroxybenzotriazole in the peptide synthesis as illustrated by the synthesis of the model dipeptides N-tert-butyloxycarbonylalanylphenylalanine methyl ester and N-benzyloxycarbonylvalylglycine methyl ester.A series of negative qualities, which make their use difficult, were noticed in these ethers.A more convenient modification of the already known method for the production of the esters is proposed.In this method 3-nitro-4-chlorobenzyl alcohol, which is the key product forthe production of 1-hydroxybenzotriazole fixed on a polystyrene matrix, can be synthesized with a high yield and a high degree of purity by the reduction of the corresponding aldehyde with aluminum isopropoxide.
- Grigor'ev, E. I.,Zhil'tsov, O. S.A
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p. 1774 - 1777
(2007/10/02)
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- A Convenient Synthesis of Peptide Using Oxallates
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The equimolar reactions of N-protected amino acids , amino acids or amino acid esters with oxallates (1a-1e) having active ester groups in the presence of pyridine in acetonitrile afforded the corresponding dipeptides via active esters in good yields.
- Takeda, Kazuyoshi,Sawada, Izumi,Suzuki, Akira,Ogura, Haruo
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p. 4451 - 4454
(2007/10/02)
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