214475-40-8Relevant academic research and scientific papers
Structural insight into the aggregation of l-prolyl dipeptides and its effect on organocatalytic performance
Berdugo, Cristina,Escuder, Beatriu,Miravet, Juan F.
, p. 592 - 600 (2014)
NMR and organocatalytic studies of four dipeptides derived from l-proline are described. Results indicate that important conformational changes around the catalytic l-proline moiety are observed for free dipeptides upon changing the adjacent amino acid. Also, an aggregation process is detected as the concentration increases. The self-association of the dipeptides has been fitted to a cooperative binding model. All the compounds have been assayed as catalysts for the conjugated addition of cyclohexanone to trans-β-nitrostyrene in toluene. In agreement with the structural studies, noticeable changes in the catalytic performance are detected upon changing the catalyst concentration, as the catalyst is activated by self-aggregation. This journal is
Mechanistic insight into the lability of the benzyloxycarbonyl (Z) group in N-protected peptides under mild basic conditions
Tena-Solsona, Marta,Angulo-Pachon, Cesar A.,Escuder, Beatriu,Miravet, Juan F.
, p. 3372 - 3378 (2014/06/09)
An unexpected lability of the benzyloxycarbonyl (Z) protecting group under mild basic conditions at room temperature is explained by a mechanism based on anchimeric assistance. It is found that the vicinal amide group stabilises the tetrahedral intermediate formed after nucleophilic addition of hydroxide to the carbonyl of the Z group. This effect operates in N-protected tripeptides and tetrapeptides but Z-protected dipeptides are stable under the same conditions due to blockage of the vicinal amide NH by intramolecular H-bonding with the terminal carboxylate moiety. Copyright
Synthesis of chiral tropopodands having l-amino acid moieties and ability of their metal complexes as an asymmetric catalyst
Sato, Ohki,Koshiba, Yusuke,Sagara, Satoshi,Okada, Katsuyoshi
, p. 529 - 533 (2007/10/03)
Optical active tropopodans (10 and 11) having neutral l-amino acids and l-histidine moieties were synthesized. Within their metal complexes, Pd complexes of histidine-tropopodands (11b and 11c) bearing bulky amide moieties showed good ability as an asymmetric catalyst in conjugate addition.
Nickel complexes from α-amino amides as efficient catalysts for the enantioselective Et2Zn addition to benzaldehyde
Burguete, M. Isabel,Collado, Manuel,Escorihuela, Jorge,Galindo, Francisco,García-Verdugo, Eduardo,Luis, Santiago V.,Vicent, María J.
, p. 6891 - 6894 (2007/10/03)
Ni2+ complexes derived from simple α-amino amides catalyze very efficiently the addition of Et2Zn to benzaldehyde, giving (S)-1-phenylethanol as the major isomer in most cases (94% yield, 97% ee for R=Bn). The nature of the substituent on the amide nitrogen atom seems to play a key role in determining the asymmetric induction observed.
Aryl hydrazides as linkers for solid phase synthesis which are cleavable under mild oxidative conditions
Millington, Christopher R.,Quarrell, Rachel,Lowe, Gordon
, p. 7201 - 7204 (2007/10/03)
We have developed an acid/base stable aryl hydrazide linker which is readily coupled to solid phase resins. Cleavage is specific and facile, requiring a copper (II) catalyst, base and a nucleophile to proceed. The conditions are compatible with all 20 proteinogenic amino acids and quantitative cleavage is achieved within 2 hours at 20°C to give peptides with C-terminal acid, amide or ester functionalities. Aryl hydrazides also offer scope as simple 'traceless' linkers.
