17350-17-3Relevant articles and documents
Combining prolinamides with 2-pyrrolidinone: Novel organocatalysts for the asymmetric aldol reaction
Vlasserou, Ismini,Sfetsa, Maria,Gerokonstantis, Dimitrios-Triantafyllos,Kokotos, Christoforos G.,Moutevelis-Minakakis, Panagiota
, p. 2338 - 2349 (2018/04/06)
Peptides and especially prolinamides have been identified as excellent organocatalysts for the aldol reaction. The combination of prolinamides with derivatives bearing the 2-pyrrolidinone scaffold, deriving from pyroglutamic acid, led to the identification of novel organocatalysts for the intermolecular asymmetric aldol reaction. The new hybrids were tested both in organic and aqueous media. Among the compounds tested, 22 afforded the best results in petroleum ether, while 25 afforded the products in brine in high yields and selectivities. Then, various ketones and aldehydes were utilized and the products of the aldol reaction were obtained in high yields (up to 100%) with excellent diastereo- (up to 97:3 dr) and enantioselectivities (up to 99% ee).
Proline dipeptides containing fluorine moieties as oganocatalysts for the asymmetric aldol reaction
Ahmetlli, Ardiol,Spiliopoulou, Nikoleta,Magi-Oikonomopoulou, Angeliki,Gerokonstantis, Dimitrios-Triantaffylos,Moutevelis-Minakakis, Panagiota,Kokotos, Christoforos G.
, p. 5987 - 5995 (2018/09/21)
A series of dipeptide analogues consisting of proline, phenylalanine and aniline- or phenol-fluorine derivatives were synthesized. Their catalytic ability was evaluated in the intermolecular asymmetric aldol reaction, both in organic and aqueous media. Aniline-fluorine derivatives proved to be superior and the best results were obtained, when 2-CF3 aniline was employed. A diverse substrate scope consisting of both aromatic and aliphatic aldehydes, as well as different ketones was demonstrated, where aromatic aldehydes afforded products in high yields (up to 100%) with excellent diastereo- (up to 95:5) and enantioselectivities (up to 97%), whereas the aliphatic aldehydes afforded also excellent selectivities, but relatively low yield. A simple addition of fluorine to a dipeptide analogue affords organocatalysts with new interesting properties that can catalyze the aldol reaction more efficiently.
Direct Hydroxylation of Benzene to Phenol by Cytochrome P450BM3 Triggered by Amino Acid Derivatives
Shoji, Osami,Yanagisawa, Sota,Stanfield, Joshua Kyle,Suzuki, Kazuto,Cong, Zhiqi,Sugimoto, Hiroshi,Shiro, Yoshitsugu,Watanabe, Yoshihito
supporting information, p. 10324 - 10329 (2017/08/22)
The selective hydroxylation of benzene to phenol, without the formation of side products resulting from overoxidation, is catalyzed by cytochrome P450BM3 with the assistance of amino acid derivatives as decoy molecules. The catalytic turnover rate and the total turnover number reached 259 min?1 P450BM3?1 and 40 200 P450BM3?1 when N-heptyl-l-proline modified with l-phenylalanine (C7-l-Pro-l-Phe) was used as the decoy molecule. This work shows that amino acid derivatives with a totally different structure from fatty acids can be used as decoy molecules for aromatic hydroxylation by wild-type P450BM3. This method for non-native substrate hydroxylation by wild-type P450BM3 has the potential to expand the utility of P450BM3 for biotransformations.
α-N-Protected dipeptide acids: A simple and efficient synthesis via the easily accessible mixed anhydride method using free amino acids in DMSO and tetrabutylammonium hydroxide
Verardo,Gorassini
, p. 315 - 324 (2013/06/05)
The importance of dipeptides both in medicinal and pharmacological fields is well documented and many efforts have been made to find simple and efficient methods for their synthesis. For this reason, we have investigated the synthesis of α-N-protected dipeptide acids by reacting the easily accessible mixed anhydride of α-N-protected amino acids with free amino acids under different reaction conditions. The combination of TBA-OH and DMSO has been found to be the best to overcome the low solubility of amino acids in organic solvents. Under these experimental conditions, the homogeneous phase condensation reaction occurs rapidly and without detectable epimerization. The present method is also applicable to side-chain unprotected Tyr, Trp, Glu, and Asp but not Lys. This latter residue is able to engage two molecules of mixed anhydride giving the corresponding isotripeptide. Moreover, the applicability of this protocol for the synthesis of tri- and tetrapeptides has been tested. This approach reduces the need for protecting groups, is cost effective, scalable, and yields dipeptide acids that can be used as building blocks in the synthesis of larger peptides.
Novel prolinamide-ureas as organocatalysts for the asymmetric aldol reaction
Revelou, Panagiota,Kokotos, Christoforos G.,Moutevelis-Minakakis, Panagiota
, p. 8732 - 8738 (2012/11/13)
Among the various versions of the aldol reaction, the enantioselective reaction between cyclic ketones and aldehydes constitutes a typical reaction model for the evaluation of novel organocatalysts. A multifunctional organocatalyst consisting of a prolinamide moiety, a gem diamine unit and a urea group was successfully employed in this asymmetric transformation. The products of the reaction between various ketones and aldehydes were obtained in high yields (up to 98%) with excellent diastereo- (up to >98:2 dr) and enantioselectivities (up to 99% ee).
L-proline-catalyzed asymmetric michael addition of 2-oxindoles to enones: A convenient access to oxindoles with a quaternary stereocenter
Freund, Matthias H.,Tsogoeva, Svetlana B.
, p. 503 - 507 (2011/04/18)
A new organocatalytic approach for 1,4-conjugate addition of 2-oxindoles to α,β-unsaturated ketones using the combination of readily available and nonexpensive l-proline and achiral trans-2,5-dimethylpiperazine as catalytic system is provided. The reaction results in oxindole derivatives with vicinal quaternary and tertiary carbon centers in up to 99% yield and 91% ee. Georg Thieme Verlag Stuttgart.
Synthesis of proline-derived dipeptides and their catalytic enantioselective direct aldol reactions: Catalyst, solvent, additive and temperature effects
Chen,Sung,Sung, Kuangsen
experimental part, p. 839 - 845 (2010/08/06)
A series of dipeptides of l-proline-l-amino acid and l-proline-d-amino acid were synthesized to evaluate the catalytic effect for asymmetric direct aldol reactions. In the direct aldol reaction, a catalyst of l-proline-l-amino acid achieves better enantioselectivity than the corresponding l-proline-d-amino acid catalyst. Solubility of the dipeptide catalysts in the solvents is a key point for achieving a better yield of the direct aldol reaction, while hydrogen bonding of solvent does not play an important role in attaining better enantioselectivity and yield. Yield and enantioselectivity of the direct aldol reaction in water were improved by NMM and SDS additives, but the results that were done in plain DMSO were even better.
Efficient peptide coupling involving sterically hindered amino acids
Katritzky, Alan R.,Todadze, Ekaterina,Angrish, Parul,Draghici, Bogdan
, p. 5794 - 5801 (2008/02/09)
(Chemical Equation Presented) Hindered amino acids have been introduced into peptide chains by coupling N-(Cbz- and Fmoc-α-aminoacyl) benzotriazoles with amino acids, wherein at least one of the components was sterically hindered, to provide compounds 3a-e, (3c +3 c′), 5a-d, (5a + 5a′), 6a-c, (6b + 6b′), 8a-c, 9a-e, 10a-d, and (10a + 10a′) in isolated yields of 41-95% with complete retention of chirality as evidenced by NMR and HPLC analysis. The benzotriazole activation methodology is a new route for the synthesis of sterically hindered peptides. (Note: compound numbers written within brackets represent diastereomeric mixtures or racemates; compound numbers without brackets represent enantiomers.)
Small peptides catalyze highly enantioselective direct aldol reactions of aldehydes with hydroxyacetone: Unprecedented regiocontrol in aqueous media
Tang, Zhuo,Yang, Zhi-Hua,Cun, Lin-Feng,Gong, Liu-Zhu,Mi, Ai-Qiao,Jiang, Yao-Zhong
, p. 2285 - 2287 (2007/10/03)
L-Proline-based small peptides have been developed as efficient catalysts for the asymmetric direct aldol reactions of hydroxyacetone with aldehydes. Chiral 1,4-diols 7, which are disfavored products in similar aldol reactions catalyzed by either aldolases or t-proline, were obtained in high yields and enantioselectivities of up to 96% ee with peptides 3 and 4 in aqueous media.
Tri- and tetrapeptide analogues of kinins as potential renal vasodilators
Pfeiffer,Chambers,Hilbert,Woodward,Ackerman
, p. 325 - 341 (2007/10/02)
Tri- and tetrapeptide analogues were synthesized and evaluated as renal vasodilators. These peptides were prepared by standard coupling reactions which also provided good yields with hindered α-methyl amino acid derivatives. Preliminary evidence of renal vasodilator activity was determined in anesthetized dogs by measuring the effects on renal blood flow and calculating the accompanying changes in renal vascular resistance. The most potent compounds contained, in their structure, the L-prolyl-DL-α-methylphenylalanyl-L-arginine and L-prolyl-DL-α-methyl-phenyalanylglycyl-L-proline arrays. Substitution on the N-terminal proline with 4-phenylbutyryl and 4-(4-hydroxyphenyl)butyryl side chains produced enhanced renal vasodilator activity and, in certain cases, selectivity for the renal vasculature.