4818-08-0Relevant articles and documents
Phosphorus pentoxide for amide and peptide bond formation with minimal by-products
Erapalapati, Venkataramana,Hale, Umatai A.,Madhavan, Nandita
supporting information, (2019/11/21)
Phosphorus pentoxide and DMAP are used for amide bond formation from carboxylic acids and amines. Dipeptides and amides have been synthesized using this reagent in 42–77% yields and >99% ees. The protocol is attractive as it occurs at ambient temperature, the formation of organic by-products is minimal and the reagent can be readily quenched using water. Furthermore, excellent enantioselectivities are observed without the use of harsh triazole based additives.
Design and synthesis of novel hydroxypyridinone derivatives as potential tyrosinase inhibitors
Zhao, De-Yin,Zhang, Ming-Xia,Dong, Xiao-Wu,Hu, Yong-Zhou,Dai, Xiao-Yan,Wei, Xiaoyi,Hider, Robert C.,Zhang, Jin-Chao,Zhou, Tao
supporting information, p. 3103 - 3108 (2016/06/13)
Two groups of novel hydroxypyridinone derivatives 6(a-e) and 12(a-c), were designed as potential tyrosinase inhibitors, and synthesized using kojic acid as a starting material. The tyrosinase inhibitory activity of these two groups was demonstrated to be potent, especially compounds 6e and 12a, whose IC50 values for monophenolase activity were 1.95 μM and 2.79 μM, respectively. Both of these values are lower than that of kojic acid (IC50 = 12.50 μM). Compounds 6e and 12a were investigated for the inhibitory effect on diphenolase activity. The results showed that the inhibitory mechanism of these two compounds was reversible and that the inhibitory type was a competitive-uncompetitive mixed-type. The values of IC50 of 6e and 12a on the diphenolase activity of tyrosinase were determined to be 8.97 μM and 26.20 μM, respectively. The inhibitory constants (KI and KIS) of 6e were determined as 17.17 μM and 22.09 μM, respectively; and the KI and KIS values of 12a were 34.41 μM and 79.02 μM, respectively. Compound 6e showed a greater ability to reduce copper and a stronger copper chelating ability than kojic acid.
Synthesis of 2-(4,6-Dimethoxy-1,3,5-triazin-2-yloxyimino) derivatives: Application in solution peptide synthesis
Al-Warhi, Tarfah I.,AL-Hazimi, Hassan M.A.,El-Faham, Ayman,Albericio, Fernando
experimental part, p. 9403 - 9417 (2011/03/22)
A new class of 1,3,5-triazinyloxyimino derivatives were prepared, characterized and tested for reactivity in solution peptide synthesis. The new triazinyloxyimino derivatives failed to activate the carboxyl group during formation of peptide bonds, but gav
Sulfonate esters of 1-hydroxypyridin-2(1H)-one and ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma) as effective peptide coupling reagents to replace 1-hydroxybenzotriazole and 1-hydroxy-7-azabenzotriazole
Khattab, Sherine Nabil
experimental part, p. 501 - 506 (2010/09/06)
A new family of sulfonate ester-type coupling reagents is described which differs in its leaving group. The sulfonate ester coupling reagents ethyl 2-cyano-2-(naphthalen-2-ylsulfonyloxyimino)acetate (NpsOXY), and ethyl 2-cyano-2-(tosyloxyimino)acetate (Ts
Ethyl 2-Cyano-2-(hydroxyimino)acetate (Oxyma): An efficient and convenient additive used with tetramethylfluoroformamidinium hexafluorophosphate (TFFH) to replace 1-hydroxybenzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) during peptide synthesis
Khattab, Sherine N.
experimental part, p. 1374 - 1379 (2011/02/23)
The appropriateness of ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma) as a substitute for benzotriazole-based additives, for use in the TFFH approach for peptide synthesis, is discussed in terms of its capacity to control racemization, its coupling efficiency in difficult couplings either for stepwise or segment coupling in solution- and solid-phase coupling. In addition, Boc-based solution-phase peptide synthesis and its stability in the presence of growing peptide chains were studied. Oxyma displayed remarkable results in terms of racemization depression together with impressive coupling efficiency in both solution- and solid-phase synthesis. Furthermore, Oxyma suggests a lower risk of explosion than HOBt and HOAt.
Design, synthesis, and application of enantioselective coupling reagent with a traceless chiral auxiliary
Kolesinska, Beata,Kaminski, Zbigniew J.
supporting information; experimental part, p. 765 - 768 (2009/09/06)
(Chemical Equation Presented) Stable chiral N-triazinylbrucinium tetrafluoroborate enantioselectively activates racemic carboxylic acids yielding enantiomerically enriched amides, esters, and dipeptides with er from 8:92 to 0.5:99.5. Due to the departure
S-(2-Pyrimidinyl)- and S-(2-(4,6-dimethylpyrimidinyl))-1,1,3,3- tetramethylthiouronium hexafluorophosphates: Novel reagents for in situ peptide coupling
Garner, Philip,?e?eno?lu, ?zge,ümit Kaniskan
, p. 483 - 486 (2007/10/03)
Two new reagents for in situ peptide coupling based on the 2-mercaptopyrimidine core have been developed. The readily prepared thiouronium salts were found to promote both peptide and segment coupling efficiently with low racemization/epimerization levels
A flow reactor process for the synthesis of peptides utilizing immobilized reagents, scavengers and catch and release protocols
Baxendale, Ian R.,Ley, Steven V.,Smith, Christopher D.,Tranmer, Geoffrey K.
, p. 4835 - 4837 (2007/10/03)
A general flow process for the multi-step assembly of peptides has been developed and this procedure has been used to successfully construct a series of Boc, Cbz and Fmoc N-protected dipeptides in excellent yields and purities, including an extension of t
Asymmetric conjugate reductions with samarium diiodide: Asymmetric synthesis of (2S,3R)- And (2S,3S)-[2-2H,3-2H]-leucine-(S)- phenylalanine dipeptides and (2S,3R)-[2-2H,3-2H]- phenylalanine methyl ester
Davies, Stephen G.,Rodriguez-Solla, Humberto,Tamayo, Juan A.,Cowley, Andrew R.,Concellon, Carmen,Garner, A. Christopher,Parkes, Alastair L.,Smith, Andrew D.
, p. 1435 - 1447 (2007/10/03)
The highly diastereoselective samarium diiodide and D2O-promoted conjugate reduction of homochiral (E)- and (Z)-benzylidene and isobutylidene diketopiperazines (E)-5,7 and (Z)-6,8 has been demonstrated. This methodology allows the asymmetric synthesis of methyl (2S,3R)-dideuteriophenylalanine 27 in ≥95% de and >98% ee, and (2S,3R)- or (2S,3S)-dideuterioleucine-(S)- phenylalanine dipeptides 37 and 38 in moderate de, 66% and 74% respectively. A mechanism is proposed to account for this process. The Royal Society of Chemistry 2005.
Asymmetric synthesis of substituted 1-aminocyclopropane1-carboxylic acids via diketopiperazine methodology
Bunuel, Elena,Bull, Steven D.,Davies, Stephen G.,Garner, A. Christopher,Savory, Edward D.,Smith, Andrew D.,Vickers, Richard J.,Watkin, David J.
, p. 2531 - 2542 (2007/10/03)
Diketopiperazinespirocyclopropane 12 is prepared in > 98% d.e. via the conjugate addition of a phosphorus ylide to (6S)-N, N′-bis(p-methoxybenzyl)-3-methylenepiperazine-2,5-dione 2. Deprotection and hydrolysis of adduct 12 and subsequent peptide coupling demonstrate the applicability of this methodology to the asymmetric synthesis of 1-aminocyclopropane-1-carboxylic acids for incorporation into novel peptides. A model for the high level of diastereofacial selectivity observed in the cyclopropanation reaction is presented. A highly selective asymmetric approach (> 98% d.e.) to (S)-[2,2-2H 2]-1-aminocyclopropane-l-carboxylic acid 29 is also reported via a deuterated sulfur ylide addition to acceptor 2.
