55715-03-2Relevant articles and documents
Synthesis of peptide-N-alkylamides on a new PS-TTEGDA polymer support using photolabile anchoring group
Kumar,Pillai, V. N. Rajasekharan
, p. 10437 - 10446 (1999)
Peptide-N-alkylamides were synthesised on a new highly solvating copolymer of 4% tetraethyleneglycol diacrylate-cross-linked polystyrene (PS- TTEGDA) support. The polymer was synthesised by suspension polymerisation using a free radical initiator. The synthesis of C-terminal peptide-N- alkylamide involve prior incorporation of a photolabile linker, 3-nitro-4- bromo-methylbenzoic acid to the aminomethylated support. The N-alkylamino group act as an anchoring group for the peptide as well as a latent function for the C-terminal modification of the attached peptide. Irradiation of the peptide-resin with 350 nm light in TFE/DCM resulted in the release of peptide-N-alkylamides. Synthetic utility of the new support was demonstrated by the synthesis of Boc-amino acid-N-alkylamides and C-terminal peptide-N- alkyl amides in 75-80% yields and with high purity.
A responsive hyperbranched polymer not only can self-immolate but also can self-cross-link
Yu, Zhi-Qiang,Xu, Xiao-Man,Hong, Chun-Yan,Wu, De-Cheng,You, Ye-Zi
, p. 4136 - 4143 (2014)
Though many responsive polymers have been prepared, none of them can both self-immolate and self-cross-link via responding to the changes of the environment. Here, we introduce a new responsive hyperbranched polymer, which not only can self-immolate but also can self-cross-link via responding to the external stimuli. Moreover, the obtained polymer can form a bioreducible nanogel in its aqueous solution simply via heating, and the formed nanogel can self-immolate via UV irradiation.
Highly Enantioselective Synthesis of Indazoles with a C3-Quaternary Chiral Center Using CuH Catalysis
Ye, Yuxuan,Kevlishvili, Ilia,Feng, Sheng,Liu, Peng,Buchwald, Stephen L.
supporting information, p. 10550 - 10556 (2020/07/27)
C3-substituted 1H-indazoles are useful and important substructures in many pharmaceuticals. Methods for direct C3-functionalization of indazoles are relatively rare, compared to reactions developed for the more nucleophilic N1 and N2 positions. Herein, we report a highly C3-selective allylation reaction of 1H-N-(benzoyloxy)indazoles using CuH catalysis. A variety of C3-allyl 1H-indazoles with quaternary stereocenters were efficiently prepared with high levels of enantioselectivity. Density functional theory (DFT) calculations were performed to explain the reactivity differences between indazole and indole electrophiles, the latter of which was used in our previously reported method. The calculations suggest that the indazole allylation reaction proceeds through an enantioselectivity-determining six-membered Zimmerman-Traxler-type transition state, rather than an oxidative addition/reductive elimination sequence, as we proposed in the case of indole alkylation. The enantioselectivity of the reaction is governed by both ligand-substrate steric interactions and steric repulsions involving the pseudoaxial substituent in the six-membered allylation transition state.
A Three-Dimensional Orthogonal Protection Scheme for Solid-Phase Peptide Synthesis under Mild Conditions
Barany, George,Albericio, Fernando
, p. 4936 - 4942 (2007/10/02)
Several Nα-dithiasuccinoyl (Dts) amino acids (1) were esterified, by use of N,N'-dicyclohexylcarbodiimide (DCC) and without racemization, to tert-butyl 4-(hydroxymethyl)-3-nitrobenzoate (8).The resultant handle derivatives 4 were treated with trifluoroacetic acid to yield crystalline 4-(Nα-Dts-aminoacyloxymethyl)-3-nitrobenzoic acids (3), which were quantitatively incorporated onto aminomethylcopoly(styrene-1percent divinylbenzene)-resins by DCC-mediated couplings to give the starting point for stepwise solid-phase synthesis of peptides anchored as o-nitrobenzyl (ONb) esters.Assembly of the protected leucine-enkephalin-resin derivative Dts-Tyr(t-Bu)-Gly-Gly-Phe-Leu-ONb-resin (2) was achieved from the appropiate Dts-amino acids by a highly efficient protocol.By carrying out, in each conceivable order, either in solution or on the solid phase, one two, or all three of the following orthogonal treatments , the common resin-bound intermediate 2 became the source of four partially or fully deblocked leucine-enkephalin derivatives.These four, namely Dts-Tyr(t-Bu)-Gly-Gly-Phe-Leu-OH, Dts-Tyr-Gly-Gly-Phe-Leu-OH, H-Tyr(t-Bu)-Gly-Gly-Phe-Leu-OH, and H-Tyr-Gly-Gly-Phe-Leu-OH, were each obtained pure in good yields and were characterized by amino acid composition, HPLC, 300-MHz 1H NMR, and fast atom bombardment mass spectrometry.The protected dipeptidyl sequence Prot-D-Val-L-Pro-ONb-resin was assembled with three different Nα-amino protecting groups and exposed to the recommended deblocking reagents.Loss of chains from the resin by diketopiperazine formation was very rapid with Prot=9-fluorenylmethoxycarbonyl (Fmoc) and also substantial with Prot=tert-butoxycarbonyl (Boc), but rather negligible wit h Prot=Dts.Thus, these experiments demonstrate the feasibility and benefits of a mild three-dimensional orthogonal protection scheme based on Dts for Nα-amino protection, tert-butyl derivatives for side chains, and o-nitrobenzyl esters for anchoring.
3-Nitro-4-bromomethyl benzoic acid
-
, (2008/06/13)
The invention is addressed to the preparation of 3-nitro-4-bromomethyl benzoic acid, as a new compound from which 3-nitro-4-bromomethyl benzoyl amide polystyrene resin can be prepared for solid synthesis of protected peptide acids and amides and separation thereof without cleavage of acid labile protecting groups or decomposition of aromatic acid groups and from which purified polypeptides can be formed.
New, Easily Removable Poly(ethylene glycol) Supports for the Liquid-Phase Method of Peptide Synthesis
Pillai, V. N. Rajasekharan,Mutter, Manfred,Bayer, Ernst,Gatfield, Ian
, p. 5364 - 5370 (2007/10/02)
Poly(ethylene glycol) (PEG) was derivatized with a number of acid-cleavable and photocleavable anchoring groups in order to test the applicability of these derivatives as supports in liquid-phase peptide synthesis.PEG was subjected to rapid and quantitati
