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.
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.
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.
