1872-59-9Relevant articles and documents
Zn- And Cu-catalyzed coupling of tertiary alkyl bromides and oxalates to forge challenging C?O, C?S, and C?N bonds
Gong, Yuxin,Zhu, Zhaodong,Qian, Qun,Tong, Weiqi,Gong, Hegui
supporting information, p. 1005 - 1010 (2021/02/01)
We describe here the facile construction of sterically hindered tertiary alkyl ethers and thioethers via the Zn(OTf)2catalyzed coupling of alcohols/phenols with unactivated tertiary alkyl bromides and the Cu(OTf)2-catalyzed thiolation of unactivated tertiary alkyl oxalates with thiols. The present protocol represents one of the most effective unactivated tertiary C(sp3)? heteroatom bond-forming conditions via readily accessible Lewis acid catalysis that is surprisingly less developed.
Anthranilimide-based glycogen phosphorylase inhibitors for the treatment of Type 2 diabetes: 2. Optimization of serine and threonine ether amino acid residues
Sparks, Steven M.,Banker, Pierette,Bickett, David M.,Clancy, Daphne C.,Dickerson, Scott H.,Garrido, Dulce M.,Golden, Pamela L.,Peat, Andrew J.,Sheckler, Lauren R.,Tavares, Francis X.,Thomson, Stephen A.,Weiel, James E.
scheme or table, p. 981 - 985 (2009/08/15)
Optimization of the amino acid residue of a series of anthranilimide-based glycogen phosphorylase inhibitors is described leading to the identification of serine and threonine ether analogs. t-Butylthreonine analog 20 displayed potent in vitro inhibition of GPa, low potential for P450 inhibition, and excellent pharmacokinetic properties.
On the Preparation of β-Amino Acids from α-Amino Acids Using the Arndt-Eistert Reaction: Scope, Limitations and Stereoselectivity. Application to Carbohydrate Peptidation. Stereoselective α-Alkylations of Some β-Amino Acids
Podlech, Joachim,Seebach, Dieter
, p. 1217 - 1228 (2007/10/02)
The Arndt-Eistert homologation of α-amino acids was studied to determine the stereoselectivity in this reaction by chromatographic up-to-date analytical methods.While carbamate-protected phenylglycine was transformed to the corresponding β-amino acid methyl ester with a stereoselectivity of only 9:1, all other tested amino acid derivatives (Ala, Phe, Ser, Orn, tert-Leu and perhydro-azepine-2-carboxylic acid, suitably protected) were homologated with full retention of configuration (products 9-17).The intermediate diazo ketones 1-8 were purified and characterized by their NMR spectra.When nucleophiles derived from partially protected sugars were present during decomposition of the diazo ketones (derived from amino acids or dipeptides), a strong dependence of the yield (products 21-24) on the degree of steric hindrance of the nucleophilic OH group was observed.Two of the β-amino acids obtained from the homologation reaction were transformed to α-substituted (25-27, 31, 32) and α,α-disubstituted β-amino acid derivatives (28, 29) with excellent selctivities (in most cases, a single diastereoisomer was obtained). - Key Words: β-Amino acids, α-branched/Glycopeptides