17585-59-0Relevant articles and documents
A comparative study of two polymorphs of l-aspartic acid hydrochloride
Benali-Cherif, Rim,Takouachet, Radhwane,Bendeif, El-Eulmi,Benali-Cherif, Nourredine
, p. 689 - 692 (2014)
Two polymorphs of l-aspartic acid hydrochloride, C4H 8NO4+ Cl-, were obtained from the same aqueous solution. Their crystal structures have been determined from single-crystal data collected at 100 K. The crystal structures revealed three- and two-dimensional hydrogen-bonding networks for the triclinic and orthorhombic polymorphs, respectively. The cations and anions are connected to one another via N-H...Cl and O-H...Cl interactions and form alternating cation-anion layer-like structures. The two polymorphs share common structural features; however, the conformations of the l-aspartate cations and the crystal packings are different. Furthermore, the molecular packing of the orthorhombic polymorph contains more interesting interactions which seems to be a favourable factor for more efficient charge transfer within the crystal.
Solvent-freeN-Boc deprotection byex situgeneration of hydrogen chloride gas
De Borggraeve, Wim M.,Gilles, Philippe,Van Mileghem, Seger,Verschueren, Rik H.
supporting information, p. 5782 - 5787 (2021/07/12)
An efficient, scalable and sustainable method for the quantitative deprotection of thetert-butyl carbamate (N-Boc) protecting group is described, using down to near-stoichiometric amounts of hydrogen chloride gas in solvent-free conditions. We demonstrate theex situgeneration of hydrogen chloride gas from sodium chloride and sulfuric acid in a two-chamber reactor, introducing a straightforward method for controlled and stoichiometric release of HCl gas. The solvent-free conditions allow deprotection of a wide variety ofN-Boc derivatives to obtain the hydrochloride salts in quantitative yields. The procedure obviates the need for any work-up or purification steps providing an uncomplicated green alternative to standard methods. Due to the solvent-free, anhydrous conditions, this method shows high tolerance towards acid sensitive functional groups and furnishes expanded functional group orthogonality.
3-Triphenylphosphonio-2,5-piperazinediones as new chiral glycine cation equivalents
Gorewoda, Tadeusz,Mazurkiewicz, Roman,Simka, Wojciech,Mloston, Grzegorz,Schroeder, Grzegorz,Kubicki, MacIej,Kuznik, Nikodem
experimental part, p. 823 - 833 (2011/09/12)
3-Triphenylphosphonio-2,5-piperazinediones were effectively synthesized from homochiral valine or proline via Boc-Val-Gly-OMe, Boc-Pro-Gly-OMe or Cbz-Pro-Gly-OMe. Retention of configuration of the primary stereogenic center of the valine and proline moieties was observed. Diastereoselective nucleophilic substitution of the triphenylphosphonium group in 2,5-piperazinediones with S-, N-, P- and C-nucleophiles was observed. The configuration of the substitution products was assigned either by their hydrolysis and decarboxylation or based on the analysis of the H-C(3)-N-H coupling constants of 3-substituted-2,5- piperazinediones derived from proline. The trans-stereoselectivity was predominant in reactions of 3-triphenylphosphonio-1,6-trimethylene-2,5- piperazinediones with the nucleophiles investigated. The stereodifferentiating ability of the proline moiety is much stronger than that of the valine unit and allowed nucleophilic α-functionalization of the glycine moiety with good to excellent diastereoselectivity.
Neopetrosiamides, peptides from the marine sponge Neopetrosia sp. that inhibit amoeboid invasion by human tumor cells
Williams, David E.,Austin, Pamela,Diaz-Marrero, Ana R.,Van Soest, Rob,Matainaho, Teatulohi,Roskelley, Calvin D.,Roberge, Michel,Andersen, Raymond J.
, p. 4173 - 4176 (2007/10/03)
(Chemical Equation Presented) Neopetrosiamdes A (1) and B (2), two diastereomeric tricyclic peptides that inhibit amoeboid invasion of human tumor cells, have been isolated from the marine sponge Neopetrosia sp. collected in Papua New Guinea. The structures of the neopetrosiamides were elucidated by analysis of MS and NMR data and confirmed by chemical degradation.