96-86-6Relevant articles and documents
Effective C5-Arylation of Peptide-Integrated Oxazoles: Almazole D
Oberheide, Ansgar,Arndt, Hans-Dieter
supporting information, p. 1132 - 1136 (2020/12/22)
An efficient functionalization approach of oxazoles by using Pd-catalyzed cross-coupling reactions is reported. Oxazolone formation and subsequent sulfamoylation in situ are facilitated by employing N,N-diethylsulfamoyl imidazolium triflate. Cross-couplings provide both oxazole-arenes and oxazole-heteroarenes and were compatible with sensitive and epimerization-prone substrates, as exemplified by the total synthesis of the natural product almazole D. (Figure presented.).
Transformation of Racemic Azlactones into Enantioenriched Dihydropyrroles and Lactones Enabled by Hydrogen-Bond Organocatalysis
?abka, Matej,Kocian, Adrián,Bilka, Stanislav,Andrej?ák, Samuel,?ebesta, Radovan
, p. 6077 - 6087 (2019/09/12)
Azlactones, a potent building block for the synthesis of complex molecules, have been explored in an organocatalytic Mannich reaction with protected imines. In this study, azlactones containing a propargyl substituent were employed for the first time in organocatalysis so far. The catalytically active species responsible for high enantioselectivity with substrate containing such a small linear substituent is assembled in situ from a bifunctional thiourea, prone to dimerization, and an organic acid, as evidenced by DOSY NMR. The resulting α,β-diamino acid derivatives were subjected to further derivatization: as an example, gold-catalyzed intramolecular hydroamination of alkynes gave chiral spirocyclic dihydropyrrole. Alternatively, related squaramide catalyst enabled a Mannich reaction of azlactones with N-aryl or alkyl glyoxylate imines. Reduction of these adducts gave access to 2,3-diaminobutyrolactones or 2,3-diamino-1,4-diol with a tertiary and a quaternary stereocenter.
Synthesis of new ligands for targeting the S1P1 receptor
Schilson, Stefanie S.,Keul, Petra,Shaikh, Rizwan S.,Sch?fers, Michael,Levkau, Bodo,Haufe, Günter
supporting information, p. 1011 - 1026 (2015/03/04)
Sphingosine-1-phosphate (S1P) influences various fundamental biological processes by interacting with a family of five G protein-coupled receptors (S1P1-5). FTY720, a sphingosine analogue, which was approved for treatment of relapsing forms of multiple sclerosis, is phosphorylated in vivo and acts as an agonist of four of the five S1P receptor subtypes. Starting from these lead structures we developed new agonists for the S1P1 receptor. The biological activity was tested in vivo and promising ligands were fluorinated at different positions to identify candidates for positron emission tomography (PET) imaging after [18F]-labelling. The radioligands shall enable the imaging of S1P1 receptor expression in vivo and thus may serve as novel imaging markers of S1P-related diseases.
