Exceptionally small supramolecular hydrogelators based on aromatic–aromatic interactions

• Junfeng Shi,
• Yuan Gao,
• Zhimou Yang and
• Bing Xu

Beilstein J. Org. Chem. 2011, 7, 167–172, doi:10.3762/bjoc.7.23

• less explored. We have shown that aromatic–aromatic interactions induce the self-assembly of glycopeptides [30] or pentapeptidic derivatives [31] in water to form nanofibers and supramolecular hydrogels. These results, together with the supramolecular hydrogelators made from dipeptide conjugates with

Oxalyl retro-peptide gelators. Synthesis, gelation properties and stereochemical effects

• Janja Makarević,
• Milan Jokić,
• Leo Frkanec,
• Vesna Čaplar,
• Nataša Šijaković Vujičić and
• Mladen Žinić

Beilstein J. Org. Chem. 2010, 6, 945–959, doi:10.3762/bjoc.6.106

• characteristics of gels formed by chiral bis(dipeptide)oxalamides. Structurally, such gelators belong to the group of retro-peptides, which have been intensively studied as peptidomimetics due to their higher proteolytic stability and bioavailability compared to natural counterparts [44][45][46][47]. Despite very

• (dipeptide)oxalamides was prepared as outlined in Scheme 1. The synthesis and analytical characterization of the prepared compounds are collected in the Supporting Information. Two sets of bis(dipeptide)oxalamides were prepared: the first incorporating a single amino acid and variable terminal groups such as

• fibers capable of networking. Terminal dimethyl ester retro-dipeptides In the previously studied series of bis(amino acid)oxalamide gelators transformation of terminal carboxylic acid groups into methyl esters resulted in the complete loss of gelation ability [59]. In the retro-dipeptide series the

Synthesis of a novel analogue of DPP-4 inhibitor Alogliptin: Introduction of a spirocyclic moiety on the piperidine ring

• Arumugam Kodimuthali,
• Padala Lakshmi Prasunamba and
• Manojit Pal

Beilstein J. Org. Chem. 2010, 6, No. 71, doi:10.3762/bjoc.6.71

• dipeptidyl peptidase-4 (DPP-4; CD26; E.C. 3.4.14.5) by small molecules has emerged as one of the key approaches for the treatment of type-2 diabetes [1][2][3][4][5]. DPP-4, a member of the prolyl oligopeptidase family of serine protease, cleaves the N-terminal dipeptide from peptides with proline or alanine

Synthesis of glycosylated β³-homo-threonine conjugates for mucin-like glycopeptide antigen analogues

• Florian Karch and
• Anja Hoffmann-Röder

Beilstein J. Org. Chem. 2010, 6, No. 47, doi:10.3762/bjoc.6.47

• , glycosylation of the corresponding dipeptide precursor Fmoc-β3hThr(OH)-Ala-OBn failed completely. Therefore we encountered the strategy of Arndt–Eistert homologation in the synthesis of the target Fmoc-β3hThr(αAc3GalNAc) and Fmoc-β3hThr(β(Ac4Gal(1–3))α(Ac3GalNAc)) conjugates 2a and 4, respectively, as reported

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

• Ana Maria Castilla,
• M. Morgan Conn and
• Pablo Ballester

Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5

• present in the diamide series, selecting the α-amino acid-related hydrogen-bonding functionality. Only one of the two cyclic receptors shows modest signs of enantioselectivity and moderate diastereoselectivity in the recognition of the enantiomers and diastereoisomers of the Ala-Ala dipeptide (ΔΔG01 (DD

• dipeptide, the common target for the vancomycin antibiotics. This group of antibiotics is active against certain aerobic and anaerobic Gram-positive bacteria, and has been used for many years as treatment of last resort in clinical wards [2][3][4]. However, vancomycin resistance has recently been identified

• among clinical isolates of several Gram-positive species [5][6][7][8]. Therefore, although many examples already exist in the literature [9][10], the design and synthesis of new synthetic receptors for this dipeptide is still a relevant endeavor not only in terms of understanding the interactions that

The first preparative solution phase synthesis of melanotan II

• Vladimir V. Ryakhovsky,
• Georgy A. Khachiyan,
• Nina F. Kosovova,
• Elena F. Isamiddinova and
• Andrey S. Ivanov

Beilstein J. Org. Chem. 2008, 4, No. 39, doi:10.3762/bjoc.4.39

• melanotan II molecule was started by coupling of Nε-Boc-lysinamide (3) with Nα-benzyloxycarbonyltryptophan pentafluorophenyl ester to yield dipeptide 4 (Scheme 1). Cleavage of the Z protecting group afforded dipeptide 5. Reaction of arginine with Nα -Z-D-phenylalanine pentafluorophenyl ester led to a

• protected dipeptide 6. Since arginine exists in DMF solution in zwitterionic form, no protection for highly basic guanidine group was required. The guanidine group of arginine was deactivated for the next 4 steps by adding an equivalent of HCl (dioxane solution) to dipeptide 6. The resulting salt was

• coupled with another dipeptide 5 using a combination of N,N′-dicyclohexylcarbodiimide (DCC) and N-hydroxynorbornene-2,3-dicarboximide (HONb) to yield a tetrapeptide product 7. The latter was subjected to catalytic hydrogenolysis leading to tetrapeptide salt 8 with an uncapped N-terminus. Hydrochloride of

Synthesis of (S)-1-(2-chloroacetyl)pyrrolidine- 2-carbonitrile: A key intermediate for dipeptidyl peptidase IV inhibitors

• Santosh K. Singh,
• Narendra Manne and
• Manojit Pal

Beilstein J. Org. Chem. 2008, 4, No. 20, doi:10.3762/bjoc.4.20

• molecules [1][2][3]. DPP-IV, a member of the prolyl oligopeptidase family of serine protease, cleaves the N-terminal dipeptide from peptides with proline or alanine in the second position. As a result of intense pharmaceutical research, several DPP-IV inhibitors have been discovered and a few of them

• control of glucose homeostasis in patients with type-II diabetes. However, in the presence of plasma DPP-IV the active form of GLP-1 is inactivated rapidly (t1/2~1 min) due to the cleavage of a dipeptide from the N-terminus [14][15]. Thus inhibition of DPP-IV extends the half-life of endogenously secreted

Single and double stereoselective fluorination of (E)-allylsilanes

• Marcin Sawicki,
• Angela Kwok,
• Matthew Tredwell and
• Véronique Gouverneur

Beilstein J. Org. Chem. 2007, 3, No. 34, doi:10.1186/1860-5397-3-34

• C-S bonds. [22][23][24][25][26][27] With the nitrogen-based electrophile NO2BF4, this methodology delivers acyclic (E)-olefin dipeptide isosteres featuring two allylic stereocentres.[28][29] Herein, we report our investigation into the fluorination of (E)-allylsilanes of general structure B. A