Building photoswitchable 3,4'-AMPB peptides: Probing chemical ligation methods with reducible azobenzene thioesters

• Gehad Zeyat and
• Karola Rück-Braun

Beilstein J. Org. Chem. 2012, 8, 890–896, doi:10.3762/bjoc.8.101

• we had to place the ligation junction next to the third amino acid serine of the SKV binding motif. In the case of the conventional NCL, we used cysteine at the ligation site, and for the auxiliary mediated ligations, we decided to introduce auxiliary-glycine-conjugates at the N-terminus, due to the

• procedures (Supporting Information File 1) [4][17]. The syntheses of the auxiliary-linked glycine conjugates 7 and 8 were accomplished by using literature protocols developed by Dawson, Offer and MacMillan [7][8] (Figure 2). The Cys-peptide 3 and the Nα-auxiliary peptides 4 and 5 were assembled on Wang resin

• for the application in ligation studies. AMPB = (aminomethylphenylazo)benzoic acid. Structure of the glycine-linked auxiliary conjugates 7 and 8. Structural differences between the trans- and the cis-state of azopeptides with a SKV PDZ binding motif. Solid-phase synthesis of the ligation-mediating

High-affinity multivalent wheat germ agglutinin ligands by one-pot click reaction

• Henning S. G. Beckmann,
• Heiko M. Möller and
• Valentin Wittmann

Beilstein J. Org. Chem. 2012, 8, 819–826, doi:10.3762/bjoc.8.91

• ][29][30][31][32][33][34][35][36] or from screening of combinatorial libraries [37][38] have been reported. WGA is a 36 kDa plant lectin composed of two identical glycine- and cysteine-rich subunits [39] and is enriched in the seeds of Triticum vulgaris. It is specific for terminal N-acetylneuraminic

Synthetic glycopeptides and glycoproteins with applications in biological research

• Ulrika Westerlind

Beilstein J. Org. Chem. 2012, 8, 804–818, doi:10.3762/bjoc.8.90

• amine group is reduced resulting in longer coupling times and lower yields. Therefore, the auxiliary method is mainly applied when the ligation site contains a glycine residue. To avoid these limitations, a ligation methodology has been developed with the thiol group linked to the amino-acid side-chain

An easily accessible sulfated saccharide mimetic inhibits in vitro human tumor cell adhesion and angiogenesis of vascular endothelial cells

• Grazia Marano,
• Claas Gronewold,
• Martin Frank,
• Anette Merling,
• Christian Kliem,
• Sandra Sauer,
• Manfred Wiessler,
• Eva Frei and
• Reinhard Schwartz-Albiez

Beilstein J. Org. Chem. 2012, 8, 787–803, doi:10.3762/bjoc.8.89

• with the ECM. To characterize the affected interactions in more detail, cells were incubated with peptidic integrin ligands and GSF in combination. The RGD motif (an arginine–glycine–aspartic acid peptide sequence) is recognized and bound by several integrins including αvβ3 and α5β1. The sequence

• -containing peptide: glycine–arginine–glycine–aspartic acid–serine–proline (GRGDSP) or EILDV. Neither peptide, up to 2 mM, completely inhibited adhesion of WM-115 cells to fibronectin. We then decided to combine the peptidic integrin ligands with GSF to see if an antagonism or additive effect upon cell

Investigation of the network of preferred interactions in an artificial coiled-coil association using the peptide array technique

• Raheleh Rezaei Araghi,
• Carsten C. Mahrenholz,
• Rudolf Volkmer and
• Beate Koksch

Beilstein J. Org. Chem. 2012, 8, 640–649, doi:10.3762/bjoc.8.71

• positions relevant to coiled-coil binding were replaced with glycine. As depicted in Figure 3, both/either (i) hydrophobic (a15,d18) and/or electrostatic (e19,g21) positions of the central heptad or (ii) essential hydrophobic positions in the flanking heptads were substituted with glycine. This set of

• representatives). The second and third classes contain the mutants with SI values lower than those of the strong binders but still above 50% and 25% of that of Acid-pp, respectively. The poor binders have SI values below 25% of that of Acid-pp. This group also contains the aforementioned glycine-mutants. For each

• interact efficiently with B3β2γ. The glycine-scan (Figure 3) reveals the nature of the chimeric coiled-coil interaction. Only the acid-pp wt shows strong binding to B3β2γ. If the hydrophobic or electrostatic regions essential for coiled-coil binding are blocked by glycine, the signal breaks down. As

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

A concise synthesis of 3-(1-alkenyl)isoindolin-1-ones and 5-(1-alkenyl)pyrrol-2-ones by the intermolecular coupling reactions of N-acyliminium ions with unactivated olefins

• Nianhong Lu,
• Lihong Wang,
• Zhanshan Li and
• Wei Zhang

Beilstein J. Org. Chem. 2012, 8, 192–200, doi:10.3762/bjoc.8.21

• 1-alkenylboronic acid, or esters [23][24] besides allylsilane. For example, Angst reported the coupling of styrylsilanes with N-acyl-2-chloroglycine esters catalyzed by SnCl4 to give the 3-styryl glycine derivatives in 1987 [19]; Wistrand reported the coupling of methyl 1-acyl-5-methoxy-L-proline

Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

• Li-Si Huang,
• Fei He,
• Hui Huang,
• Xiao-Yong Zhang and
• Shu-Hua Qi

Beilstein J. Org. Chem. 2012, 8, 170–176, doi:10.3762/bjoc.8.18

• towards E. coli at 25 μg/disc. It was reported that taurine and its derivatives have a number of physiological functions, including interference with GABA and glycine receptors, antinociceptic effects, anticonvulsive actions, neuroprotective actions, etc. [14]. In this study, because of the limited

Synthesis of fused tricyclic amines unsubstituted at the ring-junction positions by a cascade condensation, cyclization, cycloaddition then decarbonylation strategy

• Iain Coldham,
• Adam J. M. Burrell,
• Hélène D. S. Guerrand,
• Luke Watson,
• Nathaniel G. Martin and
• Niall Oram

Beilstein J. Org. Chem. 2012, 8, 107–111, doi:10.3762/bjoc.8.11

• (R = Et) with glycine ethyl ester to give the tricyclic product 2 [19][20] (Scheme 1). In this chemistry, the intermediate imine undergoes cyclization onto the tethered alkyl chloride to give an iminium ion which deprotonates to give an azomethine ylide that undergoes dipolar cycloaddition with the

• alkene. A single stereoisomer of product 2 was formed. Alternatively, glycine could be used and led to a tricyclic product via an intermediate azomethine ylide formed by decarboxylation. Unfortunately, when the substrate 1 (R = H) was used, heating with glycine or glycine ethyl ester did not yield the

• -protection gave the alcohol 12 which was oxidized to aldehyde 8a. Cascade condensation, cyclization, cycloaddition The cascade tricyclic ring formation was then investigated with the aldehydes 6, 8a and 8b. Heating aldehyde 6 with glycine gave a mixture of unidentifiable products. However, heating with

Synthesis and characterization of new diiodocoumarin derivatives with promising antimicrobial activities

• Hany M. Mohamed,
• Ashraf H. F. Abd EL-Wahab,
• Ahmed M. EL-Agrody,
• Ahmed H. Bedair,
• Fathy A. Eid,
• Mostafa M. Khafagy and
• Kamal A. Abd-EL-Rehem

Beilstein J. Org. Chem. 2011, 7, 1688–1696, doi:10.3762/bjoc.7.199

• with p-phenylenediamine in boiling AcOH afforded the 6,8-diiodocoumarin-3-carboxamide derivatives 4 and 5, respectively. Interaction of 3 with glycine in dry benzene under reflux gave the new 6,8-diiodocoumarin-3-N,N-dimethylcarboxamide (7) instead of 6,8-diiodocoumarin-3-ylcarbonylglycine (6). The

• formation of compound 7 suggests that two glycine molecules react with 1 followed by the loss of ammonia and decarboxylation, furnishing the observed product (Scheme 1). The structures of compounds 3–5 and 7 were confirmed by IR, 1H NMR, 13C NMR and MS. The IR spectra for compound 3 showed 1774, 1718 cm−1

• (M – CH2=C=O, 38.7), 424 (18.2), 341 (33.8), 298 (6.5), 171 (9.3), 107 (100). 6,8-Diiodocoumarin-3-N,N-dimethylcarboxamide (7). A solution of compound 3 (0.46 g, 1 mmol) in dry benzene (50 mL) was refluxed with glycine (0.75 g, 10 mmol) for 2 h. After cooling, the solid formed was filtered off

Photochemical and thermal intramolecular 1,3-dipolar cycloaddition reactions of new o-stilbene-methylene-3-sydnones and their synthesis

• Kristina Butković,
• Željko Marinić,
• Krešimir Molčanov,
• Biserka Kojić-Prodić and
• Marija Šindler-Kulyk

Beilstein J. Org. Chem. 2011, 7, 1663–1670, doi:10.3762/bjoc.7.196

• Abstract New trans- and cis-o-stilbene-methylene-sydnones 3a,b were synthesized by transforming the trans- and cis-o-aminomethylstilbene derivative, obtained by reduction of corresponding o-cyano derivatives, into glycine ester derivatives (43 and 31% yield) followed by hydrolysis (90 and 96% yield

• carbonyl carbon at ~172 ppm in the 13C NMR spectra. The esters 8a or 8b were hydrolysed to the amino acid 9a (trans, 90%) or 9b (cis, 96%). The obtained amino acids were transformed to N-nitroso glycine 10a or 10b and, without isolation or further purification, were submitted to dehydration with acetic

Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes

• Jan-Christoph Kehr,
• Douglas Gatte Picchi and
• Elke Dittmann

Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191

• [28]. The precursor is formed via the activity of the unique L-arginine-glycine amidinotransferase CyrA (AoaA in A. ovalisporum) [29][30] (Figure 4C). The assembly line further comprises seven additional malonyl-CoA specific PKS modules [28]. It has been discussed that the three cyclization steps

A straightforward approach towards combined α-amino and α-hydroxy acids based on Passerini reactions

• Ameer F. Zahoor,
• Sarah Thies and
• Uli Kazmaier

Beilstein J. Org. Chem. 2011, 7, 1299–1303, doi:10.3762/bjoc.7.151

• aldehyde group. Therefore, we decided to run the reaction also under neat conditions as reported for the γ-oxo-amino acids. With acetic acid as the acidic component the yield of 6a was comparable to the previous examples. In principle, other acids such as benzoic acid or Cbz-protected glycine can be used

Metathesis access to monocyclic iminocyclitol-based therapeutic agents

• Ileana Dragutan,
• Valerian Dragutan,
• Carmen Mitan,
• Hermanus C.M. Vosloo,
• Lionel Delaude and
• Albert Demonceau

Beilstein J. Org. Chem. 2011, 7, 699–716, doi:10.3762/bjoc.7.81

• both during ester group reduction and the subsequent steps. By a similar approach (Scheme 4), these authors also obtained the enantiopure homoiminocyclitol (−)-(2S,3R,4S,5S)-2,5-dihydroxymethylpyrrolidin-3,4-diol (23). Starting from the same racemic vinyl glycine methyl ester and introducing enzymatic

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

• established which gave the desired product in 90% overall yield (Scheme 33). Alternatively, glycine can be reacted with methyl pentanimidate 169 to form the corresponding amidine 171 in high yield. Cyclisation, followed by a Vilsmeier-type reaction then furnishes the key chloroimidazolyl building block 172 in

A two step synthesis of a key unit B precursor of cryptophycins by asymmetric hydrogenation

• Benedikt Sammet,
• Mathilde Brax and
• Norbert Sewald

Beilstein J. Org. Chem. 2011, 7, 243–245, doi:10.3762/bjoc.7.32

• %). Unit B synthesis by a chiral PTC approach. Reagents and conditions [9]: a) N-(Diphenylmethylene)glycine tert-butyl ester, 50% KOH, toluene/CHCl3, chiral phase transfer catalyst (0.01 equiv), 0 °C, 20 h (87%; 96% ee); b) 15% citric acid, THF, rt, 16 h; c) FmocCl, Na2CO3, THF, rt, 14 h, (72% over two

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• the new 5-aminopyrazole acid ester 140. Reaction of 140 with the acid chloride of (9-fluoroenylmethyl)carbamate(Fmoc)-protected glycine led to peptide coupling and subsequent Fmoc deprotection with piperidine gave 141. A second coupling step can also be performed with Fmoc-protected glycine acid

Kinetic studies and predictions on the hydrolysis and aminolysis of esters of 2-S-phosphorylacetates

• Milena Trmčić and
• David R. W. Hodgson

Beilstein J. Org. Chem. 2010, 6, 732–741, doi:10.3762/bjoc.6.87

• aminolysis using glycine ethyl ester, with the pKaH of the amine being identical to that of D-glucosamine. Glycine ethyl ester displayed kNH2 = 1.1 M−1s−1 and 22.6 M−1s−1 when used in reactions with 2-nitrophenyl 2-(ethylthio)acetate and 2-nitrophenyl acetate, respectively. In our studies, using D

Synthesis of the fluorescent amino acid rac-(7-hydroxycoumarin-4-yl)ethylglycine

• Manfred Braun and
• Torsten Dittrich

Beilstein J. Org. Chem. 2010, 6, No. 69, doi:10.3762/bjoc.6.69

• proteins, has been synthesized in five steps from commercially available (7-hydroxycoumarin-4-yl)acetic acid. The key step involves the alkylation of a glycine–enolate equivalent. Keywords: alkylation; coumarin; fluorescent probe; glycine; protecting group; Introduction The incorporation of non-natural

• , alkylation of a glycine enolate with the primary bromide 5 was anticipated. Indeed, its use as the electrophilic component in the coupling with the benzophenone-derived imine of tert-butyl glycine 6, which functioned, after deprotonation, as a synthetic equivalent of a glycine enolate synthon, led to the

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

Fused bicyclic piperidines and dihydropyridines by dearomatising cyclisation of the enolates of nicotinyl-substituted esters and ketones

• Heloise Brice,
• Jonathan Clayden and
• Stuart D. Hamilton

Beilstein J. Org. Chem. 2010, 6, No. 22, doi:10.3762/bjoc.6.22

• scope of the dearomatisation can be extended to much less reactive nucleophiles with a more electron deficient aromatic acceptor [39][40][41]. Thus enolates of glycine esters 1 carrying isonicotinoyl or nicotinoyl N-substituents cyclise readily to yield bicyclic amino acid derivatives 2 (Scheme 1a for

(−)-Complanine, an inflammatory substance of marine fireworm: a synthetic study

• Kazuhiko Nakamura,
• Yu Tachikawa and
• Daisuke Uemura

Beilstein J. Org. Chem. 2009, 5, No. 12, doi:10.3762/bjoc.5.12

• configuration (of the OH adjacent carbon atom) is R [4]. The similarity of the structures suggests a close relationship in their biosynthetic pathways. It can be hypothesized that complanine is biosynthesized from glycine, based on comparison with serine- or alanine-derived natural products [3][4][10][11]. The

Synthesis of dihydrophenanthridines by a sequence of Ugi-4CR and palladium- catalyzed intramolecular C-H functionalization

• Florence Bonnaterre,
• Michèle Bois-Choussy and
• Jieping Zhu

Beilstein J. Org. Chem. 2008, 4, No. 10, doi:10.3762/bjoc.4.10

• ], the reaction of 3c with o-iodobenzaldehyde (2a), tert-butyl isocyanide (4a) and butyric acid (5a) or N-(tert-butoxycarbonyl)glycine (5c) afforded the corresponding Ugi adducts 6c and 6f in yields of 31% and 51%, respectively (entries 3, 6). The intramolecular C-H arylation process was found to be

Reactions of glycidyl derivatives with ambident nucleophiles; part 2: amino acid derivatives

• Gerald Dyker,
• Andreas Thöne and
• Gerald Henkel

Beilstein J. Org. Chem. 2007, 3, No. 28, doi:10.1186/1860-5397-3-28

• functionality, in both cases at a terminal carbon atom of 2. All attempts to achieve a one-step cyclization according to Scheme 1 starting from glycine or from phenylglycine seemed to fail under various reaction conditions (for instance one equiv. of NaOH, K2CO3 or triethylamine in water), regularly giving rise

• to solid, presumably oligomeric material, insoluble even in DMSO. We therefore tested the stepwise, controlled synthesis of products of type 3a with glycidyl esters of N-acyl [6] and N-tosyl glycine and phenylglycine as isolated key intermediates: under basic reaction conditions (NaH, sec-BuLi or LDA