Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• cold 0.2 M glycine buffer at pH 10.5 was added. The amount of hydrolyzed 7-amino-4-methylcoumarin (AMC) was measured in a Tecan Infinite M200 PRO fluorescence spectrophotometer (excitation and emission at λ = 365 and 440 nm, respectively). Bestatin [12] and DMSO were used as positive and negative

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• diastereoselective Michael addition reactions [103][104]. The glycine–nickel complex 184 was deprotonated using a radical anion generated from the electrochemical reduction of azobenzene. The anionic Ni complex 185 acted as a good C-nucleophile towards Michael acceptors 186 resulting in diastereoisomeric mixtures of

In search of visible-light photoresponsive peptide nucleic acids (PNAs) for reversible control of DNA hybridization

• Lei Zhang,
• Greta Linden and
• Olalla Vázquez

Beilstein J. Org. Chem. 2019, 15, 2500–2508, doi:10.3762/bjoc.15.243

• -penetrating wavelengths. Peptide nucleic acids (PNAs) [31] are synthetic nucleic acid analogues, in which nucleobases are linked to a repeating N-(2-aminoethyl)glycine polyamide backbone. The lack of phosphate groups provides them with both higher binding affinities to complementary DNA or RNA sequences and

• )aminoethyl]glycine residue –Aeg(Alloc)– was selectively deprotected in the presence of Pd(OAc)2, Ph3P, NMM, PhSiH3 in CH2Cl2 for 2 h. Subsequently, carboxy photoswitches were introduced using Oxyma and N,N’-diisopropylcarbodiimide (DIC) as coupling agent. We explored two different types of photoswitches

• . Black lines controls: solid: FAM-ssDNA without PNA and under the same conditions; dashed: BHQ/FAM-dsDNA. Solid-phase synthesis of photoswitchable PNAs; Aeg = N-(2-aminoethyl)glycine, Bhoc = benzhydryloxycarbonyl. Isomerization conversions at the photostationary state (PSS). Melting temperatures (TM) of

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• diterpene synthases. Hence, the discovery of this novel motif might help in the identification and functional assignment of novel TPSs. The importance of the tryptophan residue in the WXXXXXRY motif of CotB2 was proven by mutation to glycine (W288G), where the product was changed to 3,7,18-dolabellatriene

Design, synthesis and biological evaluation of immunostimulating mannosylated desmuramyl peptides

• Rosana Ribić,
• Ranko Stojković,
• Lidija Milković,
• Mariastefania Antica,
• Marko Cigler and
• Srđanka Tomić

Beilstein J. Org. Chem. 2019, 15, 1805–1814, doi:10.3762/bjoc.15.174

• synthesized and biologically evaluated [19][20][21]. The best adjuvant activity in experiments in vivo showed the ManAdTP derivative (Figure 2) which has a ᴅ-configuration at the (adamant-1-yl)glycine moiety and (R)-configuration at the hydroxyisobutyryl linker. Its activity was higher than PGM that was used

• racemic Boc-protected (adamant-1-yl)glycine [32] 2 using the carbodiimide EDC/HOBt method [21]. The obtained mixture of BocAdGly-ʟ-Ala-ᴅ-isoGlnOBn diastereoisomers was treated with trifluoroacetic acid in order to remove the Boc protecting group while the diastereoisomer 4 with ᴅ-ʟ-ᴅ amino acid sequence

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

A chemically contiguous hapten approach for a heroin–fentanyl vaccine

• Yoshihiro Natori,
• Candy S. Hwang,
• Lucy Lin,
• Lauren C. Smith,
• Bin Zhou and
• Kim D. Janda

Beilstein J. Org. Chem. 2019, 15, 1020–1031, doi:10.3762/bjoc.15.100

• , norheroin (1, Figure 3). Thus, norheroin (1) was synthesized according to literature procedure and purified by recrystallization [16]. Alkylation of 1 with tert-butyl bromoacetate and subsequent deprotection with trifluoroacetic acid yielded the N-glycine derivative of norheroin, 16. This critical

• corresponding alkene resulted in a mixture of products. We opted to try the synthesis of HF-2 by 1,4-addition, rather than reductive amination. Thus, intermediate 5 was acylated with acryloyl chloride to give the α,β-unsaturated intermediate 10 (Scheme 1). Condensation with a tert-butyl-protected glycine

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• and Constabel [17] who developed a solid phase strategy to obtain tetrazoles and hydantoinimide derivatives successfully (Scheme 2). In each case, the synthetic sequence began with a classical Ugi reaction between N-Fmoc glycine (1), isobutyraldehyde (2) and tert-butyl isocyanide (4) in the presence

• reactions in the synthesis of macrocycles (which were considered as macroheterocycles in the context of this review). In this respect, Wessjohann et al. developed a methodology for the synthesis of cyclic RGD pentapeptoids (RGD = arginine-glycine-aspartic acid) by consecutive Ugi reactions [32]. This was

Azologization of serotonin 5-HT₃ receptor antagonists

• Karin Rustler,
• Galyna Maleeva,
• Piotr Bregestovski and
• Burkhard König

Beilstein J. Org. Chem. 2019, 15, 780–788, doi:10.3762/bjoc.15.74

• nicotinic acetylcholine receptors (nAChRs), γ-aminobutyric acid type A receptors (GABAARs), and glycine receptors (GlyRs). To date, five subunits of the 5-HT3 receptor are identified (5-HT3A–5-HT3E) [21]. Functional receptors are either constructed as 5-HT3A homopentamers or as heteropentamers containing 5

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

• Guillaume Ernouf,
• Jean-Louis Brayer,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

• at 40 °C but could be accelerated by addition of Ti(OiPr)4 (10 mol %) to deliver the corresponding N-Boc- carbamate 36 (81%). The condensation of isocyanate 28 with N-Boc-glycine in the presence of DMAP (Goldschmidt–Wick coupling) [57] provided amide 37 in 70% yield (Scheme 16) [53]. The examination

Cross metathesis-mediated synthesis of hydroxamic acid derivatives

• Shital Kumar Chattopadhyay,
• Subhankar Ghosh and
• Suman Sil

Beilstein J. Org. Chem. 2018, 14, 3070–3075, doi:10.3762/bjoc.14.285

• synthesis of the unusual amino acid component of the important anticancer cyclic peptide compound Chap-31, we attempted the cross-metathesis reaction of N-benzyloxyacryl amide 5 with the homoallylglycine derivative 4k (Table 1, entry 11) and the bis-homoallyl glycine derivative 4l (Table 1, entry 12) [32

N-Acylated amino acid methyl esters from marine Roseobacter group bacteria

• Hilke Bruns,
• Lisa Ziesche,
• Nargis Khakin Taniwal,
• Laura Wolter,
• Thorsten Brinkhoff,
• Jennifer Herrmann,
• Rolf Müller and
• Stefan Schulz

Beilstein J. Org. Chem. 2018, 14, 2964–2973, doi:10.3762/bjoc.14.276

• compounds proved to be either new NAMEs or constitute new classes of acylated amino acid methyl esters, derived from valine (NAVME), glycine (NAGME), or 2-aminobutyric acid (NABME). The identification of these compounds will be discussed based on the outlined approach including GC/MS analysis

• ). The spectra show characteristic ions at m/z 90, 131, and 144 (Figure 6), a loss of one methylene group compared to ions m/z 104, 145, and 158 of NAMEs. The lack of an analogous ion to m/z 44 (m/z 30 is outside the mass range of the spectrometer used) pointed this time to glycine as the core amino acid

• compound R to be N-[(Z)-hexadec-9-enoyl]glycine methyl ester (11, Z9-C16:1-NAGME), while S is its saturated analogue. Therefore, both compounds were synthesized as described before from glycine methyl ester and the respective acid (Scheme 2) and their identity confirmed. The other components P, Q and T–W

Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions

• Glwadys Gagnot,
• Vincent Hervin,
• Eloi P. Coutant,
• Sarah Desmons,
• Racha Baatallah,
• Victor Monnot and
• Yves L. Janin

Beilstein J. Org. Chem. 2018, 14, 2846–2852, doi:10.3762/bjoc.14.263

• de la Recherche Scientifique, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France Université Paris Descartes, Sorbonne Paris Cité, 12 rue de l'École de Médecine, 75006 Paris, France 10.3762/bjoc.14.263 Abstract We report here on the use of ethyl nitroacetate as a glycine template to produce α-amino

• esters was required to prepare a corresponding array of analogues. As we reviewed recently, nitroacetates are amongst the principal glycine templates used to prepare α-amino esters 1 [2]. The retrosynthetic pathway depicted in Scheme 1 requires a reduction of ethyl nitroacrylates 2, which are made from

• function of 16, followed by its coupling with glycine or phenylalanine ethyl esters (respectively 20a and 20b) using 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate (TBTU) as a coupling agent to give the corresponding amides 21a,b. The isoxazole ring of these compounds was then

Non-native autoinducer analogs capable of modulating the SdiA quorum sensing receptor in Salmonella enterica serovar Typhimurium

• Matthew J. Styles and
• Helen E. Blackwell

Beilstein J. Org. Chem. 2018, 14, 2651–2664, doi:10.3762/bjoc.14.243

• SdiA by greater than 30%. These compounds could be classified as follows: long chain AHLs (12–16 carbons); BHLs, PHLs and PPHLs with large substituents on the aryl ring; glycine ethyl ester replacements for the lactone head group; and compound 11 (ITC-12), originally reported by the Meijler lab [44

• , C18, E6, E33, E34, and F13), and PHL-type derivatives with glycine ethyl ester head groups (F39, F40, F45, and F47). In addition, an AHL with an electrophilic warhead for covalent modification (11, ITC-12) and various non-AHL compounds (12, 13, 18, 19R, and 20) were found to be SdiA antagonists. Most

• activity in the SdiA reporter assay, and recently reported data for LasR suggestive of a closed ligand-binding site for maximal activation [65]. All of the glycine ethyl ester head group compounds tested exhibited SdiA antagonism despite varying between a range of PHL- and PPHL-type tails with differing

Synthesis of a leopolic acid-inspired tetramic acid with antimicrobial activity against multidrug-resistant bacteria

• Luce Mattio,
• Loana Musso,
• Leonardo Scaglioni,
• Andrea Pinto,
• Piera Anna Martino and
• Sabrina Dallavalle

Beilstein J. Org. Chem. 2018, 14, 2482–2487, doi:10.3762/bjoc.14.224

• ester nitrogen we chose the p-methoxybenzyl (PMB) group, easily removable by ceric ammonium nitrate (CAN). N-(4-Methoxybenzyl)glycine ethyl ester (5) was obtained in 87% yield by reacting 4-methoxybenzylamine (3) with bromoacetic acid ethyl ester (4) in THF (Scheme 1). The ester 5 was converted into

Applications of organocatalysed visible-light photoredox reactions for medicinal chemistry

• Michael K. Bogdos,
• Emmanuel Pinard and
• John A. Murphy

Beilstein J. Org. Chem. 2018, 14, 2035–2064, doi:10.3762/bjoc.14.179

• . Naturally occurring amino acids, e.g., glycine, are often used in medicinal chemistry as linkers, structural components of scaffolds or even as precursors to useful building blocks. Wallentin and co-workers have described a method for the reductive decarboxylation of amino acids, using bis(4-chlorophenyl

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

• Deepankar Das,
• Rudrajit Mal,
• Nisha Mittal,
• Zhengbo Zhu,
• Thomas J. Emge and
• Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

• possesses a shortened amide bridge to allow for the formation of bimetallic complexes with all five-membered chelate rings. Ligand 22-H2 was obtained starting from glycinol 17 and N-carboxybenzyl glycine (20) via the sequence of steps outlined in Scheme 2. While X-ray quality crystals have not yet been

Diazirine-functionalized mannosides for photoaffinity labeling: trouble with FimH

• Femke Beiroth,
• Tomas Koudelka,
• Thorsten Overath,
• Stefan D. Knight,
• Andreas Tholey and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1890–1900, doi:10.3762/bjoc.14.163

• from p-nitrophenyl α-D-mannopyranoside (1), which was first reduced to the corresponding amine 6 [26][27] by catalytic hydrogenation (Scheme 1). HATU-mediated peptide coupling with Boc-protected glycine under basic conditions led to 7. After removal of the Boc protecting group using trifluoroacetic

• , Caryl-1), 133.3 (1C, Caryl-4‘), 129.3 (2C, CHaryl-2‘,6‘), 127.7 (2C, CHaryl-3‘,5‘), 122.9 (2C, CHaryl-2,6), 121.3 (1C, q, J = 274.9 Hz, CF3), 118.2 (2C, CHaryl-3,5), 100.6 (1C, C-1), 75.4 (1C, C-5), 72.4 (1C, C-3), 72.0 (1C, C-2), 68.4 (1C, C-4), 62.7 (1C, C-6), 44.4 (1C, CH2-glycine) ppm; 19F NMR (471

• -mannopyranosyloxy)]phenyl amide (7). The aminophenyl mannoside 6 [26][27] (150 mg, 553 µmol) was dried together with N-Boc-glycine (64.6 mg, 369 µmol) and HATU (280 mg, 738 µmol) for 45 min under vacuum. Afterwards, this mixture was dissolved in dry DMF (8 mL), DIPEA (80.0 µL, 443 µmol) was added and the reaction

Synthesis and photophysical studies of a multivalent photoreactive Ru^II-calix[4]arene complex bearing RGD-containing cyclopentapeptides

• Sofia Kajouj,
• Lionel Marcelis,
• Alice Mattiuzzi,
• Adrien Grassin,
• Damien Dufour,
• Pierre Van Antwerpen,
• Didier Boturyn,
• Eric Defrancq,
• Mathieu Surin,
• Julien De Winter,
• Pascal Gerbaux,
• Ivan Jabin and
• Cécile Moucheron

Beilstein J. Org. Chem. 2018, 14, 1758–1768, doi:10.3762/bjoc.14.150

• in the IR spectrum of 4. Phenanthroline derivative 5 was synthesized from 5-glycinamido-1,10-phenanthroline in a two-step sequence consisting of a peptide-type coupling reaction with a Boc-protected glycine N-hydrosuccinimide ester followed by the deprotection of the amino group (see Supporting

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• our group. These were applied to the asymmetric alkylation reaction of benzophenone imine of glycine ester which has become one of the benchmark reactions for examining the performance of new phase-transfer catalysts [36]. Later in 2010, Shirakawa and Shimizu reported the synthesis of novel inherently

• chiral calix[4]arene derivatives 9–15 (Figure 2) bearing secondary amides at lower rim have been designed as catalysts and employed in the asymmetric alkylation of N-(diphenylmethylene)glycine esters. Among them, α-methylbenzylamine-derived calixarene-methoxy-triamide 12 afforded the (R)-benzylated

• . Synthesis of chiral calix[4]arene-based phase-transfer catalyst 7 and structure of O’Donnell’s N-benzylcinchonine 8. Asymmetric alkylation of glycine derivative 3 catalyzed by calixarene-based phase-transfer catalyst 7. Phase-transfer alkylation of 3 catalyzed by calixarene-triamide 12. Synthesis of

On the design principles of peptide–drug conjugates for targeted drug delivery to the malignant tumor site

• Eirinaios I. Vrettos,
• Gábor Mező and
• Andreas G. Tzakos

Beilstein J. Org. Chem. 2018, 14, 930–954, doi:10.3762/bjoc.14.80

• -glycine-aspartic acid (RGD): A widely applied peptide carrier is the tripeptide arginine-glycine-aspartic acid (RGD) motif, which was first identified by Ruoslahti and Pierschbacher in the early 1980s [40] within fibronectin that mediates cell attachment and was known to target integrin α5β1 [41]. In

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• such intermediates. By selecting the appropriate reaction conditions (various pH and temperatures), they were able to alkylate free amino acids, e.g., glycine (Gly), L-serine (Ser), L-cysteine (Cys), L-lysine (Lys), L-tyrosine (Tyr) and glutathione (Glu) in aqueous solution to isolate 55 (Scheme 8

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu₄NI

• Mi-Hai Luo,
• Yang-Ye Jiang,
• Kun Xu,
• Yong-Guo Liu,
• Bao-Guo Sun and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

• amino acids has always been paid much attention in industrial and academic setting and many advances have been made [12][13][14][15][16][17]. Li et al. first reported the functionalization of glycine derivatives with malonates using a stoichiometric quantity of Cu(OAc)2 as catalyst and oxidant [12

• ]. Later on, arylation, vinylation and alkynylation of glycine derivatives were also accomplished by the same group (Scheme 1) [13]. Using the Cu(OAc)2/pyrrolidine dual catalysts system, Huang developed the oxidative cross coupling of glycine derivatives with acetone in the presence of TBHP or DDQ as

• terminal oxidants [14]. The protocol was also extended to reactions with 2-alkylquinoline [15] and phenols [16] using O2 and di-tert-butyl peroxide (DTBP) as oxidant, respectively (Scheme 1). A CuCl-catalyzed oxidative cross coupling of glycine derivatives with indoles has been developed by Hou et al

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

• Fabio Tonin and
• Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

• are related to the position and stereochemistry of the hydroxy groups attached to the steroid ring. A general structure with the names of several bile acids is reported in Figure 2. Deconjugation Free bile acids can be obtained from the corresponding bile amides (with glycine and taurine) through a

• , EC: 3.5.1) have been reported to hydrolyse glycinates and taurinates to the corresponding carboxylic acid. Recently, Pedrini et al. [33] have isolated and characterized a cholylglycine hydrolase from Xanthomonas maltophilia CBS 827.97: this enzyme completely hydrolyses glycine and taurine conjugates

Synthesis and biological evaluation of RGD and isoDGR peptidomimetic-α-amanitin conjugates for tumor-targeting

• Lizeth Bodero,
• Paula López Rivas,
• Barbara Korsak,
• Torsten Hechler,
• Andreas Pahl,
• Christoph Müller,
• Daniela Arosio,
• Luca Pignataro,
• Cesare Gennari and
• Umberto Piarulli

Beilstein J. Org. Chem. 2018, 14, 407–415, doi:10.3762/bjoc.14.29

• ][10][11], and therefore constitutes a suitable therapeutic target in the field of SMDCs. Integrin αVβ3 recognizes endogenous ligands by the tripeptide arginine-glycine-aspartate [12] (RGD) and also by the related sequence isoaspartate-glycine-arginine (isoDGR) [13][14][15][16][17][18][19][20]. Many