Isolation and X-ray characterization of palladium–N complexes in the guanylation of aromatic amines. Mechanistic implications

• Abdessamad Grirrane,
• Hermenegildo Garcia and
• Eleuterio Álvarez

Beilstein J. Org. Chem. 2013, 9, 1455–1462, doi:10.3762/bjoc.9.165

• guanidines are commercially used as antifouling agents in marine paints and in the formulation of protective surface coatings [8][9][10]. N-Arylguanidines can be obtained by aniline insertion into the corresponding carbodiimide [11][12][13][14][15][16][17][18]. This nucleophilic addition can be efficiently

• the mechanism of aniline guanylation. When a stoichiometric (2:2:1) mixture of anilines 1a–c and carbodiimide 2 with PdCl2(MeCN)2 is stirred at 60 °C in CH2Cl2, evolution at initial reaction times of a solid precipitate is observed (Scheme 2). Filtration of these precipitates and subsequent washing

• (II) (3a–c) to the N,N’-diisopropylcarbodiimide (2) (Scheme 4). In this process, coordination of nitrogen to palladium should strongly reduce the nucleophilicity of the corresponding nitrogen atom and, therefore, the attack at the carbodiimide would be significantly slowed down compared to free

4-Pyridylnitrene and 2-pyrazinylcarbene

• Curt Wentrup,
• Ales Reisinger and
• David Kvaskoff

Beilstein J. Org. Chem. 2013, 9, 754–760, doi:10.3762/bjoc.9.85

• 2-pyridylnitrene (11). This leads to minor amounts of ketenimines 14 or glutacononitriles 15 beside the main product, the cyclic carbodiimide 12, which is formed in a degenerate rearrangement (11≡11). The major end products of FVT are the cyanopyrroles 16 and 17 (Scheme 2) [3][9][10][11]. Results

Thioester derivatives of the natural product psammaplin A as potent histone deacetylase inhibitors

• Matthias G. J. Baud,
• Thomas Leiser,
• Vanessa Petrucci,
• Mekala Gunaratnam,
• Stephen Neidle,
• Franz-Josef Meyer-Almes and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2013, 9, 81–88, doi:10.3762/bjoc.9.11

• avoid side reactions during the carbodiimide-mediated coupling step, whereby we had previously found the phenol to act as a competitive nucleophile. Since we had previously demonstrated the importance of the oxime (Scheme 1) for HDAC potency and selectivity, we prepared probes with these different

The multicomponent approach to N-methyl peptides: total synthesis of antibacterial (–)-viridic acid and analogues

• Ricardo A. W. Neves Filho,
• Sebastian Stark,
• Bernhard Westermann and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2012, 8, 2085–2090, doi:10.3762/bjoc.8.234

• coupling with carbodiimides, HBTU, HATU, and PyBroP failed or resulted in very low conversions. The addition of a catalytic amount of DMAP to the carbodiimide-mediated reactions improved the conversions, but resulted in severe racemization. The best result was obtained by employing N-ethoxycarbonyl-2

• -ethoxy-1,2-dihydroquinoline (EEDQ) as coupling reagent, which gave the optically active tripeptide 7 in 51% yield [16][17]. Intermediate 7 was converted into amine 8 under acidic conditions, and coupled directly to N,N-dimethylanthranilic acid (9). It was already reported that carbodiimide-mediated

Total synthesis and biological evaluation of fluorinated cryptophycins

• Christine Weiß,
• Tobias Bogner,
• Benedikt Sammet and
• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 2060–2066, doi:10.3762/bjoc.8.231

• -pentafluorophenylalanine was obtained by carbodiimide esterification of commercially available Boc-D-pentafluorophenylalanine (24) with trichloroethanol, followed by cleavage of Boc and reaction with acryloylchloride in the presence of base [19] (Scheme 3). The cryptophycin analogue with D-pentafluorophenylalanine as unit

Synthesis of szentiamide, a depsipeptide from entomopathogenic Xenorhabdus szentirmaii with activity against Plasmodium falciparum

• Friederike I. Nollmann,
• Andrea Dowling,
• Marcel Kaiser,
• Klaus Deckmann,
• Sabine Grösch,
• Richard ffrench-Constant and
• Helge B. Bode

Beilstein J. Org. Chem. 2012, 8, 528–533, doi:10.3762/bjoc.8.60

• -methylmorpholine (NMM) at 4 °C, affording the synthetic intermediate 4. The attempts to form the ester bond by using catalytic amounts of 4-dimethylaminopyridine (DMAP) with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), DMAP together with N,N′-diisopropylcarbodiimide (DIC), or a mixture of the DMAP

Azobenzene dye-coupled quadruply hydrogen-bonding modules as colorimetric indicators for supramolecular interactions

• Yagang Zhang and
• Steven C. Zimmerman

Beilstein J. Org. Chem. 2012, 8, 486–495, doi:10.3762/bjoc.8.55

• (DeUG) is described. The coupling of azobenzene dye 2 to mono-amido DAN units 4, 7, and 9 was effected by classic 4-(dimethylamino)pyridine (DMAP)-catalyzed peptide synthesis with N-(3-dimethylaminopropyl)-N’-ethyl carbodiimide hydrochloride (EDC) as activating agent, affording the respective amide

Synthesis of multivalent host and guest molecules for the construction of multithreaded diamide pseudorotaxanes

• Nora L. Löw,
• Egor V. Dzyuba,
• Boris Brusilowskij,
• Lena Kaufmann,
• Elisa Franzmann,
• Wolfgang Maison,
• Emily Brandt,
• Daniel Aicher,
• Arno Wiehe and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2012, 8, 234–245, doi:10.3762/bjoc.8.24

• Sonogashira coupling to the appropriate spacers: (a) EDC, HOBt, DMF, 22 h, 92%; (b) H2, Pd/C, EtOH, 3 d, 98%; (c) EDC.HCl, HOBt, DMF, 24 h, 73%; (d) I2, PIDA, AcOH/Ac2O, 1 h, 67%; (EDC = 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, HOBt = 1-hydroxybenzotriazole, DMF = N,N'-dimethylformamide, PIDA

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• (after removal of excess acrylic acid) with the aid of an oligomeric alkyl carbodiimide 44 (Scheme 19) [19]. Interestingly, Willis and coworkers have shown that aryl N-aminosulfonamides may be accessed by three-component coupling of aryl iodides, hydrazines, and DABCO·(SO2)2 as a convenient source of

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

• methylene chloride followed by condensation with β-ketonitriles 1 (Scheme 11) [42]. 1-ethyl-3-[3-(dimethylamino)propyl] carbodiimide hydrochloride (EDCI) mediated intramolecular cyclodehydration resulted in the formation of the 5,5-ring system, imidazo[1,2-b]pyrazol-2-one 46. 3-Oxopropanenitriles 16 on

(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• pseudooligosaccharides having cyanamide, urea and thiourea-linkages via the Staudinger reaction have been reported [69][70]. In our group, the carbodiimide approach was used to prepare calystegine B2 analogues with the urea-linked disaccharide structure (Figure 15). These compounds, however, did not show inhibitory

• negatively charged functional groups such as phosphate or carboxylate groups in DNA, RNA and proteins. Tóth and co-workers [90] synthesised a series of guanidine-linked sugars as a new class of oligosaccharide mimics to study their interactions with proteins. Thus, reaction of the carbodiimide-linked

• and on solvating properties. The guanidine derivatives showed higher Kas values than the isosteric thiourea and urea analogues. Ortiz Mellet’s group has reported the synthesis of N-benzylguanidine-linked dimeric cyclotrehalans (CT2s, 50) [78] via carbodiimide 49 by reaction with benzylamine

A facile synthesis and fungicidal activities of 2-(alkylamino)-5,6-dimethylthieno[2,3-d]pyrimidin- 4(3H)-ones

• Yang-Gen Hu,
• Ai-Hua Zheng,
• Xu-Zhi Ruan and
• Ming-Wu Ding

Beilstein J. Org. Chem. 2008, 4, No. 49, doi:10.3762/bjoc.4.49

• carbodiimide 4, which was used directly without further purification. To a solution of 4 (prepared above) in DCM (15 ml) was added the secondary amine (2 mmol). After the reaction mixture was stirred for 2–4 h, the solvent was removed and anhydrous ethanol (10 ml) with several drops of EtONa in EtOH were added

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

• stimulating the skin tanning process. In this paper we report the first solution phase synthesis of the title compound. The hexapeptide sequence has been assembled by [(2+2)+1+1] scheme. After removing the orthogonal protection, a carbodiimide mediated lactamization, involving the ε-amino group of lysine and

Inversion symmetry and local vs. dispersive interactions in the nucleation of hydrogen bonded cyclic n-mer and tape of imidazolecarboxamidines

• Sihui Long,
• Venkatraj Muthusamy,
• Peter G. Willis,
• Sean Parkin and
• Arthur Cammers

Beilstein J. Org. Chem. 2008, 4, No. 23, doi:10.3762/bjoc.4.23

• more complex molecule than the carboxamidine was isolated due to the inclusion of two carbodiimide moieties in the product; see Supporting Information File 1. Two other crystalline phases, with R1 = NH2, favored hydrogen bond tapes with the involvement of R1 hydrogen bonding. We spent little time on