Preparation of conjugated dienoates with Bestmann ylide: Towards the synthesis of zampanolide and dactylolide using a facile linchpin approach

• Jingjing Wang,
• Samuel Z. Y. Ting and
• Joanne E. Harvey

Beilstein J. Org. Chem. 2015, 11, 1815–1822, doi:10.3762/bjoc.11.197

• uncharted. In this paper, a three-component reaction between α,β-unsaturated aldehydes, alcohols and the Bestmann ylide is described. The scope of this esterification–Wittig reaction sequence in the synthesis of α,β,γ,δ-unsaturated esters is studied, and the method is applied in an approach towards the

• . Although fragment syntheses vary, the late-stage fragment assembly of the dactylolide macrocycle has centred mostly around construction of the C1–C5 dienoate by Wittig-type olefination reactions followed by ester hydrolysis and esterification with the C19 hydroxy group, combined with metathesis to form the

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• ) has been performed by Lotter and Bracher [67]. The route included four steps, but unfortunately, the overall yield was only 7%. Like in method A, the synthesis started with 1,10-phenanthroline to prepare binicotinic acid via oxidative cleavage by potassium permanganate. The esterification took place

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• in the esterification of the antineoplastic antibiotics mithramycin (5) catalyzed by Candida antarctica lipase A (CAL-A) and chromomycin A3 (6) catalyzed by Candida antarctica lipase B (CAL-B) [24]. In another report a series of mono-substituted troxerutin esters (7a) were synthesized by action of

• parent compound 12. A similar approach was followed later on by Lin and coworkers, who described the enzymatic esterification of the nucleoside 5-fluorouridine (13) and of other polyhydroxylated bioactive molecules with divinyl esters of dicarboxylic acids [31][32][33][34][35]. The monovinyl esters

• once again the well-known efficiency, selectivity and versatility of CAL-B (Novozyme 435) [16]. As in the previous examples, the mixed esters from the first esterification step can be used as acylating agents in the second esterification step. Scheme 3 shows the synthesis of the hybrid compounds 17 and

Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

• Karolina Żukowska,
• Eva Pump,
• Aleksandra E. Pazio,
• Krzysztof Woźniak,
• Luigi Cavallo and
• Christian Slugovc

Beilstein J. Org. Chem. 2015, 11, 1458–1468, doi:10.3762/bjoc.11.158

• Suzuki coupling as shown in Scheme 2 [14]. The cyano-substituted compound 10 was obtained without difficulty, but esterification of compound 9 was problematic because of purification issues (cf. Supporting Information File 1) so an alternative pathway was established. Starting from 2-bromoaniline upon

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Novel carbocationic rearrangements of 1-styrylpropargyl alcohols

• Christine Basmadjian,
• Fan Zhang and
• Laurent Désaubry

Beilstein J. Org. Chem. 2015, 11, 1017–1022, doi:10.3762/bjoc.11.114

• type of reaction has not been described before. It provides a useful alternative to the Rautenstrauch rearrangement, the main limitation of which lies on the necessity to have the alcohol esterified (Scheme 2) [8]. Indeed, in many cases, this esterification occurs in low yield, or may even be

Radical-mediated dehydrative preparation of cyclic imides using (NH₄)₂S₂O₈–DMSO: application to the synthesis of vernakalant

• Dnyaneshwar N. Garad,
• Subhash D. Tanpure and
• Santosh B. Mhaske

Beilstein J. Org. Chem. 2015, 11, 1008–1016, doi:10.3762/bjoc.11.113

• , hydrothermal cyclization, H2SO4 in acetic acid, PEG-600, silica supported TaCl5, esterification using inorganic base and alkylating agent followed by heating in the presence of tetrabutylammonium bromide, diphenyl 2-oxo-3-oxazolinylphosphonate and Et3N as well as several other conditions have been reported in

An intramolecular C–N cross-coupling of β-enaminones: a simple and efficient way to precursors of some alkaloids of Galipea officinalis

• Hana Doušová,
• Radim Horák,
• Zdeňka Růžičková and
• Petr Šimůnek

Beilstein J. Org. Chem. 2015, 11, 884–892, doi:10.3762/bjoc.11.99

• byproducts. A better and less time-consuming route to 10 consists of the reaction of 2-halobenzaldehyde 7 with Meldrum´s acid in the presence of HCOOH/Et3N system with a total yield of 61–67% (step f in Scheme 4). The last step for both methods was the esterification of acids 10a,b (step e in Scheme 4). β

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• procedures for acidic O-acylation of amino alcohols, Luh and Chong reported a method for selective aromatic esterification of amino alcohols in 1978, consisting of acylations of an amino

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• . KUNZE, Theaceae). It is the esterification product of epigallocatechin and gallic acid. Many studies provide evidence that EGCG modulates multiple signal transduction pathways, controlling the unwanted proliferation of cells. It inhibits the activation of HIF-1α, NF-κB and VEGF expression, thereby

Novel biphenyl-substituted 1,2,4-oxadiazole ferroelectric liquid crystals: synthesis and characterization

• Mahabaleshwara Subrao,
• Dakshina Murthy Potukuchi,
• Girish Sharada Ramachandra,
• Poornima Bhagavath,
• Sangeetha G. Bhat and
• Srinivasulu Maddasani

Beilstein J. Org. Chem. 2015, 11, 233–241, doi:10.3762/bjoc.11.26

• product 8 gives the carboxylic acid 9 which on esterification with different long chain alcohols gives various esters 10p–10s. The esters containing the benzyl ether group are deprotected to give the corresponding alcohols (11p–11s). Then they are treated with 4-bromobenzoic acid to give products 12p–12s

Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers

• Thorbjørn Terndrup Nielsen,
• Catherine Amiel,
• Laurent Duroux,
• Kim Lambertsen Larsen,
• Lars Wagner Städe,
• Reinhard Wimmer and
• Véronique Wintgens

Beilstein J. Org. Chem. 2015, 11, 147–154, doi:10.3762/bjoc.11.14

• the 100 nm range of potential biomedical interest. Results and Discussion CPT-dextrans Synthesis The synthesis of CPT-dextrans was achieved in two steps. First azide-modified CPT (N3CPT) was synthesized by esterification with 6-azidohexanoic acid mediated by EDC/DMAP (Scheme 1). TLC showed complete

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• compounds to form C–C, C–N, C–O, C–Hal, C–P, and N–N bonds [10], the Bu4NI/t-BuOOH oxidative system [22], selective functionalization of molecules [23], the oxidative esterification and oxidative amidation of aldehydes [24], and the transition metal-catalyzed radical oxidative cross-couplings [13]. The

• coupling. These processes with aldehydes or primary alcohols as C-reagents giving esters are often referred to as oxidative esterification. 2.1 Transition metal salt-catalyzed reactions using compounds with C=C, C=O, and C–Hal bonds as oxidants One of the types of the oxidative esterification is based on

• are used as the solvents or are taken in a large excess relative to the CH-reagent. 2.3 Reactions catalyzed by N-heterocyclic carbenes N-heterocyclic nucleophilic carbenes 105 have found use for the oxidative esterification. Scheme 23 shows, in a simplified way, the proposed mechanism of this type of

Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives

• Lisa Markenstein,
• Antje Appelt-Menzel,
• Marco Metzger and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 3087–3096, doi:10.3762/bjoc.10.325

• known to have a much lower toxic potential compared to CD monomers [20]. Native β-CD was already conjugated by esterification [21], reductive amination [22][23][24][25], amide coupling [26][27] and [2 + 3] cycloadditions [28] to both biogenic and synthetic polymers. Conjugation of CDs to polysaccharides

(2R,1'S,2'R)- and (2S,1'S,2'R)-3-[2-Mono(di,tri)fluoromethylcyclopropyl]alanines and their incorporation into hormaomycin analogues

• Armin de Meijere,
• Sergei I. Kozhushkov,
• Dmitrii S. Yufit,
• Christian Grosse,
• Marcel Kaiser and
• Vitaly A. Raev

Beilstein J. Org. Chem. 2014, 10, 2844–2857, doi:10.3762/bjoc.10.302

• secondary (4-Pe)Pro moiety and the hydroxy group of allo-Thr. Among several methods described in the literature for the creation of such bonds, the dialkylaminopyridine-promoted carbodiimide-mediated esterification was successfully employed here [62]. As far as the biological activities against L. donovani

Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction

• Vicky Gheerardijn,
• Jos Van den Begin and
• Annemieke Madder

Beilstein J. Org. Chem. 2014, 10, 2566–2572, doi:10.3762/bjoc.10.268

• of the pyrimidine double bond, transfer hydrogenation with cyclohexene as hydrogen source and 10% palladium on carbon should be used [60][61][62]. As the methyl ester derivative of the amino acid is commercially available but rather expensive, we performed the esterification reaction on the benzyl

Loose-fit polypseudorotaxanes constructed from γ-CDs and PHEMA-PPG-PEG-PPG-PHEMA

• Tao Kong,
• Lin Ye,
• Ai-ying Zhang and
• Zeng-guo Feng

Beilstein J. Org. Chem. 2014, 10, 2461–2469, doi:10.3762/bjoc.10.257

• anhydrous ether at 10 °C. The sequence was repeated three times. 1H NMR analysis indicated that the degree of esterification was >99%, and the yield was 83.4% (Figure S3, Supporting Information File 1). Synthesis of PHEMA-PPO-PEO-PPO-PHEMA via ATRP A typical procedure for the synthesis of the PHEMA-PPO-PEO

Syntheses of ¹⁵N-labeled pre-queuosine nucleobase derivatives

• Jasmin Levic and
• Ronald Micura

Beilstein J. Org. Chem. 2014, 10, 1914–1918, doi:10.3762/bjoc.10.199

• was accessible by first synthesizing ethyl [15N]-2-cyanoacetate (11) from 2-bromoacetic acid (9) and potassium cyanide [15N]-KCN, followed by esterification (Scheme 3). All further steps were conducted in direct analogy as described for target 1, namely reaction with guanidine hydrochloride to furnish

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

• in 28–64% ee [5]. In a similar fashion, Denmark’s oxazaphosphorinane cis-44a yielded keto esters 46a–c in high optical purities via conjugate addition to enones 41 followed by ozonolysis and oxidative esterification. Using diastereomer trans-44b on the other hand provided ketoesters 46a–c with only

• provided intermediate 165. Removal of the chiral auxiliary and generation of the second carboxy moiety was then achieved by ozonolysis of 165 and ensuing esterification with diazomethane to give diacid ester 166. Treatment of the latter with TBAF cleaved the TBDMS ether and gave a lactone intermediate

Bifunctional dendrons for multiple carbohydrate presentation via carbonyl chemistry

• Davide Bini,
• Francesco Nicotra and
• Laura Cipolla

Beilstein J. Org. Chem. 2014, 10, 1686–1691, doi:10.3762/bjoc.10.177

• -fucopyranosyloxyamine [18] were used as sample monosaccharides for the conjugation of the dendron (Scheme 1). Synthesis of dendrons Zero, first and second generation heterobifunctional dendrons 1–3 were synthesized starting from 9-decen-1-ol (12) or selected building blocks 13 and 14 (Scheme 2) [11] by esterification

Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

• Andreas Gansäuer,
• Andreas Okkel,
• Lukas Schwach,
• Laura Wagner,
• Anja Selig and
• Aram Prokop

Beilstein J. Org. Chem. 2014, 10, 1630–1637, doi:10.3762/bjoc.10.169

• with classical organic acylation reactions (Friedel–Crafts reaction, esterification, amide synthesis, Scheme 1). Some of these complexes have been used as organometallic gelators [19][20], as a novel class of cytostatic compounds [26], and catalysts for unusual radical cyclizations [27][28][29][30][31

The search for new amphiphiles: synthesis of a modular, high-throughput library

• George C. Feast,
• Thomas Lepitre,
• Xavier Mulet,
• Charlotte E. Conn,
• Oliver E. Hutt,
• G. Paul Savage and
• Calum J. Drummond

Beilstein J. Org. Chem. 2014, 10, 1578–1588, doi:10.3762/bjoc.10.163

• that enabled a late-stage, modular addition of the hydrocarbon chains; the products of which could be taken straight into the high-throughput CuAAC reaction. To this end, diol 2 was synthesised by esterification of commercially available 3-hydroxy-2-(hydroxymethyl)-2-methylpropanoic acid (1), according

A promising cellulose-based polyzwitterion with pH-sensitive charges

• Thomas Elschner and
• Thomas Heinze

Beilstein J. Org. Chem. 2014, 10, 1549–1556, doi:10.3762/bjoc.10.159

• Europe and were used without further treatment. Cellulose phenyl carbonate was prepared by esterification of cellulose, dissolved in N,N-dimethylacetamide (DMAc)/LiCl, applying pyridine and phenyl chloroformate [21]. 1, DS 1.92 (determined by means of 1H NMR spectroscopy after peracetylation), FTIR (KBr

Pd/C-catalyzed aerobic oxidative esterification of alcohols and aldehydes: a highly efficient microwave-assisted green protocol

• Marina Caporaso,
• Giancarlo Cravotto,
• Spyros Georgakopoulos,
• George Heropoulos,
• Katia Martina and
• Silvia Tagliapietra

Beilstein J. Org. Chem. 2014, 10, 1454–1461, doi:10.3762/bjoc.10.149

• enhanced by mild dielectric heating. Furthermore, it is a versatile green procedure which generally enables the isolation of esters to be carried out by simple filtration in almost quantitative yields. Keywords: aerobic oxidation; alcohol; esterification; heterogeneous catalysis; microwaves; Introduction

• metals. Homogeneous and heterogeneous Pd catalysts have been widely used in the selective oxidation of alcohols [36][37]. Most publications have focused on the conversion of alcohol to aldehydes or ketones [38][39]. Several examples of the heterogeneous oxidative esterification of alcohols in the

• versatility of these reactors in promoting reactions with gaseous reagents in a closed cavity [56]. In this present work, we report an efficient Pd/C-catalyzed aerobic oxidative esterification of aldehydes and alcohols in the presence of molecular oxygen in a closed MW reactor. The optimized procedure does

Carbohydrate PEGylation, an approach to improve pharmacological potency

• M. Eugenia Giorgi,
• Rosalía Agusti and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 1433–1444, doi:10.3762/bjoc.10.147

• vitro and in vivo. The best performing of the products, a 40-kDa mono-PEGylated sialic acid-mediated conjugate, exhibited a 5-fold lower affinity which was however compensated by a 23-fold increase of circulation half-life [38]. PEGylation of low-molecular weight carbohydrates: Enzymatic esterification