Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• .13.48 Abstract This comprehensive review describes methods for the preparation of 1-indanones published in original and patent literature from 1926 to 2017. More than 100 synthetic methods utilizing carboxylic acids, esters, diesters, acid chlorides, ketones, alkynes, alcohols etc. as starting materials

• diesters: In 1951, Gilmore has demonstrated that use of esters, rather than free arylpropionic acids in phosphoric acid, in the presence of phosphorus pentoxide also led to 1-indanones in equally good or even better yields [32]. Transition metal complexes have been used by Negishi et al. as catalysts in

Diastereoselective anodic hetero- and homo-coupling of menthol-, 8-methylmenthol- and 8-phenylmenthol-2-alkylmalonates

• Matthias C. Letzel,
• Hans J. Schäfer and
• Roland Fröhlich

Beilstein J. Org. Chem. 2017, 13, 33–42, doi:10.3762/bjoc.13.5

• /b to diesters 26a/b/c–29a/b/c (n.d.: not determined). Reductive cleavage of 30a–c to 8-phenylmenthol (3) and 31a–c. 13C NMR data of compounds 23, 24 and 25. Facial selectivities for 26–29. Comparison of the diastereoselectivity in hetero- and homo-coupling reactions. Supporting Information

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• ], or malonate diesters via Claisen condensations followed by hydrolysis and decarboxylation. The greenest routes appear in the [4 + 2] strategy. The three-step route beginning with photochemical ring opening of cyclobutenone to give vinylketene, followed by Diels–Alder addition to ethylene leading to

Synthesis of medronic acid monoesters and their purification by high-performance countercurrent chromatography or by hydroxyapatite

• Elina Puljula,
• Jouko Vepsäläinen and
• Petri A. Turhanen

Beilstein J. Org. Chem. 2016, 12, 2145–2149, doi:10.3762/bjoc.12.204

• monoesters via dealkylation of medronic acid mixed tetraesters [22]. The synthesis of triesters [23] and symmetrical diesters [24] from medronic acid tetraesters has been achieved previously by using tertiary and secondary amines, for example. Unfortunately the same strategy cannot be applied to the

Solvent-free synthesis of novel para-menthane-3,8-diol ester derivatives from citronellal using a polymer-supported scandium triflate catalyst

• Lubabalo Mafu,
• Ben Zeelie and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 2046–2054, doi:10.3762/bjoc.12.193

• developed, where both hydroxy groups of para-menthane-3,8-diol could be simultaneous acylated under mild reaction conditions to form the corresponding diesters in good yields. The advantages of this method include a simple procedure from natural resources, using solvent-free reaction conditions. Keywords

• : acylation; diesters; para-menthane-3,8-diol; PS-Sc(OTf)3; Introduction Although South Africa has a substantial petrochemical industry, the fine chemical industry is very small and most chemicals are imported. As such there is significant interest in the use of natural resources for the manufacture of added

• presentation of PMD 3 conversion to the desired product at various temperatures. It can be seen on the graph in Figure 1 that the PMD 3 conversion to diesters has its optimum at lower temperatures. When the reaction is operated at 70 °C and above, dehydration of the substrate starts to occur, leading to

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Nucleic acids through condensation of nucleosides and phosphorous acid in the presence of sulfur

• Tuomas Lönnberg

Beilstein J. Org. Chem. 2016, 12, 670–673, doi:10.3762/bjoc.12.67

• phosphorous acid are hydrolytically stable compounds that are readily formed upon concentration of aqueous solutions of alcohols and phosphite salts [12]. The monoesters may react further to H-phosphonate diesters but this is an equilibrium process that under aqueous conditions favors the starting materials

• [13]. Oxidation of the H-phosphonate diester products, however, converts them to the stable phosphodiester counterparts. It is interesting to note that this reaction is faster for H-phosphonate diesters than for the respective monoesters or phosphorous acid itself [12], providing the driving force for

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

• of dicarboxylic acid derivatives. Accordingly, vinyl diesters (1) and trifluoroethyl diesters (2) have been synthesized following standard procedures [16]. Moreover, succinic (3) and glutaric anhydride (4) could be used as acylating agents in controlled biocatalyzed reactions (Scheme 1) [17][18]. b

• diesters More recently, symmetric diesters have been synthetized exploiting both the activated extremities of divinyl carboxylates. C6-dicarboxylic acid diesters derivatives of the thiazoline of N-acetylglucosamine (NAG-thiazoline, 10a,b, Figure 2) were prepared and their inhibitor activities towards

• conditions for enzyme catalysis afforded nice polymers. The obtained polymers could be cross-linked by UV light in the presence of the solid photoinitiator Iracure 270 to form hard films [69]. Several poly(amine-co-ester)s were synthesized directly from dicarboxylic acid diesters and N-alkyl- or N

Synthesis of γ-hydroxypropyl P-chirogenic (±)-phosphorus oxide derivatives by regioselective ring-opening of oxaphospholane 2-oxide precursors

• Iris Binyamin,
• Shoval Meidan-Shani and
• Nissan Ashkenazi

Beilstein J. Org. Chem. 2015, 11, 1332–1339, doi:10.3762/bjoc.11.143

• substituted selectively under milder Grignard conditions to form a single P–C bond, leaving the other ester groups intact [15][16]. Cyclic phosphorus diesters are much more reactive towards nucleophilic reagents than their acyclic analogs. Specifically, 5-membered cyclic esters of phosphonic and phosphoric

Novel stereocontrolled syntheses of tashiromine and epitashiromine

• Loránd Kiss,
• Enikő Forró and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2015, 11, 596–603, doi:10.3762/bjoc.11.66

• intramolecular cyclization of a chiral alkenylated pyrrolidinone, followed by hydroxylation [32], or by the intramolecular ring closure of chiral pyrrolidine diesters followed by ester and oxo group reduction [33], while the syntheses of (+)-epitashiromine starts from a chiral morpholine derivative, with nitrone

Copper-catalyzed cascade reactions of α,β-unsaturated esters with keto esters

• Zhengning Li,
• Chongnian Wang and
• Zengchang Li

Beilstein J. Org. Chem. 2015, 11, 213–218, doi:10.3762/bjoc.11.23

• unsaturated diester followed by a sequential aldol addition and lactonization reaction [13]. To address aforementioned challenges, we have recently reported the first example of a copper-catalyzed reductive aldolization–lactonization cascade reaction of α,β-unsaturated diesters with ketones [14] and imines

• -hydroxy ester after the work-up. After lactonization, the derived methoxide reacted with a silane in a reasonable rate to recover the CuH catalyst. This is in agreement to our previously described copper-catalyzed reductive aldolization–lactonization cascade reaction of α,β-unsaturated diesters with

Synthesis of dinucleoside acylphosphonites by phosphonodiamidite chemistry and investigation of phosphorus epimerization

• William H. Hersh

Beilstein J. Org. Chem. 2015, 11, 184–191, doi:10.3762/bjoc.11.19

• foam, which was assumed to be the color of the desired products due to its similarity to 7 and 9. However, the presence of unreacted 5′-O-DMTr-thymidine, the starting acyls 7 and 9, and downfield 31P NMR peaks that are characteristic of diesters necessitated chromatographic separation. The isolation of

• orange color of the trityl cation was not seen. The diesters were less robust than the precursor monoester amidites. For instance, rapid chromatographic separation of the products from the ammonium salts formed during the synthesis was required to prevent further decomposition. The best procedure was

NAA-modified DNA oligonucleotides with zwitterionic backbones: stereoselective synthesis of A–T phosphoramidite building blocks

• Boris Schmidtgall,
• Claudia Höbartner and
• Christian Ducho

Beilstein J. Org. Chem. 2015, 11, 50–60, doi:10.3762/bjoc.11.8

• to develop oligonucleotide-based drug candidates or biomedical chemical probes [5][6]. Native nucleic acids are connected by phosphate diesters as linking units, thus leading to a polyanionic backbone structure. Implications of this characteristic feature of nucleic acid architecture have been

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

• in moderate to good yields. Lower yields were attributed to steric hindrance of the second and third esterifications, as well as the presence of mono- and diesters making the purification more difficult. 4-Pentynoic acid was used rather than 3-butynoic acid due to the relative price and availability

Syntheses of fluorooxindole and 2-fluoro-2-arylacetic acid derivatives from diethyl 2-fluoromalonate ester

• Antal Harsanyi,
• Graham Sandford,
• Dmitri S. Yufit and
• Judith A.K. Howard

Beilstein J. Org. Chem. 2014, 10, 1213–1219, doi:10.3762/bjoc.10.119

• the diester 3 after the initial SNAr step was not necessary and decarboxylation of crude diester 3 gave 4a very efficiently. Consequently, in all analogous experiments (Table 1), crude product diesters of type 3 were isolated and used without further purification, allowing the ready synthesis of a

Use of activated enol ethers in the synthesis of pyrazoles: reactions with hydrazine and a study of pyrazole tautomerism

• Denisa Tarabová,
• Stanislava Šoralová,
• Martin Breza,
• Marek Fronc,
• Wolfgang Holzer and
• Viktor Milata

Beilstein J. Org. Chem. 2014, 10, 752–760, doi:10.3762/bjoc.10.70

• active methylidene compounds such as diesters, dinitriles of malonic acid or pentane-2,4-dione are excellent three-carbon synthons. They act as trifunctional electrophiles for the syntheses of tautomeric pyrazoles when reacted with hydrazine thereby obtaining 3,4-disubstituted pyrazoles, namely 3-amino

Organobase-catalyzed three-component reactions for the synthesis of 4H-2-aminopyrans, condensed pyrans and polysubstituted benzenes

• Moustafa Sherief Moustafa,
• Saleh Mohammed Al-Mousawi,
• Maghraby Ali Selim,
• Ahmed Mohamed Mosallam and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2014, 10, 141–149, doi:10.3762/bjoc.10.11

• -benzylidenemalononitriles 7b and 7c in the presence of DABCO to yield the corresponding phthalate diesters 37b and 37c (Figure 12). A plausible mechanistic route for the formation of 37a involves an initial addition of DABCO to DEAD to yield the intermediate zwitterionic enammonium diester 34, which then adds to 7a to

• derivatives 13a and 13b (Scheme 6). Although they have potential utility in the field of polymer chemistry, to the best of our knowledge the preparation and chemical reactivity of only a few tetrasubstituted phthalic acid diesters have been described previously. In this effort, we observed that phthalate 37a

Gold(I)-catalyzed enantioselective cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2013, 9, 2250–2264, doi:10.3762/bjoc.9.264

• links the allene and the alkene moieties. Thus, the reaction proved to be efficient for substrates containing tethers with geminal diesters, whereas those containing N-tosyl-based tethers led to significantly lower enantioselectivities. However, the same group more recently demonstrated that a chiral

Damage of polyesters by the atmospheric free radical oxidant NO₃^•: a product study involving model systems

• Catrin Goeschen and
• Uta Wille

Beilstein J. Org. Chem. 2013, 9, 1907–1916, doi:10.3762/bjoc.9.225

• compounds that served in this work as models for substructures typically found in surface-coating polyesters are shown in Figure 1. These comprise aromatic moieties, such as phthalic and benzoic esters 1 and 3, respectively, as well as aliphatic diesters of type 2. The esters were used as methylates or

• neopentylates, where the latter provided a simplified model for diesters of neopentyl glycol, which is the commonly used diol component in such polyesters. All experiments were performed in solution, using two different methods to produce NO3• in situ in the presence of the respective substrate 1–3. In

Preparation of mixed trialkyl alkylcarbonate derivatives of etidronic acid via an unusual route

• Petri A. Turhanen,
• Janne Weisell and
• Jouko J. Vepsäläinen

Beilstein J. Org. Chem. 2012, 8, 2019–2024, doi:10.3762/bjoc.8.228

• ago for carbon backbones [29]. Methyl groups from intermediate 7 (Z = Me, Z’ = H, Na or R) are possibly hydrolyzed either before rearrangement following a similar reaction route reported previously, when P,P-diesters of clodronic acid were prepared from the corresponding triesters by using mesyl

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

Asymmetric Brønsted acid-catalyzed aza-Diels–Alder reaction of cyclic C-acylimines with cyclopentadiene

• Magnus Rueping and
• Sadiya Raja

Beilstein J. Org. Chem. 2012, 8, 1819–1824, doi:10.3762/bjoc.8.208

• with cyclopentadiene providing optically active nitrogen-containing heterocycles (Scheme 1). Results and Discussion Our initial study began with the examination of the the aza-Diels–Alder reaction of cyclic C-acylimine 1 with cyclopentadiene (2) in the presence of BINOL-derived phosphoric acid diesters

• diastereoselectivities under mild reaction conditions. The results reported not only show that chiral BINOL derived phosphoric acid diesters can be efficient catalysts for [4 + 2] cycloadditions involving less-electron-rich dienes but additionally demonstrate the high potential of these acidic Brønsted acids in

Synthesis of oleophilic electron-rich phenylhydrazines

• Aleksandra Jankowiak and
• Piotr Kaszyński

Beilstein J. Org. Chem. 2012, 8, 275–282, doi:10.3762/bjoc.8.29

• deprotection of hydrazides II have been developed (Figure 1). Hydrazides II are efficiently obtained by the addition of organometallic reagents III, prepared from aryl halide IV, to azodicarboxylate diesters (AD) [16][17]. Alternatively, II can be obtained in the Pd(0)- or Cu2+-catalyzed reaction of

Synthesis of novel 5-alkyl/aryl/heteroaryl substituted diethyl 3,4-dihydro-2H-pyrrole-4,4-dicarboxylates by aziridine ring expansion of 2-[(aziridin-1-yl)-1-alkyl/aryl/heteroaryl-methylene]malonic acid diethyl esters

• Satish S. More,
• T. Krishna Mohan,
• Y. Sateesh Kumar,
• U. K. Syam Kumar and
• Navin B. Patel

Beilstein J. Org. Chem. 2011, 7, 831–838, doi:10.3762/bjoc.7.95

• studied. Several novel diethyl 5-alkyl/aryl/heteroaryl-3,4-dihydro-2H-pyrrole-4,4-dicarboxylate derivatives were synthesized using this novel method. We also demonstrated the conversion of these diesters to the corresponding 2-substituted pyrrolines and 2-substituted-4,5-dihydro-3-carbethoxy-pyrroline

The preparation of 3-substituted-1,5-dibromopentanes as precursors to heteracyclohexanes

• Bryan Ringstrand,
• Martin Oltmanns,
• Jeffrey A. Batt,
• Aleksandra Jankowiak,
• Richard P. Denicola and
• Piotr Kaszynski

Beilstein J. Org. Chem. 2011, 7, 386–393, doi:10.3762/bjoc.7.49

• malonate diesters, while tetrahydropyrans 3c and 3d were obtained from tetrahydro-4H-pyran-4-one. The advantages and disadvantages of each route are discussed. Dibromides 1c and 1d were used to prepare sulfonium zwitterions 11c and 11d. Keywords: 1,5-dibromopentanes; heterocycles; methodology; synthesis

• propyl (1a), pentyl (1b), 2-(4-trans-pentylcyclohexyl)ethyl (1c), or 4-propylphenethyl (1d) substituents (Figure 2). We investigate the preparation of appropriate diols 2 starting from malonate (Method 1B, Scheme 1) and glutaconate diesters (Method 1C) as well as appropriate tetrahydropyrans 3 via Wittig