A novel approach to oxoisoaporphine alkaloids via regioselective metalation of alkoxy isoquinolines

• Benedikt C. Melzer and
• Franz Bracher

Beilstein J. Org. Chem. 2017, 13, 1564–1571, doi:10.3762/bjoc.13.156

• reaction conditions. As an alternative reagent for the acylation of arenes with esters Eaton’s reagent (phosphorus pentoxide, 7.7 wt % in methanesulfonic acid) has been described in the literature [28][29]. Eaton’s reagent has advantages over polyphosphoric acid as it is an easy to handle, non-viscous and

Chemical systems, chemical contiguity and the emergence of life

• Terrence P. Kee and
• Pierre-Alain Monnard

Beilstein J. Org. Chem. 2017, 13, 1551–1563, doi:10.3762/bjoc.13.155

• phosphorus (P) in +5 oxidation state, is puzzling to some extent as this element is today a limiting nutrient for life [42]. But the prebiotic availability of P is now being far better understood [43][44][45]. In addition, the reactivity of phosphate and polyphosphate is low in aqueous media in the absence

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• strategy may be utilized, but the stepwise linear approach proceeding from the 3´- to the 5´-terminus of ON is nowadays almost exclusively exploited [1][2]. The coupling reaction may take place either at oxidation level III or V of phosphorus. Owing to higher reactivity of P(III) centers, appropriately

• derivatives 2-ethyl- and 2-benzylthiotetrazole [8] or 4,5-dicyanoimidazole [9]. The activator has a dual role donating a proton to the departing dialkylamino group and attacking as an anionic species on phosphorus [10]. Nucleoside H-phosphonates are, in turn, converted in situ to reactive mixed anhydrides

Phosphorus pentasulfide mediated conversion of organic thiocyanates to thiols

• Chandra Kant Maurya,
• Avik Mazumder and
• Pradeep Kumar Gupta

Beilstein J. Org. Chem. 2017, 13, 1184–1188, doi:10.3762/bjoc.13.117

• /bjoc.13.117 Abstract In this paper we report an efficient and mild procedure for the conversion of organic thiocyanates to thiols in the presence of phosphorus pentasulfide (P2S5) in refluxing toluene. The method avoids the use of expensive and hazardous transition metals and harsh reducing agents, as

• required by reported methods, and provides an attractive alternative to the existing methods for the conversion of organic thiocyanates to thiols. Keywords: dithiocarbamate; phosphorus pentasulfide; thiocyanate; thiol; toluene; Introduction Thiols constitute an important group of sulfur-containing

• -reductive conditions (Scheme 1). Phosphorus pentasulfide (P2S5), a commercially available reagent, has widely been employed in organic synthesis for numerous applications [18]. The synthetic protocol described in this paper makes use of this reagent to provide an efficient and single step procedure for the

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

• 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

Structure–efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds

• Sophie Letort,
• Michaël Bosco,
• Benedetta Cornelio,
• Frédérique Brégier,
• Sébastien Daulon,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2017, 13, 417–427, doi:10.3762/bjoc.13.45

• organophosphorus compound into p-nitrophenol compared to IBA alone. Compound 2 was the most effective, while the slowest pesticide hydrolysis was observed in the presence of derivative 3. These results provided evidence that the relative position of the reactive group towards the phosphorus atom and the vicinity

• paraoxon while IBA alone displayed a generally lower and similar efficiency towards these three pesticides. This suggests that the electrophilic character of the phosphorus atom plays a role in the detoxification process (methyl parathion versus methyl paraoxon). Moreover, the strength and depth of the

• vicinity of the imidazole substituent to the active group confirmed its benefit to accelerate the soman degradation [33]. However, many parameters are involved in the detoxification process. It is known that an aromatic group attached to a phosphorus atom can interact with the cyclodextrin cavity wherefore

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

• Anastasia S. Kostyuchenko,
• Tatyana Yu. Zheleznova,
• Anton J. Stasyuk,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2017, 13, 313–322, doi:10.3762/bjoc.13.34

• the obtained diacylated hydrazines 14b–g were in the range of 58–74% (Scheme 3). Finally, heating the diacyl hydrazines 14b–g in phosphorus oxychloride led to the formation of the desired 1,3,4-oxadiazoles 15b–g. The product yields were between 65–94% after purification by column chromatography

A novel method for heterocyclic amide–thioamide transformations

• Walid Fathalla,
• Ibrahim A. I. Ali and
• Pavel Pazdera

Beilstein J. Org. Chem. 2017, 13, 174–181, doi:10.3762/bjoc.13.20

• ; for instance, Lawesson's reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane 2,4-disulfide) [1][2][3], Berzelius reagent [4][5][6] (P4S10), and phosphorus pentasulfide [7] in dry toluene, xylene or pyridine under reflux conditions. A two-step approach for the purpose of thiation of

First DMAP-mediated direct conversion of Morita–Baylis–Hillman alcohols into γ-ketoallylphosphonates: Synthesis of γ-aminoallylphosphonates

• Marwa Ayadi,
• Haitham Elleuch,
• Emmanuel Vrancken and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2906–2915, doi:10.3762/bjoc.12.290

• has been reported through a palladium-catalyzed hydrogenation of α-fluorovinylphosphonates [43]. In continuation of our interest [21] in the construction of carbon–phosphorus bonds using both cyclic and acyclic MBH adducts, we report herein, for the first time, a direct and facile access to γ

New syntheses of (±)-tashiromine and (±)-epitashiromine via enaminone intermediates

• Darren L. Riley,
• Joseph P. Michael and
• Charles B. de Koning

Beilstein J. Org. Chem. 2016, 12, 2609–2613, doi:10.3762/bjoc.12.256

• Carius tube at 250 °C, affording alcohol 5 in 81% yield. The subsequent protection of the primary alcohol as acetate 6 (87% yield), followed by thionation with phosphorus pentasulfide using the Brillon procedure [29] afforded thiolactam 3 in 90% yield. The succeeding Eschenmoser reaction with α

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

• -butoxide anion and acetophenone (227). These steps occur presumably in a concerted manner. Finally, the protonation of the tert-butoxide anion results in the formation of tert-butanol (228). As alternative bases Et3N [338][339], phosphorus ylides [340] and LiOH [341][342] can be used and the Kornblum

Rh-Catalyzed reductive Mannich-type reaction and its application towards the synthesis of (±)-ezetimibe

• Motoyuki Isoda,
• Kazuyuki Sato,
• Yurika Kunugi,
• Satsuki Tokonishi,
• Atsushi Tarui,
• Masaaki Omote,
• Hideki Minami and
• Akira Ando

Beilstein J. Org. Chem. 2016, 12, 1608–1615, doi:10.3762/bjoc.12.157

• phosphorus pentoxide directly before use, respectively. All imines were prepared from corresponding aldehydes and amines. Methyl acrylate was distilled directly before use. Other commercially available reagents were used without further purification. All experiments were carried out under an argon atmosphere

Dinuclear thiazolylidene copper complex as highly active catalyst for azid–alkyne cycloadditions

• Anne L. Schöffler,
• Ata Makarem,
• Frank Rominger and
• Bernd F. Straub

Beilstein J. Org. Chem. 2016, 12, 1566–1572, doi:10.3762/bjoc.12.151

• structure of hexafluorophosphate salt 1b (CCDC 1472789). Color code: black carbon, grey hydrogen, yellow sulfur, blue nitrogen, magenta phosphorus, green fluorine. Time-conversion-diagram of the CuAAC reaction of benzyl azide with either phenylacetylene or ethyl propiolate in the presence of copper complex

Enantioselective addition of diphenyl phosphonate to ketimines derived from isatins catalyzed by binaphthyl-modified organocatalysts

• Hee Seung Jang,
• Yubin Kim and
• Dae Young Kim

Beilstein J. Org. Chem. 2016, 12, 1551–1556, doi:10.3762/bjoc.12.149

• properties [5], enzyme inhibition [6], peptide mimetic function [7], and herbicidal properties [8]. Since the biological activity of α-aminophosphonate derivatives is dependent upon the chirality of the α-position to the phosphorus atom, asymmetric synthesis of α-aminophosphonates has received considerable

Microwave-assisted synthesis of (aminomethylene)bisphosphine oxides and (aminomethylene)bisphosphonates by a three-component condensation

• Erika Bálint,
• Ádám Tajti,
• Anna Dzielak,
• Gerhard Hägele and
• György Keglevich

Beilstein J. Org. Chem. 2016, 12, 1493–1502, doi:10.3762/bjoc.12.146

• ]. (Aminomethylene)bisphosphonates can also be obtained starting from amides, triethyl phosphite and phosphorus oxychloride (Scheme 3a) [37], or in the reaction of amines with diazophosphonate in the presence of a rhodium catalyst (Scheme 3b) [38]. (Aminomethylene)bisphosphine oxides are analogous to (aminomethylene

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• similar binding poses with respect to the positions of the oxygens linked to the phosphorus atom (strong ionic interactions with the magnesium ion), the ribose moiety (formation of hydrogen bonds between the hydroxy groups and Lys215) and the triazole ring oriented towards the hydrophobic residues Phe157

Ring-whizzing in polyene-PtL₂ complexes revisited

• Oluwakemi A. Oloba-Whenu,
• Thomas A. Albright and
• Chirine Soubra-Ghaoui

Beilstein J. Org. Chem. 2016, 12, 1410–1420, doi:10.3762/bjoc.12.135

• space the groups around the phosphorus atoms have been removed. COT and C8F8 have a tub shaped structure with D2d symmetry [53][54]. As expected an η2 structure, 28, was found to be a minimum. A 1,4-diyl minimum was also found where there are two Pt–C σ bonds, 30. This structure has also been suggested

• with their relative energies in Figure 12. Here again the hydrogens and ethano-bridge connected to the phosphorus atoms has been removed for clarity. We find that the η2 structure, 40, to be the ground state. A low energy η3 transition state, 41, at 7.7 kcal/mol serves to equivalence the top and bottom

• are the two optimized structures of C3H3–Pt(dpe)+. Two unoccupied MOs for Cp+ are shown on the left side. The two stationary points for Cp–Pt(dpe)+ are given by 13 and 14. To conserve space the groups around the phosphorus atoms have been removed. The half-filled degenerate π orbitals in

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

• Svetlana V. Vasilyeva,
• Vyacheslav V. Filichev and
• Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

• phosphorus of the terminal phosphate (Figure 9, insert). Attempts to eliminate this residue by treatment with aqueous 25% ammonia have not been successful. However, it was shown later that this residue does not prevent the subsequent CuAAC reactions with the azido-containing molecules. In view of these

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• . As shown in this review, they play an important role in organophosphorus chemistry where phosphorus reagents are used as substrates for the synthesis of a wide range of phosphorylated heterocycles. In this article, an overview about multicomponent reactions used for the synthesis of heterocyclic

• compounds bearing a phosphonate group on the ring is given. Keywords: multicomponent reactions; organophosphorus chemistry; phosphorus reagents; phosphorylated heterocycles; Introduction Heterocyclic rings are found in many naturally occurring compounds and they compose the core structures of many

• were obtained which were sterically too crowded for attacking the phosphorus atom of the phosphonates. The use of unsymmetrically substituted diamines led to the corresponding syn-regioisomers as the major product and the anti-regioisomer as the minor product. Some of the synthesized 1,5-benzodiazepin

Synthesis, fluorescence properties and the promising cytotoxicity of pyrene–derived aminophosphonates

• Jarosław Lewkowski,
• Maria Rodriguez Moya,
• Anna Wrona-Piotrowicz,
• Janusz Zakrzewski,
• Renata Kontek and
• Gabriela Gajek

Beilstein J. Org. Chem. 2016, 12, 1229–1235, doi:10.3762/bjoc.12.117

• -yl)methyleneamine [17], a N-(1-pyrene)methylideneglucosamine mercury complex [18], a N-(pyren-1-ylidene)-2-hydroxyaniline-copper(II) and -zinc(II) complexes [19] or N-(pyren-1-ylidene)-4-carboxyaniline-Fe(II) and -Cr(III) complexes [20]. Several phosphorus-supported ligands containing a pyrene-1

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• electrophilic nature of the desired allylic halides (viz. use of allylic chloride and 10 mol % sodium iodide in Scheme 9) we opted to transform 1° alcohols (E)-66 and (Z)-67 into their corresponding allylic bromides (not shown). This was straightforward and efficient using phosphorus tribromide in ether at 0 °C

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

• Vladislav Vasilenko,
• Torsten Roth,
• Clemens K. Blasius,
• Sebastian N. Intorp,
• Hubert Wadepohl and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83

• hydrogenations [1][2] and allylic substitutions [3][4] to Heck reactions [5] and conjugate additions to enones [6]. Their popularity arises from the inherent electronic disparity of the phosphorus and the nitrogen donor groups, rendering one binding site a soft π-acceptor featuring a pronounced trans effect and

• . In addition, the resulting ligand families should provide nitrogen and phosphorus donors with varying donor strength (amidine vs imine, phosphine vs heteroatom-bound phosphorus) and different bite angles (five- vs six-membered chelate rings). Results and Discussion Ligand synthesis We based the

• and 3a–c that can exist in solution, depending on the orientation of the phosphorus lone pair, the geometry of the C=N double bond and the orientation of the substituents of the C–N single bond [12]. Notably, all synthesized derivatives feature a single signal in the 31P NMR spectrum at room

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

• nucleic acid polymerizations described so far have utilized activated starting materials, such as cyclic phosphates [1][2] or phosphoroimidazolides [3][4]. The trivalent phosphorus atom of phosphorous acid is much more susceptible to a nucleophilic attack than the pentavalent phosphorus atom of phosphoric

• acid [5]. Furthermore, phosphite salts are up to 1000-fold more soluble in water than phosphate salts [6]. For these reasons, compounds of reduced phosphorus (i.e., phosphorus at oxidation state lower than +5) were first proposed to have played a role in prebiotic phosphorylation reactions as early as

• 1955 [7]. Since then, both terrestrial [8] and extraterrestrial [9] sources of reduced phosphorus have been identified. Recent studies suggest the presence of significant amounts of phosphite in the Archean ocean, lending support to the idea of prebiotic phosphite chemistry [10][11]. Monoesters of

Aluminacyclopentanes in the synthesis of 3-substituted phospholanes and α,ω-bisphospholanes

• Vladimir A. D’yakonov,
• Alevtina L. Makhamatkhanova,
• Rina A. Agliullina,
• Leisan K. Dilmukhametova,
• Tat’yana V. Tyumkina and
• Usein M. Dzhemilev

Beilstein J. Org. Chem. 2016, 12, 406–412, doi:10.3762/bjoc.12.43

• efficient one-pot process for the synthesis of 3-substituted phospholanes and α,ω-bisphospholanes was developed. The method involves the replacement of aluminium in aluminacyclopentanes, prepared in situ by catalytic cycloalumination of α-olefins and α,ω-diolefins, by phosphorus atoms on treatment with

• organophosphorus compounds (OPC) is the direct transformation of five-membered metallacarbocycles based on transition metals to phosphacarbocycles on treatment with phosphorus dihalides. For example, a method for the direct conversion of zirconacyclopentenes [1][2][3][4] and zirconacyclopentadienes [5] to

• substituted phospholenes [6] and phospholes [7] has been reported. This approach was used to obtain materials for light-emitting diodes (LEDs) [8], phosphorus-containing polymers [9][10], bisphospholes [11], bicyclodiphospholanes and spirobicyclodiphospholanes [12][13]. However, this method is faced with some

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

• Sophie Letort,
• Sébastien Balieu,
• William Erb,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

• organophosphorus (NOPs) share a typical structure with a pentavalent phosphorus atom linked to a leaving group (LG), two substituents (R1 and R2) and an oxygen or a sulfur atom (Figure 1), explaining the wide structural diversity of organophosphates. They can be classified into three categories depending on the

• radius whereas the β- and γ-CDs’ primary alcohols cones are similar. The guest molecule’s inclusion depth corresponds to the distance from the phosphorus atom to the secondary OH rim. As this distance is the highest with γ-CD, diazinon (5, Figure 3) is more deeply inserted [47]. According to these

• in the mode of inclusion. For instance, aromatic ring as substituent of the phosphorus atom are often included into the cavity, while steric hindrance is able to impair the complex formation. Finally, without aromatic groups, the mode of entry of the pesticide depends on the specific affinity of the