Properties of PTFE tape as a semipermeable membrane in fluorous reactions

• Brendon A. Parsons,
• Olivia Lin Smith,
• Myeong Chae and
• Veljko Dragojlovic

Beilstein J. Org. Chem. 2015, 11, 980–993, doi:10.3762/bjoc.11.110

• chemiluminescence experiment as a qualitative test. The known chemiluminescence reaction of the diaryl oxalate esters oxidized by hydrogen peroxide in the presence of rubrene was investigated (Scheme 2) [38][39][40]. Two solutions were prepared. One solution contained a mixture of diaryl oxalate and rubrene in

• reaction was directional. Only the oxalate–rubrene solution exhibited luminescence during the reaction, regardless of whether it was in the delivery tube or the vial (Figure 11). The peroxide solution remained dark. The reactions with the aqueous peroxide solution proceeded with no change in the column

• height of the oxalate–rubrene solution in the delivery tube (Figure 12), even over an extended period of time. This indicates that solvent transport was not necessarily a requirement for the delivery of the H2O2 reagent. From the directionality of the PV-PTFE chemiluminescence reaction and lack of change

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• cations, allows electrocarboxylation of 1,3-butadiene, and can increase the selectivity for the C6 product (Table 1, entries 5 and 6). The faradaic efficiencies, however, are rather low, hence, there has been a search to find alternative reducing agents. Tetraethylammonium oxalate and formate salts

• reduction and small enough to allow a quick and stable interaction with the cathodically formed carboxylate anions. Furthermore, oxalate and formate are easily oxidized at a Pt anode, gradually releasing the tetraethylammonium cations. The combination of both salts in acetonitrile gives near quantitative

• the organic substrate, but only net conversion of more energetic oxalate and formate. On top of that, it is important to realize that both the MgO and the tetraalkylammonium salts can also be considered as sacrificial reducing agents. Their advantage over sacrificial anodes, however, is an easier

Solid-phase-supported synthesis of morpholinoglycine oligonucleotide mimics

• Tatyana V. Abramova,
• Sergey S. Belov,
• Yulia V. Tarasenko and
• Vladimir N. Silnikov

Beilstein J. Org. Chem. 2014, 10, 1151–1158, doi:10.3762/bjoc.10.115

• -aminohexanoic acid and the application of more active bis(2-cyanoethyl)oxalate instead of dimethyl oxalate. However, only the route shown in Scheme 2 was successful and gave the loading of the polymer with the monomers 5a,d,e close to that of the parent resin. It is interesting that the attachment of the oxalyl

• C15H25N4O5, found, 340.94; [M + Na]+ calcd for C15H24N4NaO5, 363.16; found, 362.96. 6-[N-(2-methoxy-2-oxoacetyl)]aminohexanoic acid (4): A mixture of dimethyl oxalate (1.20 g, 10 mmol), 6-aminohexanoic acid (1.31 g, 10 mmol) and TEA (10 mmol, 1.40 mL) in dry MeOH (20 mL) was stirred at room temperature for

• -protected 2-aminomethylmorpholino nucleosides: i) di-tert-butyl dicarbonate ((Boc)2O), triethylamine (TEA), pyridine (Py); ii) AcOH/H2O. Loading of the Boc-Gly-PAM resin with the morpholino nucleosides 5a,d,e: i) Dimethyl oxalate, TEA, MeOH; ii) 4, TEA, Py; iii) trifluoroacetic acid (TFA)/CH2Cl2/PhSH; iv

Tuning the interactions between electron spins in fullerene-based triad systems

• Maria A. Lebedeva,
• Thomas W. Chamberlain,
• E. Stephen Davies,
• Bradley E. Thomas,
• Martin Schröder and
• Andrei N. Khlobystov

Beilstein J. Org. Chem. 2014, 10, 332–343, doi:10.3762/bjoc.10.31

• 10.3762/bjoc.10.31 Abstract A series of six fullerene–linker–fullerene triads have been prepared by the stepwise addition of the fullerene cages to bridging moieties thus allowing the systematic variation of fullerene cage (C60 or C70) and linker (oxalate, acetate or terephthalate) and enabling precise

• -fullerene spacing. The shorter oxalate-bridged triads exhibit stronger spin–spin coupling with triplet character, while in the longer terephthalate-bridged triads the intramolecular spin–spin coupling is significantly reduced. Keywords: carbon nanomaterials; electrochemistry; EPR; fullerene dimers

• fullerenes are known to be electrochemically stable and can be readily linked together via the N atom to form linear and diastereomerically pure triads. The choice of linker was determined by the target fullerene–fullerene separation in the product, and terephthalate and oxalate bridges were chosen as they

Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

• James C. Anderson,
• Andreas S. Kalogirou,
• Michael J. Porter and
• Graham J. Tizzard

Beilstein J. Org. Chem. 2013, 9, 1737–1744, doi:10.3762/bjoc.9.200

• allow elucidation of the absolute stereochemistry of piperazirum (2). Results and Discussion The common α-keto acid derivative 5 was easily prepared from a Grignard reaction of isobutylmagnesium chloride with diethyl oxalate to give α-keto ester 10 in 94% yield (Scheme 3) [47]. Saponification of 10 with

Self-assembly of Ru₄ and Ru₈ assemblies by coordination using organometallic Ru(II)₂ precursors: Synthesis, characterization and properties

• Sankarasekaran Shanmugaraju,
• Dipak Samanta and
• Partha Sarathi Mukherjee

Beilstein J. Org. Chem. 2012, 8, 313–322, doi:10.3762/bjoc.8.34

• , CD3COCD3) δ 171.65, 140.12, 136.08, 131.62, 129.14, 126.36, 124.65, 101.55, 98.10, 82.85, 81.12, 54.51, 31.56, 22.03, 17.79; IR (neat) ν (cm−1): 3128.8 (w, C=C of aromatic), 1624.6 (s, CO-oxalate), 1254.9 (s, C–F of CF3); ESIMS (m/z): 1907.16 [2a − O3SCF3−]+, 879.0 [2a − 2O3SCF3−]2+; UV–vis (1.0 × 10−5 M

• , 78.00, 31.78, 22.27, 17.70; IR (neat) ν (cm−1): 3128.8 (w, C=C of aromatic), 1521.2 (s, CO-oxalate), 1252.1 (s, C–F of CF3); ESIMS (m/z): 2008.0 [2c − 2O3SCF3−]2+, 1288.0 [2c − 3O3SCF3−]3+, 928.9 [2c − 4O3SCF3−]4+; UV–vis (1.0 × 10−5 M, CH3CN) λmax nm (ε): 293 (6.3 × 104 M−1 cm−1), 499 (3.2 × 104 M−1 cm

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

• cyclisation. However, this problem could be avoided by using an acid-labile oxalate protected hydrazine 104 as depicted in Scheme 23. The yield of this step can be further improved up to 84% if the corresponding calcium oxalate is used. The Bischler–Möhlau reaction is an alternative indole synthesis employing

Studies on Pd/NiFe₂O₄ catalyzed ligand-free Suzuki reaction in aqueous phase: synthesis of biaryls, terphenyls and polyaryls

• Sanjay R. Borhade and
• Suresh B. Waghmode

Beilstein J. Org. Chem. 2011, 7, 310–319, doi:10.3762/bjoc.7.41

• The metal oxalate precursor was prepared by adding 32 mL of a N2 purged solution of NiSO4·6H2O (3.0 g, 0.0114 mol) and FeSO4·7H2O (6.82 g, 0.0228 mol) to the 80 mL of N2 purged (COONH4)2·H2O (3.65 g, 0.0228 mol) with vigorous stirring. The resulting yellowish green suspension was cooled to 0 °C and

Syntheses and properties of thienyl-substituted dithienophenazines

• Annemarie Meyer,
• Eva Sigmund,
• Friedhelm Luppertz,
• Gregor Schnakenburg,
• Immanuel Gadaczek,
• Thomas Bredow,
• Stefan-S. Jester and
• Sigurd Höger

Beilstein J. Org. Chem. 2010, 6, 1180–1187, doi:10.3762/bjoc.6.135

• prepared first 3,3’-thenil (2) by metalation of 3-bromothiophene and reaction with dimethyl oxalate [19]. Subsequent oxidative intramolecular thiophene-thiophene coupling [20] with FeCl3 yielded 3 as a dark red (nearly black) solid. Bromination of 3 with bromine in acetic acid/chloroform gave 4 in nearly