Release of β-galactosidase from poloxamine/α-cyclodextrin hydrogels

• César A. Estévez,
• José Ramón Isasi,
• Eneko Larrañeta and
• Itziar Vélaz

Beilstein J. Org. Chem. 2014, 10, 3127–3135, doi:10.3762/bjoc.10.330

• systems because biocompatible polymers are gradually absorbed by the body with no need for a subsequent surgical removal. However, these systems can also present some disadvantages depending on the nature of the degradation products, which can be toxic, immunogenic or carcinogenic [15]. In this work, our

Palladium-catalyzed 2,5-diheteroarylation of 2,5-dibromothiophene derivatives

• Fatma Belkessam,
• Aidene Mohand,
• Jean-François Soulé,
• Abdelhamid Elias and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 2912–2919, doi:10.3762/bjoc.10.309

• degradation products. The use of 6 equiv of thiophene allowed the formation of 2,2':5',2"-terthiophene (7) in 85% yield. The reactivity of three furan derivatives was also studied using PdCl(C3H5)(dppb) as the catalyst. From 2-n-butylfuran, 8 was obtained in 79% yield, whereas 2-acetylfuran and methyl 2

• and 15 in 83% and 80% yields, respectively. The four terthiophenes 16–19 were also obtained in satisfactory yields. Again a moderate yield in 20 was obtained in the presence of methyl 2-methylfuran-3-carboxylate due to the formation of degradation products, whereas the reaction with 1-methylpyrrole

A new charge-tagged proline-based organocatalyst for mechanistic studies using electrospray mass spectrometry

• J. Alexander Willms,
• Rita Beel,
• Martin L. Schmidt,
• Christian Mundt and
• Marianne Engeser

Beilstein J. Org. Chem. 2014, 10, 2027–2037, doi:10.3762/bjoc.10.211

• quite a number of different species. Side products, off-cycle resting states, reagent degradation products and impurities of various origins may be present in much higher concentration than the interesting reactive intermediates. Thus, ESI spectra of reacting solutions can be frustratingly complicated

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• general scheme for the photodegradation of RF is presented. Keywords: chemical degradation; degradation products; photodegradation; riboflavin; stability; thermal degradation; Review The study of photo, thermal and chemical degradation in the stability of drugs is one of the most concerned areas in the

• degradation products which could be harmful to the human body. However, not every drug shows similar behavior when exposed to unfavorable conditions, e.g., nifedepine [2] and cyanocobalamin [3] degrade rapidly on exposure to light whereas ephedrine [4] shows a slower rate of photodegradation. Information

• the simultaneous determination of RF and its thermal degradation products and evaluated the kinetics of degradation of RF and the formation of the two degradation products [154]. RF is a crystalline substance that melts in the range of 278–282 °C with decomposition [78][155]. It is stable to heat and

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• potency and selectivity of peptides are of great advantage for drug development [4]. The metabolization leads to non-toxic degradation products, which, combined with their high specificity, goes along with low adverse effects. Furthermore, peptides do not tend to interact with other drugs and exhibit a

Studies on the photodegradation of red, green and blue phosphorescent OLED emitters

• Susanna Schmidbauer,
• Andreas Hohenleutner and
• Burkhard König

Beilstein J. Org. Chem. 2013, 9, 2088–2096, doi:10.3762/bjoc.9.245

• solvents are discussed for the different investigated iridium complexes. Some of the resulting degradation products could be identified by using LC–MS or other analytical techniques. The results show how even small structural changes can have a huge influence on rate and mechanism of the photodegradation

• photostabilities of the red and blue emitter and the solvent effect is therefore negligible. With the overall higher stabilities of compounds that emit green light however, processes associated with CH2Cl2 as the solvent become apparent. LC–MS analysis indeed revealed that the main observed degradation products of

• photodegradation behavior and the observed degradation products individually for each of the emitters. The investigations in CH2Cl2 under both ambient and inert conditions showed the same trend as those in benzene for all complexes. Within the range of measurement accuracy, no differences in the degradation

The Amadori rearrangement as glycoconjugation method: Synthesis of non-natural C-glycosyl type glycoconjugates

• Katharina Gallas,
• Gerit Pototschnig,
• Florian Adanitsch,
• Arnold E. Stütz and
• Tanja M. Wrodnigg

Beilstein J. Org. Chem. 2012, 8, 1619–1629, doi:10.3762/bjoc.8.185

• synthetic use, several steps during the introduction of the amine and the subsequent isomerisation to the ketose are reversible, and furthermore, the product itself can enter the Maillard reaction cascade [9][10] pathway. Consequently, a range of side and degradation products can be formed. In general, the

Influence of cyclodextrin on the solubility of a classically prepared 2-vinylcyclopropane macromonomer in aqueous solution

• Helmut Ritter,
• Jia Cheng and
• Monir Tabatabai

Beilstein J. Org. Chem. 2012, 8, 1528–1535, doi:10.3762/bjoc.8.173

• ). After ozonolytic degradation of 8 in methanol, the disappearance of the protons of the double bond signal at δ 5.6 ppm in 1H NMR spectrum and the appearance of the aldehyde protons at δ 8.5 ppm evidence the effective degradation of copolymer. The Mn of the degradation products amounts to 1.8 × 104 g/mol

Selectivity in C-alkylation of dianions of protected 6-methyluridine

• Ngoc Hoa Nguyen,
• Christophe Len,
• Anne-Sophie Castanet and
• Jacques Mortier

Beilstein J. Org. Chem. 2011, 7, 1228–1233, doi:10.3762/bjoc.7.143

• the assignment of the proton–proton correlations of H7 and the allylic methylene groups. Metalation with s-BuLi/TMEDA complex was less efficient although the reaction did not lead to degradation products (entry 6). Ring/internal lithiations of uridine derivatives with s-BuLi/TMEDA are usually

About the activity and selectivity of less well-known metathesis catalysts during ADMET polymerizations

• Hatice Mutlu,
• Lucas Montero de Espinosa,
• Oĝuz Türünç and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2010, 6, 1149–1158, doi:10.3762/bjoc.6.131

• -catalyzed degradation products of polymers P19, P20, P21, and P22. GPC traces of polymerizations performed with C1 at 80, 100, and 120 ºC. Samples taken at 5 min (―–), 15 min (–), 30 min (– • •), and 120 min (-). DSC traces of ADMET polymers P11 and P12 (Table 1, entries 11 and 12, respectively). Overview

Anthracene functionalized terpyridines – synthesis and properties

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 54, doi:10.3762/bjoc.6.54

• impossible. Irradiation experiments were also carried out on the NMR scale – however, the required reagent concentration (10−5 mol/L for intramolecular cycloadditions) made it impossible to record useful NMR spectra. MALDI-TOF measurements did not indicate any degradation products – the [4 + 4]-cycloadducts

Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• as donor, and subsequently to a Mannich reaction with α-iminoglyoxylate. Supported and heterogeneous catalysis Chiral catalysts and ligands are often expensive and the complete separation of these components from reaction products can frequently be quite challenging. Degradation products and leaching

Ru-catalyzed dehydrogenative coupling of carboxylic acids and silanes - a new method for the preparation of silyl ester

• Guo-Bin Liu and
• Hong-Yun Zhao

Beilstein J. Org. Chem. 2008, 4, No. 27, doi:10.3762/bjoc.4.27

• physical and mechanical properties must be considered for performance in serving the expected function, while degradation rate and degradation products are also very important. Since the lability of a silyl ester linkage is dramatically affected by the substituents attached to the silicon atom, poly(silyl