N-[(1R)-1-(4-Chlorophenyl)ethyl]-Cyanamide

The title compound was synthesized by electrophilic cyanation of commercially available (R)-4-chloro-α-methylbenzylamine with cyanogen bromide in diethyl ether, and isolated as a yellow oil in 84% yield. It was characterized by 1H and 13C{1H] NMR, IR, HRMS, and specific rotation measurements.

Modulation of the Biocatalytic Properties of a Novel Lipase from Psychrophilic Serratia sp. (USBA-GBX-513) by Different Immobilization Strategies

In this work, the effect of different immobilization procedures on the properties of a lipase obtained from the extremophilic microorganism Serratia sp. USBA-GBX-513, which was isolated from Paramo soils of Los Nevados National Natural Park (Colombia), is reported. Different Shepharose beads were used: octyl-(OC), octyl-glyoxyl-(OC-GLX), cyanogen bromide (BrCN)-, and Q-Sepharose. The performance of the different immobilized extremophile lipase from Serratia (ESL) was compared with that of the lipase B from Candida antarctica (CALB). In all immobilization tests, hyperactivation of ESL was observed. The highest hyperactivation (10.3) was obtained by immobilization on the OC support. Subsequently, the thermal stability at pH 5, 7, and 9 and the stability in the presence of 50% (v/v) acetonitrile, 50% dioxane, and 50% tetrahydrofuran solvents at pH 7 and 40 °C were evaluated. ESL immobilized on octyl-Sepharose was the most stable biocatalyst at 90 °C and pH 9, while the most stable preparation at pH 5 was ESL immobilized on OC-GLX-Sepharose supports. Finally, in the presence of 50% (v/v) tetrahydrofuran (THF) or dioxane at 40 °C, ESL immobilized on OC-Sepharose was the most stable biocatalyst, while the immobilized preparation of ESL on Q-Sepharose was the most stable one in 40% (v/v) acetonitrile.

Observations of Cyanogen Bromide (BrCN) in the Global Atmosphere during the NASA Atmospheric Tomography mission (ATom) and Implications for Active Bromine Chemistry.

<p>Bromine activation (the production of Br in an elevated oxidation state) represents a mechanism for ozone destruction and mercury removal in the global troposphere, and has been a common feature of both polar boundary layers, often accompanied by nearly complete ozone destruction. The chemistry and budget of active bromine compounds (e.g. Br<sub>2</sub>, BrCl, HOBr) reflects the cycling of Br and ultimately its impact on the environment. Cyanogen bromide (BrCN) has recently been measured by iodide ion high resolution time-of-flight mass spectrometry (I<sup>-</sup> CIMS) during the NASA Atmospheric Tomography mission, and could be a previously unquantified participant in active Br chemistry. BrCN mixing ratios ranged from below detection limit (1.5pptv) up to as high as 48 pptv (10sec avg) and enhancements were almost exclusively confined to the polar boundary layers (PBL). Likely BrCN formation pathways involve the reactions of active Br (Br<sub>2</sub>, HOBr) with reduced nitrogen compounds. Gas phase loss processes due to reaction with radical species are likely quite slow and photolysis is known to be relatively slow. These features, and the lack of BrCN enhancements above the PBL, imply that surface reactions must be the major loss processes. Known liquid phase reactions of BrCN result in the conversion of the Br to bromide (Br<sup>-</sup>) or formation of C-Br bonded organic species, hence a loss of atmospheric active Br from that chemical cycle. Thus, accounting for the chemistry of BrCN will be an important aspect of understanding polar Br cycling.</p>

Oxidative addition of cyanogen bromide to C,N-chelated and Lappert's stannylenes

The process of Br/CN redistribution observed within the (organo)tin(iv) species is displayed as the Pong arcade game.

Improving the Identification and Coverage of Plant Transmembrane Proteins in Medicago Using Bottom–Up Proteomics

Plant transmembrane proteins (TMPs) are essential for normal cellular homeostasis, nutrient exchange, and responses to environmental cues. Commonly used bottom–up proteomic approaches fail to identify a broad coverage of peptide fragments derived from TMPs. Here, we used mass spectrometry (MS) to compare the effectiveness of two solubilization and protein cleavage methods to identify shoot-derived TMPs from the legume Medicago. We compared a urea solubilization, trypsin Lys-C (UR-TLC) cleavage method to a formic acid solubilization, cyanogen bromide and trypsin Lys-C (FA-CTLC) cleavage method. We assessed the effectiveness of these methods by (i) comparing total protein identifications, (ii) determining how many TMPs were identified, and (iii) defining how many peptides incorporate all, or part, of transmembrane domains (TMD) sequences. The results show that the FA-CTLC method identified nine-fold more TMDs, and enriched more hydrophobic TMPs than the UR-TLC method. FA-CTLC identified more TMPs, particularly transporters, whereas UR-TLC preferentially identified TMPs with one TMD, particularly signaling proteins. The results suggest that combining plant membrane purification techniques with both the FA-CTLC and UR-TLC methods will achieve a more complete identification and coverage of TMPs.

Enantioselective Transesterification of Allyl Alcohols with (E)-4-Arylbut-3-en-2-ol Motif by Immobilized Lecitase™ Ultra

Lecitase™ Ultra was immobilized on four different supports and tested for the first time as the biocatalyst in the kinetic resolution of racemic allyl alcohols with the (E)-4-arylbut-3-en-2-ol system in the process of transesterification. The most effective biocatalyst turned out to be the enzyme immobilized on agarose activated with cyanogen bromide (LU-CNBr). The best results (E > 200, ees and eep = 95–99%) were obtained for (E)-4-phenylbut-3-en-2-ol and its analog with a 2,5-dimethylphenyl ring whereas the lowest ee of kinetic resolution products (90%) was achieved for the substrate with a 4-methoxyphenyl substituent. For all substrates, (R)-enantiomers were esterified faster than their (S)-antipodes. The results showed that LU-CNBr is a versatile biocatalyst, showing high activity and enantioselectivity in a wide range of organic solvents in the presence of commonly used acyl donors. High operational stability of LU-CNBr allows it to be reused in three subsequent reaction cycles without negative effects on the efficiency and enantioselectivity of transesterification. This biocatalyst can become attractive to the commercial lipases in the process of the kinetic resolution of allyl alcohols.

Electrochemical N-Demethylation of 14-Hydroxy Morphinans – Sustainable Access towards Opioid Antagonists

The growing demand for opioid antagonists necessitates the development of more efficient and affordable synthetic routes. The most challenging step in the preparation of these essential medicines is the selective N-demethylation of a 14-hydroxy opioid precursor to the corresponding nor-opioid, which is followed by N-alkylation of the resulting secondary amine. This process is carried out on large scales using stoichiometric amounts of hazardous chemicals like cyanogen bromide or chloroformates. We have developed a mild, reagent- and catalyst-free procedure for the N-demethylation step, based on the anodic oxidation of the tertiary amine. The ensuing iminium cation rapidly undergoes cyclization with the 14-hydroxy group, or acyl transfer from its acetylated derivative, resulting in intermediates that can be readily hydrolyzed to the target nor-opioids. The electrochemical method provides excellent yields and has successfully been transferred to a flow electrolysis cell, thus enabling the potential scale-up of this synthetic strategy.

Electrochemical N-Demethylation of 14-Hydroxy Morphinans – Sustainable Access towards Opioid Antagonists

The growing demand for opioid antagonists necessitates the development of more efficient and affordable synthetic routes. The most challenging step in the preparation of these essential medicines is the selective N-demethylation of a 14-hydroxy opioid precursor to the corresponding nor-opioid, which is followed by N-alkylation of the resulting secondary amine. This process is carried out on large scales using stoichiometric amounts of hazardous chemicals like cyanogen bromide or chloroformates. We have developed a mild, reagent- and catalyst-free procedure for the N-demethylation step, based on the anodic oxidation of the tertiary amine. The ensuing iminium cation rapidly undergoes cyclization with the 14-hydroxy group, or acyl transfer from its acetylated derivative, resulting in intermediates that can be readily hydrolyzed to the target nor-opioids. The electrochemical method provides excellent yields and has successfully been transferred to a flow electrolysis cell, thus enabling the potential scale-up of this synthetic strategy.