Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

• Yulia V. Khoroshunova,
• Denis A. Morozov,
• Andrey I. Taratayko,
• Polina D. Gladkikh,
• Yuri I. Glazachev and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

• ; sterically shielded nitroxide; Introduction Sterically shielded nitroxides are currently attracting much attention due to their high resistance to bioreduction [1][2]. It has been demonstrated that 2,2,5,5-tetraethylpyrrolidine nitroxides have the highest stability, sometimes exceeding that of trityl

Synthesis of α,β-unsaturated esters via a chemo-enzymatic chain elongation approach by combining carboxylic acid reduction and Wittig reaction

• Yitao Duan,
• Peiyuan Yao,
• Yuncheng Du,
• Jinhui Feng,
• Qiaqing Wu and
• Dunming Zhu

Beilstein J. Org. Chem. 2015, 11, 2245–2251, doi:10.3762/bjoc.11.243

• reaction mechanism (post-translational phosphopantetheinylation, ATP, Mg2+, and NADPH as cofactors) [27][28][29][30]. As such, we initiated the search for new carboxylic acid reductases and the exploration of their potential as biocatalysts for the efficient bioreduction of carboxylic acids. Herein we

Engineering Pichia pastoris for improved NADH regeneration: A novel chassis strain for whole-cell catalysis

• Martina Geier,
• Christoph Brandner,
• Gernot A. Strohmeier,
• Mélanie Hall,
• Franz S. Hartner and
• Anton Glieder

Beilstein J. Org. Chem. 2015, 11, 1741–1748, doi:10.3762/bjoc.11.190

• an efficient and easy-to-use strategy for NADH-dependent whole-cell conversions. At the same time methanol serves as co-solvent, inductor for catalyst and cofactor regeneration pathway expression and source of energy. Keywords: bioreduction; cofactor regeneration; dihydroxyacetone synthase; methanol

• addition of 250 µL BMM2 (1% (v/v) in methanol) approximately 12 h prior to the start of the bioreduction reaction. The BDH1-mediated bioreduction was started by adding BMM10 (5% (v/v) methanol) containing 250 mM rac-acetoin. After a reaction time of 16 h, 300 µL of the reaction supernatant were extracted

• 12 h prior to the start of the bioreduction reaction. For BDH1 catalyzed acetoin conversion, cells corresponding to 3000 OD600 units were harvested by centrifugation (3000g, 10 min, rt) and resuspended in 50 mL of buffered minimal medium. The reaction was started by adding 10 mL of the substrate