Solid-phase total synthesis and structural confirmation of antimicrobial longicatenamide A

• Takumi Matsumoto,
• Takefumi Kuranaga,
• Yuto Taniguchi,
• Weicheng Wang and
• Hideaki Kakeya

Beilstein J. Org. Chem. 2022, 18, 1560–1566, doi:10.3762/bjoc.18.166

• determined using the modified Mosher’s method [21]. Protection of diol 25 by tert-butyl(dimethyl)silyl (TBS) group followed by selective deprotection of the primary alcohol led to 27. Finally, acid 7 was obtained from alcohol 27 through the same two-step oxidation used to obtain compound 10. Having

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• functional theory (DFT) calculation of the ECD spectrum for 4, for which the absolute configuration was established by the modified Mosher’s method in our previous work [15]. Since the acyltetronic acid exists as a mixture of keto–enol tautomers, the calculation was carried out using the four possible

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• together with 11 known phytochemicals through chromatographic methods. The chemical structure of the new isolate 1 was determined by conventional 1D and 2D NMR data analysis, ECD experiment, hydrolysis followed by a modified Mosher’s method, and LC–MS analysis. The characterized compounds’ biological

• configuration at C-6 was deduced as S (the stereochemical descriptor was flipped from R to S due to an O-glycosylation at C-2, see Figure 2C, right). The 9R configuration of 1 was determined by the modified Mosher’s method [23][24][25]. The hydrolysis product of 1 (1a) was esterified with the Mosher reagents

• . sinensis twigs and their structures were characterized by intensive 1D and 2D NMR data analysis, ECD experiment, modified Mosher’s method, and LC–MS analysis. The 12 phytochemicals were evaluated for their anticancer, antineuroinflammatory, and neurotrophic effects and the active compounds 8–11 could be

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

• Ken-ichi Nakashima,
• Junko Tomida,
• Tomoe Tsuboi,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 2100–2107, doi:10.3762/bjoc.16.177

• configurations were determined using the modified Mosher’s method and through comparisons of experimental and calculated electronic circular dichroism data. In addition, muyocopronone B (2) was found to exhibit a weak antibacterial activity against some Gram-positive bacteria. Keywords: azaphilones; endophytic

• fungus; modified Mosher’s method; Muyocopron laterale; polyketides; Introduction Azaphilones, which are a class of fungal polyketides with diverse structures, have received growing attention due to their various biological activities, such as the inhibition of some protein–protein interactions [1][2

• ′/H-3′ (J = 8.2 Hz) and H-3′/H-4′ (J = 3.2 Hz). To establish the absolute configuration of the side chain, we therefore employed the modified Mosher’s method [21]. Although we initially attempted the preparation of the α-methoxy-α-trifluoromethylphenylacetic acid (MTPA) esters using 1.2 equivalents of

Chemoenzymatic synthesis and biological evaluation of enantiomerically enriched 1-(β-hydroxypropyl)imidazolium- and triazolium-based ionic liquids

• Paweł Borowiecki,
• Małgorzata Milner-Krawczyk and
• Jan Plenkiewicz

Beilstein J. Org. Chem. 2013, 9, 516–525, doi:10.3762/bjoc.9.56

• the alcohols (+)-5a and (+)-5b, obtained by lipase-catalyzed transesterification of the racemates (±)-3a and (±)-3b, were determined by the modified Mosher’s method as described by Riguera et al [57]. This approach consists of comparing the differences between 1H NMR chemical shifts recorded for the