Beilstein J. Org. Chem.2023,19, 133–138, doi:10.3762/bjoc.19.13
established by comparison of optical rotation values with synthetically prepared authentics. Compound 1 inhibited the growth of Bacillus subtilis and Staphylococcus aureus at MIC of 50 μg/mL and 100 μg/mL, respectively.
Keywords: antibacterial; cyanobacterium; edible; monoacylglycerol; Nostochopsis lobatus
ethanolic extract of this alga and found that a mid-polar fraction inhibited the growth of two Gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus. Activity-guided fractionation led to the discovery of a new monoacylglycerol, nostochopcerol (1, Figure 1). Part of this study have been
reason for the low yield of compound 1 was eventually understood after it was determined to be a monoacylglycerol, which has a surface-active property and should have deteriorated the separation capacity of the chromatographic resins.
The molecular formula of compound 1 was established to be C19H34O4
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Graphical Abstract
Figure 1:
Structure of nostochopcerol (1) and selected COSY (bold lines) and HMBC (arrows) correlations.
Beilstein J. Org. Chem.2019,15, 811–817, doi:10.3762/bjoc.15.78
catalysts such as iron(III) chloride or bismuth(III) triflate was reported. However, the implementation of these protocols in the ball mill only led to trace amounts (less than 5% yield) of the protected monoacylglycerol 4a. Finally, one of the well-established Jacobsen catalysts for the epoxide ring
Information File 1). Analysis of the reaction mixture by 1H NMR revealed that the epoxide ring-opening had occurred preferentially to give sn-1,3-protected monoacylglycerol 4a over its regioisomer counterpart sn-2,3-protected monoacylglycerol 4a’ (4a/4a’ 3.6:1; for details, see Supporting Information File 1
). However, purification of 4a by column chromatography on SiO2 favored acyl migration in 4a, thereby dropping the yield of 4a by increasing the amount of the isomeric sn-2,3-protected monoacylglycerol 4a’ (Figure 2) [42]. Typically, cobalt complex (S,S)-cat has been used for kinetic resolution of racemic
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Graphical Abstract
Figure 1:
Biologically relevant molecules made, used or derivatized by mechanochemistry.