1. Asymmetric Total Synthesis of Griseofamine B and Its Three Stereoisomers
Tao Sheng, Caiyun Ma, Guangyan Zhang, Xuan Pan, Zhanzhu Liu J Nat Prod. 2022 Apr 22;85(4):1128-1133. doi: 10.1021/acs.jnatprod.2c00069. Epub 2022 Mar 3.
The first total synthesis of griseofamine B is described starting from l-4-bromo tryptophan methyl ester hydrochloride via five steps and in 18% overall yield. Its three stereoisomers were also synthesized following the same procedure with the yields of 5%, 19%, and 5%, respectively. In vitro antibacterial activities were also evaluated. All four compounds exhibited less potent activity than griseofamine A.
2. l-Alanine methyl ester hydro-chloride monohydrate
Martin Lutz, Arie Schouten Acta Crystallogr Sect E Struct Rep Online. 2011 Feb 9;67(Pt 3):o586. doi: 10.1107/S160053681100420X.
The enanti-opure title compound, C(4)H(10)NO(2) (+)·Cl(-)·H(2)O, forms a two-dimensional network by inter-molecular hydrogen bonding parallel to (010). Non-merohedral twinning with a twofold rotation about the reciprocal c* axis as twin operation was taken into account during intensity integration and structure refinement. This twinning leads to alternative orientations of the stacked hydrogen-bonded layers.
