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. cis-(9S,10S)-Methyl 1-propyl-1,2,3,4-tetra-hydro-β-carboline-3-carboxyl-ate
Samina Alam, Mashooda Hasan, Sadaf Saeed, Andreas Fischer, Naeema Khan Acta Crystallogr Sect E Struct Rep Online. 2008 Jan 4;64(Pt 2):o361. doi: 10.1107/S1600536807066020.
The title compound, C(16)H(20)N(2)O(2), was synthesized from (S)-tryptophan methyl ester hydro-chloride and butyraldehyde. The absolute configuration 9S,10S was assigned on the basis of the unchanging chirality of the C9 centre. The NH group of the indole ring is involved in inter-molecular N-H⋯O hydrogen bonding, while the NH group of the six-membered ring is not. This latter ring has a half-chair conformation.
3. Methyl N-(3-cyano-picolino-yl)-l-tryptophanate
Olga Ovdiichuk, Olga Hordiyenko, Zoia Voitenko, Axelle Arrault, Volodymyr Medviediev Acta Crystallogr Sect E Struct Rep Online. 2013 Nov 23;69(Pt 12):o1810. doi: 10.1107/S160053681303153X.
In the title compound, C19H16N4O3, the stereocenter has an l configuration; l-tryptophan methyl ester hydro-chloride being used as a starting material. The indole ring system and the pyridine ring are inclined to one another by 13.55 (14)°. In the crystal, adjacent mol-ecules are linked via N-H⋯O hydrogen bonds, forming chains propagating along the c-axis direction.
