No abstract

The automorphism group of a flag-transitive 6-(v, k, 2) design is a 3-homogeneous permutation group. Therefore, using the classification theorem of 3-homogeneous permutation groups, the classification of flag-transitive 6-(v, k,2) designs can be discussed. In this paper, by analyzing the combination quantity relation of 6-(v, k, 2) design and the characteristics of 3-homogeneous permutation groups, it is proved that: there are no 6-(v, k, 2) designs D admitting a flag transitive group G ≤ Aut (D) of automorphisms.

A concise and chemoenzymatic synthesis of cyctetryptomycin A and B (1-2) using a Zr-catalyst and CttpC is reported. The recent discovery of cyctetryptomycin A and B (1-2) and their intriguing neuroprotective activities necessitated scalable synthesis to facilitate structure-activ-ity relationship studies. However, the synthesis of cyctetryptomycin A and B (1-2) solely by chemical reactions has proven to be impractical. Therefore, a novel approach using a short and chemoenzymatic strategy was developed to prepare cyctetryptomycin A and B (1-2) via Zr-catalyzed construction of two consecutive quaternary chiral carbons and CttpC-catalyzed direct oxidative coupling of the tryptophan moiety.

No abstract