Cryptoic acids A and B, benzene-containing polyketides, and cyclocryptamide, a modified diketopiperazine, from an actinomycete of the genus Cryptosporangium.

Two new benzene-containing polyketides, cryptoic acids A (1) and B (2), along with a new acylated diketopiperazine designated cyclocryptamide (3), were isolated from the culture extract of Cryptosporangium sp. YDKA-T02. The absolute configuration of amino acid components in 3 was determined by Marfey's method.

Synthesis of α-Boryl-α-Substituted Allylboronates from Propyne.

A novel method for the two-step synthesis of α-boryl-α-substituted allylboronates from propyne is described. These allylboronates are prepared by the Co-catalyzed 1,1-diboration reaction of propyne with Bpin, followed by the base-mediated alkylation reaction of 1,1-di(boryl)propene at the α-position. Computational studies revealed the origins of observed reactivity and selectivity in the base-mediated alkylation reaction.

Sporangimicins A-D, acylated maltose derivatives from a rare actinomycete of the genus Pseudosporangium.

Sporangimicins A-D (1-4), four anomeric pairs of diacyl disaccharides that represent a new metabolite class, were discovered from the culture extract of an actinomycete Pseudosporangium sp. RD061809. Compounds 1-4 caused peak separation in the HPLC chromatogram and partial duplication of the NMR resonances by anomeric interconversion of a maltose core modified at the two sugar 6-positions with an isobutanoyl and a methyl-branched long-chain dienoyl groups.

Allostreptopyrroles A-E, β-alkylpyrrole derivatives from an actinomycete sp. RD068384.

Five new β-alkylpyrrole derivatives, allostreptopyrroles A-E (-), were isolated from the culture broth of RD068384. Their structures were elucidated by 1D and 2D NMR spectroscopic analyses, HRESIMS, and chemical derivatization. The absolute configurations of compounds and were predicted by comparison of experimental and calculated specific rotation data.

Herbidomicins, two pairs of polyketide tautomers produced by an actinomycete of the genus Herbidospora.

Herbidospora is one of the underexplored actinomycete genera from which only a limited number of secondary metabolites are reported. In our continuing investigation on less explored actinomycetes, a liquid culture of Herbidospora sp. RD 11066 was found to contain unknown metabolites that had no match in our in-house UV database.