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Two stereoisomers of penazetidine A (1a), the azetidine alkaloid isolated from the Indo-Pacific marine sponge Penares sollasi, were synthesized by starting from (S)-serine and (R)-or (S)-citronellol. The natural penazetidine A must be either (2S,3R,4S,12′R)- or (2S,3R,4S,12′S)-1a.

The structure of the antibacterial sesquiterpene from Premna oligotricha was shown to be not 1 but 2 (relative stereochemistry) by the unambiguous synthesis of both (±)-1 and (±)-2.

A diastereomeric mixture and the four stereoisomers of 2,6-dimethyloctane-1,8-dioic acid (2), a copulation release pheromone of the cowpea weevil, Callosobruchus maculatus, were synthesized. The stereoisomeric purities of the four synthetic isomers of 2 were determined by the HPLC analyses of their bis-2-(2,3-anthracenedicarboximide)-1-cyclohexyl esters.

The heterothallic species of the agricultural pest Phytophthora use mating hormones α1 and α2 to regulate their sexual reproduction. Here we describe the absolute stereostructure of the second mating hormone α2 as defined by spectroscopic analysis and total synthesis. We have uncovered not only the interspecies universality of α hormones but also the pathway by which α2 is biosynthesized from phytol by A2-mating type strains and metabolized to α1 by A1 strains.

Communication among microorganisms is mediated by secretion and detection of microbial signaling molecules such as quorum-sensing pheromones and microbial hormones. The molecules elicit the regulation of important genes necessary for microbial survival and often play important roles in interspecies or even inter-kingdom communication. Recent progress in the study of the signaling molecules has enabled us to eavesdrop on microbial conversations to gain insight on their intercellular communication system. This review summarizes the recent advances in the chemistry and chemical biology of these important microbial signaling molecules: acyl-homoserine lactones (AHLs), AI-2, CAI-1 related α-hydroxy ketones (AHKs), ComX pheromones, diffusible signal factors (DSFs), diffusible extracellular factor (DF), and Phytophthora mating hormones.

(E)-6-Ethyl-2,10-dimethyl-5,9-undecadienal was identified from female seed beetle, Callosobruchus rhodesianus (Pic), as an electroantennographic-detection (EAD) active compound in the male. The ratio of the (E)-6-ethyl-2,10-dimethyl-5,9-undecadienal and (3S,6E)-2,3-dihydrohomofarnesal, previously identified as a sex attractant pheromone, was estimated at approximately 1:4.5. In combination with the stereoisomer-activity relationship of 2,3-dihydrohomofarnesal, we suggest that this new compound might function as a minor sex attractant pheromone in C. rhodesianus.

Phytocassane A–E possess ent -cassane skeleton because synthetic (+)-2-deoxyphytocassane A with cassane skeleton showed the Cotton effects positive at 369 nm (due to the ring-C dienone chromophore) and negative at 289 nm (due to the ring-A carbonyl group), while the natural phytocassane A exhibited the opposite Cotton effects.

The first synthesis of a stereoisomeric mixture of hormone α1, the mating hormone of Phytophthora , was achieved, and the synthetic mixture was confirmed to be hormonally active.

Both the enantiomers of incrustoporin (2-p-tolyl-2-hexen-4-olide, 1) were synthesized by starting from methyl p-tolylacetate (2) and (S)-1,2-epoxybutane (3). The naturally occurring compound 1 was shown to possess the R configuration.

Vialinin A, a small compound isolated from the Chinese mushroom Thelephora vialis, exhibits more effective anti-inflammatory activity than the widely used immunosuppressive drug tacrolimus (FK506). Here, we show that ubiquitin-specific peptidase 5/isopeptidase T (USP5/IsoT) is a target molecule of vialinin A, identified by using a beads-probe method. Vialinin A inhibited the peptidase activity of USP5/IsoT and also inhibited the enzymatic activities of USP4 among deubiquitinating enzymes tested. Although USPs are a member of thiol protease family, vialinin A exhibited no inhibitions for other thiol proteases, such as calpain and cathepsin.

The first example of immobilized bakers' yeast mediated reduction of ketones in fluorous media is described. The use of fluorous media permits simple work-up and reuse of the solvent without any purification.

The first total synthesis of ent-cassa-12,15-diene, a putative precursor of diterpene phytoalexins, was accomplished.

The four stereoisomers of small bacteriocin, an autoinducer of the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum, were synthesized via a versatile methodology for 3′-hydroxyacyl homoserine lactones based on the Nagao asymmetric aldol reaction. The synthetic isomers were much less effective at inhibiting the growth of R. leguminosarum RBL5523 than the natural isomer, showing the importance of stereochemistry for activity.

An efficient and stereoselective synthesis of three stereoisomers of the sex pheromone of the cowpea weevil, Callosobruchus maculatus, is reported.

An important biological event in phytopathogens of the genus Phytophthora is sexual reproduction, which is conducted by two mating types, A1 and A2. A factor known as hormone alpha1 is secreted by the A1 mating type and induces the formation of sexual spores (oospores) in the A2 mating type. Here we describe the asymmetric synthesis and assignment of the absolute configuration of hormone alpha1 by oospore-inducing assays of the synthesized isomers.

The stereoisomeric composition of the copulation release pheromone of the azuki bean weevil, Callosobruchus chinensis L., was determined to be R:S = 3.3–3.4:1 by the 2D-Ohrui–Akasaka method.

A versatile methodology for the synthesis of various terpenoids via B -alkyl Suzuki–Miyaura coupling as a key step is established. Synthesis of cordiaquinone J and K, new antifungal and larvicidal meroterpenoids, was achieved by using this methodology. The absolute configurations of cordiaquinone J and K were confirmed by the synthesis.

The first example of immobilized bakers' yeast mediated reduction of ketones in fluorous media is described. The use of fluorous media permits simple work-up and reuse of the solvent without any purification.

Summary We have isolated and characterized a cDNA encoding a novel diterpene cyclase, OsDTC1, from suspension-cultured rice cells treated with a chitin elicitor. OsDTC1 functions as ent-cassa-12,15-diene synthase, which is considered to play a key role in the biosynthesis of (−)-phytocassanes recently isolated as rice diterpenoid phytoalexins. The expression of OsDTC1 mRNA was also confirmed in ultraviolet (UV)-irradiated rice leaves. In addition, we identified ent-cassa-12,15-diene, a putative diterpene hydrocarbon precursor of (−)-phytocassanes, as an endogenous compound in the chitin-elicited suspension-cultured rice cells and the UV-irradiated rice leaves. The OsDTC1 cDNA isolated here will be a useful tool to investigate the regulatory mechanisms of the biosyntheis of (−)-phytocassanes in rice.

Total synthesis of cordiaquinone K, a new antifungal and larvicidal meroterpenoid, is reported. The absolute configuration of cordiaquinone K was confirmed by the synthesis.

A novel pyrrolidine amide (MQ-A3) isolated from the tropical convolvulaceous species was synthesized in 5 steps by starting from commercially available 12-bromododecanol and (S)-2-methylbutylbromide. The absolute configuration of the natural product was confirmed by a comparison of the specific rotation values.

The Ohrui-Akasaka method is the only one methodology to solve the intrinsic problem of diastereomer method. The Ohrui-Akasaka ester discriminates an asymmetric center remote from up to 24 carbons. The gauche effect combined with CH-π interaction of the ester sets anthracene ring close to acyl side chain. The distinctive conformation provides a chiral field to a remote asymmetric center. This review describes the examples of the determination of the absolute configuration of the natural products, leustroducsin B, S 365 A and plakoside A, by using the Ohrui-Akasaka method.

Tumor necrosis factor alpha (TNF-α), a central mediator of the inflammatory response, is released from basophilic cells and other cells in response to a variety of proinflammatory stimuli. Vialinin A is a potent inhibitor of TNF-α production and is released from RBL-2H3 cells. Ubiquitin-specific peptidase 5 (USP5), a deubiquitinating enzyme, was identified as a target molecule of vialinin A and its enzymatic activity was inhibited by vialinin A. Here we report production of TNF-α is decreased in USP5 siRNA-knockdown RBL-2H3 cells, compared with control cells. The finding of the present study strongly suggests that USP5 is one of the essential molecules for the production of TNF-α in RBL-2H3.