A Non‐Enzymatic Pathway with Superoxide in Intracellular Terpenoid Synthesis

Non‐C₅‐units terpenoids (norisoprenoids) with an acetonyl group are widely distributed in nature. However, studies on the biosynthesis of norisoprenoids are scarce. Now, the C₃₃ norisoprenoid, (all‐E)‐farnesylfarnesylacetone, was identified from Bacillus spp. and it was elucidated for the first time that superoxide mediates the cleavage of menaquinones (vitamin K) to form norisoprenoids in saponification treatment. From in vivo experiments using gene‐disrupted Bacillus subtilis strains targeted for enzymes responsible for menaquinone biosynthesis and for superoxide dismutase, it was suggested that the non‐enzymatic cleavage (autoxidation) of menaquinone with superoxide resulted in norisoprenoid synthesis in Bacillus cells. Furthermore, the bioactive norisoprenoids, farnesylacetone and phytone, were produced in Bacillus cells by this novel synthesis system.     

Alternative preparation and characterization of platinum(II) organometallic dinuclear complexes and oligomers with 3,8-diethynylphenanthroline derivatives

Novel platinum(II) organometallic dinuclear complexes and oligomers with two types of phenanthroline ligands, namely 3,8-diethynylphenanthroline (L1) and 3,8-bis-(4-ethynyl-phenylethynyl)-1,10-phenanthroline (L2), were synthesized from trans-Pt(PBu₃)₂(1-ethynyl-4-methyl-benzene)Cl and trans-Pt(PBu₃)₂Cl₂ by transmetalation of copper ion. The alternative procedure targeted platinum oligomer termination selection of either chloride or respective phenanthrolines and was successfully performed with different purifications by extraction and column chromatography. The structural formulae of these platinum complexes and oligomers were revealed with by analysis of both ³¹P{¹H}-NMR and ¹H-NMR spectral data. Alternative preparations of platinum oligomers with two types between chloride and respective phenanthroline termination are very useful for the selective synthesis for hybrid polymers with the coupling reaction with two different platinum oligomers with different diethynylaryl ligands. The platinum organometallic compounds showed similar absorption bands in the UV–Vis region. Those prepared with L1 had a strong absorption band at around 400 nm, assignable to the lowest energy metal-perturbed ¹[π–π*] transitions, while in compounds prepared with L2, the strong band appeared around 410 nm, because L2 has an extended π conjugation relative to L1. No distinct differences were observed in the absorption spectra of these platinum oligomers between the different terminal structures, chloride or various phenanthrolines. The luminescence spectra of the platinum compounds prepared with either L1 or L2, however, showed a distinct difference. Those with L1 showed only a phosphorescence assignable to a typical metal-perturbed ³[π–π*] transition with vibronic progressions centered at around 530 nm in deoxygenated CH₂Cl₂ at room temperature, while those with L2 showed weak dual emissions assignable to a mixture of typical metal-perturbed ¹[π–π*] and ³[π–π*] transitions in the visible region.     

The second-generation synthesis of BICMAP analogues

We previously reported the synthesis of BICMAP (1a) via 6-diphenylphosphino-2,3-dihydrobenzofuran as a key intermediate. However, we did not successfully synthesize BICMAP analogues via a similar synthetic route. Herein we report the second-generation synthesis of BICMAP and its derivatives via diethylphosphonate as a key intermediate.     

Determination of residual solvents in pharmaceuticals by thermal desorption-GC/MS.

A novel method for the determination of residual solvents in pharmaceuticals by thermal desorption (TD)-GC/MS has been established. A programmed temperature pyrolyzer (double shot pyrolyzer) is applied for the TD. This method does not require any sample pretreatment and allows very small amounts of the sample. Directly desorbed solvents from intact pharmaceuticals (ca. 1 mg) in the desorption cup (5 mm x 3.8 mm i.d.) were cryofocused at the head of a capillary column prior to a GC/MS analysis. The desorption temperature was set at a point about 20 degrees C higher than the melting point of each sample individually, and held for 3 min. The analytical results using 7 different pharmaceuticals were in agreement with those obtained by direct injection (DI) of the solution, followed by USP XXIII. This proposed TD-GC/MS method was demonstrated to be very useful for the identification and quantification of residual solvents. Furthermore, this method was simple, allowed rapid analysis and gave good repeatability.     

Selective vinyl cationic polymerization of monomers with two cationically polymerizable groups. II. p-vinylphenyl glycidyl ether: An epoxy-functionalized styrene

p-Vinylphenyl glycidyl ether (VPGE), a styrene derivative with an epoxy pendant, was polymerized by various cationic initiators, and its selective vinyl polymerization was investigated at low temperatures below ?15°C. BF₃OEt₂ (a metal halide) and CF₃SO₃H (a strong protonic acid) polymerized both vinyl and epoxy groups of VPGE, and produced cross-linked insoluble polymers. The HI/I₂ initiating system and iodine, in contrast, polymerized its vinyl group in polar solvents (CH₂Cl₂ and nitroethane) highly selectively in the temperature range of ?15 to ?40°C to give soluble polymers with a polystyrene backbone and epoxy pendants; however, under these conditions, 10–15% of the epoxy groups of the polymers were consumed during the polymerization by the reaction with the growing species. The polymerization by HI/I₂ in CH₂CI₂ involved a long-lived propagating species, as indicated by a progressive increase in the molecular weight (M?_n) of the polymers with monomer conversion and their fairly narrow molecular weight distributions (M?_w/M?_n ～ 1.6). The differences between the polymerizations of VPGE and p-isopropenylphenyl glycidyl ether, an α-methylstyrene-type counterpart of VPGE, were also discussed with an emphasis on the effects of the α-methyl group in the latter monomer.     

Detection sensitivity of time interval analysis for the determination of α-radionuclides with millisecond order lifetimes

A selective extraction of the correlated events due to three kinds of short-lived -decay events,²¹⁶Po (145 ms),²¹⁷At (32.3 ms) and²¹⁵Po (1.78 ms), from other random background events were examined by using a time interval analysis (TIA) from the viewpoint of detection sensitivity. In the theoretical treatment based on the probability and statistics, it was clarified that the detection sensitivity proportionally increased with shortening half-lives in the following order,²¹⁵Po>²¹⁷At>²¹⁶Po. In the experiments, pulses from a liquid scintillator owing to -decay events were analyzed using a multiple TIA technique and resulted in the highest sensitivity of²¹⁹Rn–²¹⁵Po pairs in the actinium series. Thus, the multiple TIA method was applied to the practical determination of²¹⁹Rn–²¹⁵Po pairs in natural samples.     

Photocatalytic Activity and Photo-Induced Wettability Conversion of TiO2 Thin Film Prepared by Sol-Gel Process on a Soda-Lime Glass

We have developed the transparent photoactive TiO₂ thin film coated on soda lime glass (SLG) by sol-gel process. Titanium dioxide thin films coated on SLG exhibit lower photocatalytic activity due to the thermal diffusion of Na ion from the SLG substrate. Thin SiO₂ film precoating is very effective to prevent the thermal diffusion of Na ion. We have evaluated the photocatalytic decomposition of gaseous acetaldehyde and the photo-induced surface wettability of TiO₂ films with and without SiO₂ precoating layer. As expected, the TiO₂ film on SiO₂/SLG is more photoactive to decompose acetaldehyde than that on SLG. However, as for wettability conversion, there was little difference in the conversion rate between TiO₂ film without SiO₂, and TiO₂ film with SiO₂. Different dependence of Na ion diffusion on two kinds of photo-induced reaction on TiO₂ is discussed based on the difference of the photo-induced reaction mechanism.