A new tris-annulation reagent prepared from a butadiene telomer,and its application to steroid synthesis

Reaction of 1,7-octadien-3-one with dimethyl malonate, followed by the reduction of the ketone produced dimethyl (3-hydroxy-7-octenyl)malonate, which was converted to 9-decen-5-olide after hydrolysis and decarboxylation. Reaction of vinylmagnesium chloride with the lactone and the subsequent acylation afforded 7-acetoxy-1,11-dodecadien-3-one. This is a new tris-annulation reagent. (±)-D-homo-19-norandrosta-4-en-3-one was synthesized by using this tris-annulation reagent.     

Mössbauer spectra and molecular structure of spin-crossover iron (III) complexes of monoclinic form with hexadentate ligands derived form triethylenetetramine and salicylaldehyde [Fe(sal2trien)]BPh4·acetone

Iron (III) complexes of [FeL]BPh₄·acetone containing the hexadentate ligand derived from triethylenetetramine and salicylaldehyde have been synthesized. These complexes were grown in two crystalline forms; monoclinic and twin crystals. The spin-state interconversion rate of the monoclinic form is as fast as the inverse of the Mössbauer lifetime (1×10^?7 s) above 200 K. The crystal structure of the monoclinic form (complex a) was determined at 290 K and to be of space group P2₁/a, with a=27.418 (4), b=10.097 (2), c=14.726 (3) Å, β=98.00 (1)°, and Z=4. The average bond distances of Fe?O (1.875 Å), Fe?N_imine (1.988 Å) and Fe?N_amine (2.069 Å) are in good agreement with the expected values for the transition spin-state between high- and low-spin states. Twin crystals are in a high-spin state over the temperature range 78–320 K.     

One-carbon extrusion from carbohydrates via C1-alkoxy radical fragmentation. An easy access to erythrose and threose

Generation and fragmentation of the C1-alkoxy radicals of pyranose derivatives are nicely promoted by (diacetoxyiodo)benzene or lead tetraacetate in the presence of iodine catalyst under mild conditions to give the corresponding mixed-acetal formates which are further converted to the furanose derivatives by acid-catalysed transacetalization.     

Detection of extraneous abnormal sounds affecting road traffic noise by use of a necessary condition method

When measuring and/or recording road traffic sound levels during a long time interval, extraneous abnormal sounds will inevitably affect the road traffic sound levels of interest. Such sounds include those produced by horns, sirens, animals, construction sites, and the like. The detection and elimination of such extraneous sound requires much time and effort, but are necessary if noise indices such as L_eq, L_max, and L₁₀ are to be properly estimated. This paper proposes a practical detection method of these extraneous interfering sounds by deriving a necessary condition that road traffic sound levels must satisfy. The necessary condition provides an easy method of identifying sound levels not satisfying the condition, and distinguishes them as extraneous abnormal sounds, even in a large volume of observed data. The validity and usefulness of this method are confirmed by application to actually observed data.     

A synthetic approach to crown ether analogs by the remote photocyclization with a pai system of phthalimide and methylthio groups

Upon irradiation a homologous series of certain phthalimides ($\text{2a}$-$\text{c}$) possessing a terminal sulfide function in their N-poly-ether side chain undergo regioselective remote photocyclization affording seven to fifteen-membered crown ether analogs ($\text{3a}$-$\text{c}$) in moderate yields.     

Optoelectronic logic operations by triangular-barrier optoelectronic switch

Optoelectronic logic operations were successfully demonstrated by triangular-barrier optoelectronic switch (TOPS). TOPS has not only differential gain, bistable and latch characteristics simply by changing the bias voltages, but also high sensitivity and high gain. We first confirmed AND and OR operations using a single TOPS, and also realized NOT, NAND, NOR and XOR operations using dual TOPS without any optical or electrical reset signals. These logic operations by dual TOPS can be attained in the same electrical circuit configuration.     

Structures of modified nucleotides isolated from calf thymus DNA alkylated with reductively activated mitomycin C

The structures of modified nucleotides isolated from calf thymus DNA alkylated with reductively activated mitomycin C were determined.