Immobilization of trichordema reesei by radiation polymerization

Immobilization of trichordema Reesei (QM9414) was prepared by radiation polymerization. It was found that the activity of fixed cells increased with inseasing surface area of the carrier and was affected by the concentration of monomer tetraethylenglycol dimethacrylate (4G) and the shape of the substrate composition and structure of cotton textile fabics.     

Coupling of focused laser pulse to surfaces of transparent materials studied by time-resolved imaging technique

Short and intense laser pulse can process the surface and the inside of transparent materials by focusing the pulse at the desired position. Here we report the interaction of fundamental radiation (1064 nm) of the Q-switched Nd:YAG laser to the surface of PMMA as observed by an imaging system with nanosecond time resolution. The system used fundamental radiation of a Q-switched Nd:YAG laser as a processing laser and second harmonic radiation (532 nm) of another Nd:YAG laser as illuminating light. We observed shock waves which propagate into the material and into the atmosphere by shadowgraph and photoelastic method. Surface roughness of a sample is expected to affect the coupling of light and transparent materials for both normal and focused laser light. Our results have revealed the effects visually. For roughness larger than 0.6 m, all energy is absorbed at the surface, while the larger part of the energy is absorbed inside the material as the surface becomes smoother. PACS 52.38.MF; 79.20.DS; 87.63.Lk     

Highly stereoselective synthesis of functionalized beta,beta-di- and trisubstituted vinylic sulfoxides by Cu-catalyzed conjugate addition of organozinc reagents

beta,beta-Disubstituted chiral vinylic sulfoxides bearing functionalities have been synthesized via Cu-catalyzed conjugate addition of organozinc reagents to chiral 1-alkynyl sulfoxides. Due to the availability of functionalized organozinc reagents and high syn-selectivity of the reaction, both geometric beta,beta-disubstituted vinylic sulfoxides were selectively synthesized. Furthermore, 1-alkynyl sulfoxides were derivatized into trisubstituted vinylic sulfoxides by trapping the resulting alpha-sulfinyl vinylic carbanion with electrophiles. Highly diastereoselective THF and THP ring formations were accomplished by means of this methodology followed by an intramolecular Michael addition.     

Stereodivergent and reiterative synthesis of bistetrahydrofuran ring cores of annonaceous acetogenins

Eight diastereoisomers of the bistetrahydrofuran ring cores of annonaceous acetogenins have been synthesized by asymmetric alkynylation of alpha-tetrahydrofuranic aldehydes and stereodivergent one-pot tetrahydrofuran (THF) ring formation. In all cases, the asymmetric alkynylation proceeded with very high diastereoselectivity to give eight kinds of optically pure THF cores. We also describe a comparison of the (1)H and (13)C NMR spectral data of the eight isomers and give full details of the THF ring construction.     

Pd-catalyzed sulfinylzincation of activated alkynes with 1-alkynyl sulfoxides as a sulfinyl source

Unprecedented Pd-catalyzed sulfinylzincation with 1-alkynyl sulfoxide as a sulfinyl source was developed. Bis-sulfinyl alkenes were formed in good yields on treatment of 1-alkynyl sulfoxides with Et(2)Zn in the presence of a Pd-catalyst, wherein zinc sulfenate (or sulfinylzinc) species would be generated in situ to undergo highly syn-selective conjugate addition to the 1-alkynyl sulfoxides. By using 3,3-dimethyl-1-butynyl sulfoxides, formation of the bis-sulfinyl alkenes was completely suppressed and the sulfinylzincation of activated alkynes was accomplished. The reaction tolerates various functionalities, and was promoted considerably by the neighboring group participation of the heteroatom at the delta-position in the alkynoates. Stereodivergent synthesis of two diastereomeric vinylic sulfoxides and reaction of the resulting vinylzinc species with electrophiles were also described.     

Diastereoselective Ni(0)-catalyzed carbocyclization to chiral vinylic sulfoxide

Diastereoselective Ni(0)-catalyzed carbocyclization of enone to chiral vinylic sulfoxide has been accomplished, wherein two stereogenic centers were constructed simultaneously to give cis- and trans-disubstituted cyclopentanes from (E)- and (Z)-vinylic sulfoxides, respectively.     

Systematic synthesis of Bis-THF ring cores in annonaceous acetogenins

Systematic synthesis of bis-THF ring cores, synthetic intermediates of adjacent bis-THF annonaceous acetogenins, has been achieved by asymmetric alkynylation and subsequent stereodivergent THF ring formation. The asymmetric alkynylation of alpha-tetrahydrofuranic aldehyde with (S)-3-butyne-1,2-diol derivatives gave good yields of erythro- and threo-adducts with very high diastereoselectivity. These adducts were converted into four types of bis-THF cores via two kinds of one-pot THF ring formation. [reaction: see text]     

Geometrically selective synthesis of functionalized beta,beta-disubstituted vinylic sulfoxides by Cu-catalyzed conjugate addition of organozinc reagents to 1-alkynyl sulfoxides

[reaction: see text] A new synthetic method of chiral beta,beta-disubstituted vinylic sulfoxides bearing various functionalities has been developed by employing Cu-catalyzed conjugate addition of an organozinc reagent to chiral 1-alkynyl sulfoxide. Since the reaction proceeds with very high syn-selectivity, both geometric beta,beta-disubstituted vinylic sulfoxides were stereoselectively synthesized by changing the combination of 1-alkynyl sulfoxide and the organozinc reagent.     

Radical-initiated homo- and copolymerizations of methacryloyl fluoride

The kinetics of methacryloyl fluoride (MAF) homopolymerization was investigated in methyl ethyl ketone (MEK) with azobis(isobutyronitrile) as initiator. The rate of polymerization (R_p) followed the expression R_p = k[AIBN]^0.55[MAF]^1.18. The overall activation energy was calculated as 74.4 kJ/mol. The relative reactivity ratios of MAF(M₂) copolymerization with styrene (r₁ = 0.083, r₂ = 0.14), and methyl methacrylate (r₁ = 0.48, r₂ = 0.81) in methyl ethyl ketone were obtained. Application of the Q–e scheme (in styrene copolymerization) led to Q = 2.22 and e = 1.31. The glass transition temperature (T_g) of poly(MAF) was 90°C by thermomechanical analysis. Thermogravimetry of poly(MAF) showed a 10% weight loss of 228°C in air.     

Effect of calcium ions on the irradiation induced inactivation of cellulase

Abstract The activity of cellulase irradiated at various temperatures was examined as a function of irradiation dose. The effect of calcium ions in radiation inactivation of cellulase at irradiation temperature of 30°C was studied by using calcium sulfate. The calcium ions have a protective ability against radiation caused inactivation of cellulase by scavenging species such as OH(-) formed by irradiation of cellulase aqueous solution, in which the effective concentration range of the calcium ions was ～ 10(-3) M. The calcium ions do not act for the heat inactivation of the enzyme and the enzyme hydrolysis of filter paper or chaff as an activator because the calcium ions do not associate with the enzyme to form a calcium ion-enzyme complex.