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高濃度オゾン水によるノボラック樹脂を主成分とするフォトレジストの除去過程の機構を明らかにした上で，適度の紫外線照射が大きく除去を加速することが見いだされ，除去が二段階の化学プロセスで進むことが明らかとなった．すなわち，（1）紫外線によってオゾンが分解して生じた水酸化物ラジカルがノボラック樹脂のフェノール部を水酸化してポリフェノールに変換する．（2）親電子試薬であるオゾンに対してフェノールより著しく反応性が向上したポリフェノールは，容易にオゾンの酸化分解を受けて高効率フォトレジスト除去を達成する．一方，紫外線が強すぎると，全てのオゾンが光分解するので除去速度は落ちる結果となった．これらの実験事実に基づいてオゾン濃度と紫外線強度のバランスが除去効率を支配することが明らかとなった．

We have synthesized α-(phosphoryl)methyl tetrazolyl sulfoxides and examined the reactivities in the thermolyses and in the presence of several amines, such as aniline, benzylamine, piperidine, pyrrolidine, and morpholine. Thermolyses of the derivatives in the presence of 2,3-dimethyl-1,3-butadiene afforded 2-phosphoryl substituted 4,5-dimethyl-3,6-dihydro-2H-thiopyran S-oxide. In addition, novel phosphinecarbothioamides were obtained in the reaction of the derivatives with amines.

The removal technology of single-wafer processing using ozone is proposed on photoresist stripping in the semiconductor manufacturing in order not to generate residual sulfate group after stripping. It is revealed that Disk-shaped nozzle proposed by the authors forms a vortex structure between the disks which is considered to cause the reduction of photoresist stripping rate. This study proposes a disk-shaped convex nozzle. In order to investigate the effects on the flow caused by the presence or absence of the convex, visualization using a high-speed video-camera and numerical simulation of the flow between the disks were conducted. Also, the stripping experiments were conducted to investigate the effects on the photoresist stripping rate caused by the presence or absence of the convex. As a result, the vortex structure that was observed in the disk-shaped nozzle has been disappeared in the disk-shaped convex nozzle. In addition, it is revealed that disk-shaped convex nozzle has the higher stripping ability than disk-shaped nozzle in the convex part. Next, as a stripping method that is different from the conventional, we suggest the ozone microbubble with a venturi tube. To obtaining knowledge about the performance of the photoresist stripping with the ozone microbubbles, first, the generation of ozone microbubbles is observed in the venturi tube via a high speed video camera. Next, to clarify the effect of the superficial liquid and gas velocities on the ozone water concentration and the photoresist stripping rate, ozone water concentration measurement and photoresist stripping experiments were conducted. As a result, the ozone water concentration with increasing superficial velocity increase and the remaining photoresist thickness reduce. In addition, compared with the existing study, it is suggested that the superficial liquid and gas velocities and ozone water concentration affect the photoresist stripping rate.Copyright © 2015 by JSME

Molecular structures and some properties of starches from propagules of mangrove species, Rhizophora stylosa Griff. (Rs), Kandelia candel (L.) Druce (Kc), and Bruguiera gymnorrhiza (L.) Lamk. (Bg), were examined. Starch content (dry basis, %) of mature propagules was 26.8–33.9. The Rs, Kc and Bg starch showed Ca, Cb and Cc crystalline type, respectively. Pasting properties differed greatly by source especially for Kc starch having the highest peak-viscosity and ∼10 °C lower pasting temperature (68.9 °C). Actual amylose content (%) was 26.3, 24.5 and 22.3 for Rs, Kc and Bg starch. Bg amylose showed number-average degree of polymerization (DPn, determined by a fluorescent labeling method) of 840 while Rs and Kc amyloses showed larger DPn, 2620 and 2200. The mangrove amyloses contained highly branched molecules (average number of chains, 13.8–16.8) with varying proportion (14–57% by mole). DPn of Rs, Kc and Bg amylopectin was 15,700, 15,900 and 11,000, respectively. The Rs amylopectin was characteristic in that the molecular species having medium size (DPn 11,900) predominated (50% by mole). Number-average chain length (20–22) and phosphorus content (126–242 ppm) of the amylopectins were comparable to those of sweet potato amylopectins. The molar ratio of unit chains, (A+B1)/(B2+B3), was considerably different, 5.8–8.5, and the ratios indicated sparse branching of the amylopectins.

Bacteria ingested by a neutrophil are located in phagosomes in which H(2)O(2) is produced through the NADPH oxidase-dependent respiratory burst. Myeloperoxidase (MPO) plays important role in the bactericidal action of phagosomes. MPO catalyses the reaction of H(2)O(2) and Cl(-) to produce HClO. The chemical mechanism behind the bactericidal action of the MPO-H(2)O(2)-Cl(-) system is unclear. Bactericidal action may result from (a) the direct reactions of HOCl with biological components (through amine chlorination) or (b) (1)O(2), formed non-enzymatically from HOCl and H(2)O(2), that mainly works to kill microorganisms through bacterial respiratory chain injury. To answer this question, we developed a Cypridina luciferin analogue (MCLA)-dependent chemiluminescence method to determine the rate of formation of (1)O(2) from a (1)O(2) source at pH 4.5-9.0. Using the MCLA-dependent chemiluminescence method, we found that the rate of formation of (1)O(2) from the MPO-H(2)O(2)-Cl(-) system peaked at pH 7.0. Segal et al. (28) reported that almost all Staphylococcus aureus is killed 2 min after phagocytosis by neutrophils where the phagosomal pH is 7.4-7.75. However, amine chlorination by HOCl did not proceed at pH > 7.0. Moreover, the bactericidal activities of the MPO-H(2)O(2)-Cl(-) system with Escherichia coli at pH 4.5 and 8.0 were paralleled by the rate of formation of (1)O(2). Combining these observations and the results reported by Segal et al., we concluded that (1)O(2) is a major chemical species in the killing of bacteria in neutrophil phagosomes.

Trace metals in the viscera of Turbo marmoratus, a huge conical spire, in the coral reef of Ryukyu Island were analyzed. The highest amount of Zn and Fe was detectable in the midgut gland known to be polluted by saxitoxin. This intestine maintained a considerable amount of Si (higher than Ca) which fluctuated in parallel with the taurine amount. These data suggest that the viscera of the alimentary tract accumulate some metals, especially Zn and Fe.

New fluoroalkyl end-capped co-oligomers containing 8-hydroxyquinolyl segments were prepared by the reactions of fluoroalkyl end-capped co-oligomers bearing isocyanato groups. The solvolysis of p -nitrophenyl propaonate (PNP) in the presence of these fluorinated co-oligomers and the corresponding  co-oligomers was investigated in 3:1 (v/v) aqueous methanol buffer solution (0.05 M phosphate, pH 9.2) at 30°C. A large rate enhancement was observed in the presence of the fluorinated co-oligomers for the solvolysis of PNP as compared with the corresponding non-fluorinated co-oligomers. Therefore, these fluoroalkyl end-capped co-oligomers are of particular interest as new fluorinated biomimetic systems for enzyme catalysts.

Three new caged nitric oxides (NOs)-BNN3, BNN5Na, and BNN5M were tested for biological use. BNNs have a strong ultraviolet (UV) absorption band (lambda(max): 300 nm, epsilon: 13.5 mM(-1) cm (-1)) extended to 420 nm and produce NO upon irradiation with 300-360 nm light in quantum yields about 2. A photoexcited BNN molecule yields two NOs with time constants of less than 10 ns for phase 1 and less than 20 micros for phase 2 at 37 degrees C, suggesting usefulness of BNNs for measuring in vivo and in vitro fast NO reactions. Upon irradiating with UV light, caged nitric oxides-loaded rat aortic strips maintained in a state of active tonic contraction effectively relaxed (3 microM BNN5M loading solution concentration). BNN3 is incorporated in the lipid membrane. BNN5Na, insoluble in organic solvents but water soluble, localizes in the water phase. BNN5M, is muscle-cell-permeable and hydrolysed to BNN5Na to remain in cytosol. BNNs were thermally stable and demonstrated no observable toxicity.

To distinguish the bactericidal action of singlet oxygen (1O2) from hypohalous acids, wild-type and lycopene transformant E. coli strains were exposed to each of the oxidants and then bacterial viability was investigated. 1O2 was generated by chemical and enzymatic systems at pH 4.5. Exposure of wild-type E. coli to 1O2 caused a significant loss of E. coli viability due to inactivation of membrane respiratory chain enzymes by 1O2. This action of 1O2 could be attenuated by lycopene in the bacterial cell membrane. In the lycopene transformant strain of E. coli, inactivation of NADH oxidase and succinate oxidase by hypohalous acids were significantly suppressed, but E. coli viability was unaffected. Based on these findings, we suggest that phagocytic leukocytes produce 1O2 as a major bactericidal oxidant in the phagosome.

The chemiluminescence of the Cypridina luciferin analog, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroirnidazo[1,2-a]pyrazin-3-one (MCLA), with O2 (1Δg) generated by the retro-Diels-Alder reaction of 3-(4′-methyI-l'-naphthyl)-propionic acid endoperoxide was studied in an aqueous solution with pH 7.12 at 37°C. The retro-Diels-Alder reaction occurs with a first-order rate constant of (4.16 ± 0.13) × 10−4/s to quantitatively yield O2 (1Δg) and 3-(4′-methyl-l'-naphthyl (-propionic acid. MCLA consumed equimolar amounts of O2 (1Δg) with a second-order rate constant (6.96 ± 0.27) × 108/M/s to emit light in an aqueous solution with pH 7.12 at 37°C. The chemiluminescence spectrum was identified as the fluorescence spectrum of 2-acetylamino-5-(p-methoxyphenyl)pyrazine (OMCLA), a major chemiluminescence reaction. Chemiluminescence spectra and product yields for MCLA reactions with O21Δg, with O2 (3Σ−g) and with superoxide anion radicals are identical, suggesting that all of these reactions occur via a common MCLA-2-hydrope-roxide intermediate formed by a combination of MCLA radicals and superoxide anion radicals. We have established practical use of NEPO as an O2 (1Δg) source and MCLA as a biological probe for detecting O2 (1Δg).

Little is known about the effectiveness of delta9-tetrahydrocannabinol (THC) and anandamide in blocking mechanical nociception. Even less is known about their antinociceptive efficacy in chronic inflammatory arthritis induced by Freund's complete adjuvant. The hypothesis was tested that THC and anandamide elicit antinociception in the paw pressure test, and that arthritic rats would exhibit a different response. In nonarthritic rats, THC- and anandamide-induced antinociception lasted 90 min and 15 min, respectively, while antinociception lasted 90 min and 30 min, respectively, in arthritic rats. Area under the curve calculations revealed no effect of arthritis on THC- and anandamide-induced antinociception. Another hypothesis was that paw pressure thresholds in arthritic rats reflect chronic cannabinoid receptor stimulation due to elevations in free anandamide levels. Yet, the CB1 receptor antagonist SR141716A failed to alter paw pressure thresholds in either nonarthritic or arthritic rats. Further investigation revealed that SR141716A significantly blocked THC antinociception, with no effect on anandamide. Thus, anandamide's effects did not result from CB1 receptor stimulation, and any potential contribution of endogenous anandamide in arthritis was not revealed. Finally, THC and anandamide appear to release an as yet unknown endogenous opioid, because naloxone significantly blocked their effects. This study indicates that anandamide and THC may act at different receptor sites to modulate endogenous opioid levels in mechanical nociception.

Rates for the reaction between L-S-nitrosocysteine and L-cysteine were found to be first order with respect to concentrations of the two reactants in the pH range of 4.85 – 9.41. The second order rate constant was determined to be 3.10 × 10−2 M−1s−1 at pH = 7.4 at 37 °C. Spontaneous decomposition of L-S-nitrosocysteine proceeded with the first order rate constant, 1.46 × 10−5 s−1 under the same conditions.

Bis-flavins, each of which bears a disulfide linkage in the molecule, have been synthesized as model compounds for dihydronicotinamide dependent disulfide reductase. These flavins were found to be much better catalysts to promote the reduction of dibenzyl disulfide to α-toluenethiol than 3-methyllumiflavin.

Bis-flavins, each of which bears a disulfide linkage in the molecule, have been synthesized as model compounds for dihydronicotinamide dependent disulfide reductase. These flavins were found to be much better catalysts to promote the reduction of dibenzyl disulfide to α-toluenethiol than 3-methyllumiflavin.

Rates of oxidation of various dithiols with 3-methyllumiflavin to afford the corresponding cyclic disulfides have been examined at various pH values in 30% aqueous ethanol at 30°C. 1,3-Propanedithiol, which affords 1,2-dithiolane, has been found to be the most reactive among several dithiols tested in this oxidation. Kinetic results clearly show that highly strained 1,2-dithiethanes are formed as primary products in the oxidation of vic-dithiols with 3-methyllumiflavin.

Self-assembled aggregates of fluoroalkylated end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers selectively immobilize cytochrome c, and immobilized cytochrome c retains its catalytic activity for oxidation of guaiacol with hydrogen peroxide. In contrast, these fluorinated aggregates do not interact at all with horseradish peroxidase, bovine serum albumin, hemin, vitamin B12, or cytochrome c reductase under similar extraction conditions.

Fluoroalkylated end-capped N -(1,1-dimethyl-3-oxobutyl) acrylamide oligomer is a unique host molecule accommodating luminol and potentially enhancing light emission yield in its chemiluminescence with hydrogen peroxide-potassium ferricyanide in an aqueous solution.

We studied biochemically and cytologically the contribution of lysosomal hyrdolytic pathway to glycogen degradation in the striated muscle of diploid (control) masu salmon Oncorhynchus masou. The data were compared with those of triploid masu salmon or mouse skeletal muscle. Acid α-glucosidase activity, when measured using maltose or glycogen as substrate, was about 10 times higher in diploid masu salmon than in mice, but it was 50% lower inversely when 4-methy-lumbelliferyl α-D-glucoside (4MUαG) as substrate. Total phosphorylase activity in masu salmon muscle was about 7-fold lower than that in mouse muscle. The result suggests that lysosomal hydrolytic pathway of glycogenolysis is relatively active in the fish muscle. We observed glycogeno-somes (glycogen-containing autophagic vacuoles) in the masu salmon muscle but not in mouse muscle, mimicking cytology of human glycogen storage disease type II (GSD II) lacking lysosomal acid α-glucosidase. However, the mechanism of the glycogenosome formation in masu salmon muscle cell can not be explained analogically as in GSD II, since acid α-glucosidase activity was not deficient. There was no clear differences in ultrastructure of the muscle cell or biochemical measurements between diploid and triploid masu salmon.

A single intraperitoneal injection of acarbose (400 mg/kg) into rats caused lysosomal accumulation of glycogen in the liver, mimicking the cytological characteristics of human glycogen storage disease type II (Pompe's disease). The animal model is therefore useful for studying the pathogenesis of the disease. In the present study, we applied this model to examine the lysosomal hydrolytic pathway of glycogen in vivo. To quantify the lysosomal glycogen, the lysosome-rich fraction was rapidly prepared from liver homogenate by agglutination in the presence of Ca2+. Then the fraction was treated with alpha-amylase in isotonic medium to remove cytosolic glycogen, followed by transfer to hypotonic conditions in the presence of Triton X-100 to destroy total glycogen. The amount of lysosomal glycogen was calculated from the difference between the glycogen levels measured before and after the treatment under hypotonic conditions, and then it was corrected based on measurements of the intactness (%) of lysosomes and the recovery (%) of the lysosomal marker enzyme (beta NAGase). We observed no measurable lysosomal glycogen in normal liver by this method, and this was confirmed by electron microscopy. After administration of acarbose, the lysosomal glycogen level increased to 2.5 mg/g liver within 2 days, and then decreased gradually at a rate of 0.4 mg/day/g. The accumulation of glycogen in the lysosomes at an initial velocity of 1.5 mg/day/g liver may be considered as the amount of glycogen that would normally be degraded by acid alpha-glucosidase. Therefore, assuming that the liver breaks down about 40 mg glycogen/day/g, we estimated that about 3% of the glycogen would be hydrolyzed by the lysosomal pathway.

This work was done to characterize the structure of a photosynthetic polysaccharide and its metabolizing enzymes in cyanobacteria, which represent a link between bacteria and green plants in evolutionary terms. Filamentous cyanobacteria, occurring in an alkaline hot spring (45–50oC, pH 8.5–9.0) in Kagoshima Prefecture, were morphologically classified in the genera Lyngbya-Phormidium-Plectonema (LPP). We found a thermostable neutral (α-glucosidase with optimum pH 6.5 in the LPP. A polysaccharide isolated from the TCA-soluble fraction of the LPP was characterized as glycogen that resembled animal glycogen in structure. We also recognized the presence of the TCA-insoluble glycogen at 32–38% of the total amount of glycogen, most of which was bound non-covalently to protein and had a similar iodine absorption spectrum to that of the TCA-soluble glycogen.

We examined the viability of Escherichia coli transformants harboring various carotenoids synthesizing genes in a medium containing an enzymatic singlet oxygen generating system, which contained myeloperoxidase, hydrogen peroxide and Br(-) at pH 4.5. Singlet oxygen quenching activities of various carotenoids in phosphatidyl choline micelles in aqueous media were also studied using the same enzymatic singlet oxygen generating system. Viability of the transformants producing carotenoids was higher than that of the wild type E. coli in the singlet oxygen generation mixture. Of the transformants tested, the viability of zeaxanthin-diglucoside producing transformant was the highest. Carotenoids in increasing order of k(q) values were beta-carotene, a cyclic carotene

Biominerals and metals of intertidal corals of two species (Heliofungia actiniformis, Quoy and Gaimard; Galaxea fascicularis, Linnaeus), collected from the Iriomote Island of Ryukyu, were examined with an inductively coupled plasma atomic emission spectrometer (ICP-AES). Twelve elements were detectable in the coralline skeletons dissected radially along the growth axis. The relative content (RC) of Hg periodically fluctuated and was minimum at the hollow sites of the coralline slab of Heliofungia sp., corresponding to the cyclic growth. There were two types of elements: constant elements and variable elements along the growth axis. RCs of Ca, Mg, Al, Si, and P were nearly constant. RCs of Fe, Mn, Cu, and Ba were variable, but not as regularly changed as Hg. There were positive mass correlations of Hg to Mn, Cu and Zn, but not to Ba and Fe. In contrast, these relationships were not prominent and were likely degraded by aging in the skeleton of Galaxea sp., suggesting a different mode from that of the Heliofungia sp.

3-(4'-Methyl-1'-naphthyl)-propionic acid, 1',4'-endoperoxide (NEPO) provides singlet state of oxygen (1O2, 1delta g) at 37 degrees C in sodium phosphate buffer (pH 7.2), acetate buffer (pH 4.5), methanol or chloroform, through the retro-Diels-Alder reaction. The total amount of 1O2 generated by NEPO was calculated using the following equation: [1O2]= [NEPO]0[1-exp(-kt)], where [1O2], [NEPO]0 and k are the total amount of 1O2 produced during the time t, initial concentration of NEPO and the first-order reaction rate constant, respectively. When squalene was exposed to 1O2 which was generated thermolytically from NEPO, it was oxidized to three hydroperoxides, mono-, di- and tri-hydroperoxides, in amounts proportional to the dose of NEPO. The oxidizability of squalene was much more extensive compared with unsaturated phospholipids. Additionally, when wild-type E. coli and lycopene-producing mutant E. coli were exposed to NEPO-derived 1O2, there was significant loss of viability of wild-type E. coli but no significant loss of viability in lycopene-producing strain, suggesting that lycopene by scavenging 1O2 protected E. coli against 1O2 toxicity.

The chemiluminescence of the Cypridina luciferin analogue, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin++ +-3-one (MCLA) was observed at 462 nm in the presence of horseradish peroxidase (HRP) and the total spectrum of light emitted was found to depend linearly on HRP concentration. Methods for the determination of HRP concentration using the chemiluminescence was investigated. HRP could be detected in the range from 100 pmol/L to 100 nmol/L under the optimum condition, H2O2 (10 mmol/L) and MCLA (10 mumol/L) at pH 5.8.

Our study of the kinetics of deprotonation and decomposition of spiro[adamantane-1,3′-(4′-(m-hydroxy-phenyl)-4′-methoxy-1′,2′-dioxetane)] (I) showed kinetic parameters for decomposition of tetrabutylammmonium salt of I to be ΔH‡=85.4±1.1 kJ mol-1; ΔS‡=16.0±3.5 J mol-1 K-1.

The excited triplet state of N,N′-dimethyl-N,N′-dinitroso-p-phenylenediamine (BNN3, λmax: 299 nm), caged nitric oxide (ET: 230 kJ mol−1), was found to readily undergo N–N bond homolysis to release NO. This suggests that by covalently binding a triplet sensitizing chromophore, e.g., biacetyl, to BNN3 N-methyl group, its NO photoreleasing light can be switched from UV to visible, less cytotoxic light, such as 425 nm.

Rates of autoxidation of NAD(P)H initiated by hydroperoxyl radical, the acid form of superoxide anion radical which was generated by xanthine/xanthine oxidase, followed a typical autoxidation kinetic equation. Second-order rate constants for the reactions of NADPH and NADH with hydroperoxyl radical were found to be 9.82 +/- 0.13 x 10(4) M-1s-1 and 9.26 +/- 0.58 x 10(4) M-1s-1 at 25 degrees C, respectively. Rates of the reactions between NAD(P)H and superoxide to give degraded products other than NAD(P)+ were also investigated.

Sunlight was found to strongly induce the formation of Nϵ-(carboxymethyl)lysine (CML) from glycated polylysine in the presence of Fe(III) ion. The initial step of this Fe(III)-catalyzed CML formation was noted to be similar to that of blueprint photography as was confirmed by the production of Turnbull's blue in sunlight-exposed glycated human serum albumin ferricyanide solution in the presence of Fe(III). Based on this, photoinduced oxidative C–C bond cleavage of the Amadori compound was assumed to be initiated by photochemical single electron transfer from ligand to Fe(III) in the Fe(III)–Amadori compound complex affording the Fe(II)–Amadori compound radical intermediate, which eventually yields either CML or active oxygen species. CML is thus a useful oxidative stress marker. The mechanism proposed here would explain the high accumulation of CML in lens protein and skin actinic elastosis.

18 O-Scrambling in carbonyl-18O-labelled phthaloyl peroxide, a cyclic Case III diacyl peroxide, proceeds 42 times faster than its decomposition at 80° C. This is the only diacyl peroxide for which 18O-scrambling takes place faster than the decomposition. The activation parameters have been found to be ΔdH‡= 33.4 ± 0.7 kcal mol–1 and ΔdS‡= 5.9 ± 1.9 cal mol–1 K–1 for decomposition and ΔsH‡= 31.9 ± 0.9 kcal mol–1 and ΔsS‡= 9.5 ± 2.6 cal mol–1 K–1 for 18O-scrambling. The results are best explained in terms of 97.6% of return of the phthaloyloxyl radical intermediate which is generated by homolysis of the O–O bond of the peroxide affording the 18O-scrambled peroxide. Based on this mechanism, the transition state for degradation of the phthaloyloxyl radical intermediate is estimated to be 1.5 kcal mol–1 greater than the recombination. Comparison of the kinetic data for phthaloyl peroxide with those for benzoyl peroxide reported by Martin and Hargis reveals that the extreme thermal stability of phthaloyl peroxide is not due to its cyclic structure which may hinder the O–O stretching vibration, but attributed to the facile phthaloyloxyl radical return. These observations clearly support our postulate concerning the structural effect on the 18O-scrambling of diacyl peroxide which indicates that the recombination of the aroyloxyl radical pair has to overcome a substantial activation energy barrier while a very small activation energy is necessary for aliphatic ones. The present kinetic data are discussed in comparison with those for the Cope rearrangement of 1,4-bis(dideuteriomethylidene)cyclohexane.

Oxygen-18 scrambling in carbonyl-18O-labelled cyclopropanecarbonyl peroxide (CPO) and benzoyl cyclopropanecarbonyl peroxide has been suggested to take place via the recombination of intimate acyloxyl radical pair, based on the following experimental observations. (i) The rate of thermal decomposition of CPO decreased with the increase in the viscosity of hydrocarbon solvent; however, the rate of the 18O-scrambling of CPO in Nujol, a highly viscous solvent, was found to be twice that in hexane. Examination of the effect of solvent viscosity on the rate of the decomposition of CPO by Pryor–Neuman's equation reveals that the 18O-scrambling in CPO takes place almost solely through recombination of the intimate cyclopropanecarboxyl radical pair. In octane, the rate constant for dissociation of the intimate cyclopropanecarboxyl radical pair was estimated to be one order of magnitude greater than those for recombination and decarboxylation of the intimate acyloxyl radical pair. (ii) The enthalpy of activation for the decomposition of CPO was found to be 2.0–2.8 kcal mol–1 greater than that for the 18O-scrambling of CPO in CCl4 which corresponds to the energy barrier for dissociation of the intimate cyclopropanecarboxyl radical pair in the solvent cage. The entropy of activation for 18O-scrambling was found to be small but positive in contrast to the large negative values of entropies of activation for usual concerted sigmatropic rearrangements. (iii) Successive substitution of the cyclopropyl groups of CPO with phenyl groups reduced markedly the rate of the 18O-scrambling in the peroxides. This substituent effect is the same as that in the initial bond breaking type of the Cope rearrangement of homotropylidenes; however, opposite to that is the Cope rearrangements of open chain hexa-1,5-dienes in which a substantial extent of the new bond has been formed in the transition state.

Using the xanthine–xanthine oxidase–O2 system as a continuous superoxide radical anion supplying system, kinetic studies of the chemiluminescence reaction of the Cypridina luciferin analogue (CLA), 2-methyl-6-phenylimidazo[1,2-a]pyrazin-3(7H)-one, with superoxide have been carried out. One mole of CLA appeared to consume two moles of superoxide to emit light in aqueous solution in a pH range 5.5–10.0 under aerobic conditions. Only when the supply of superoxide is very small while the concentration of molecular oxygen is high, was a little contribution of autoxidation of CLA by a chain reaction process observed. A substantial lag in the emission of light after the disappearance of CLA was observed, indicating that the initial reaction of CLA with superoxide is not solely the rate-determining step. Subsequent reactions of intermediates that lead to the final light emitter also contribute to the rate-determining step in this chemiluminescence reaction. The decay of CLA was found to be first order with respect to the concentration of CLA and superoxide from competitive kinetics with superoxide dismutase. From the effect of pH on the apparent second-order rate constant for the decay of CLA, the active species of superoxide that initiates the reaction was found to be the hydroperoxyl radical. The second-order rate constants have been determined to be (7.03 ± 0.59)× 105 dm3 mol–1 s–1 for the reaction with CLA and (2.56 ± 0.40)× 108 dm3 mol–1 s–1 for the reaction with the conjugate base of CLA at 20.0 °C.

Unlike the real enzyme, FAD-containing monooxygenase, 4a-FlEt-OOH, oxidizes most of common primary, secondary and tertiary water-soluble amines, such as N-methylmorpholine and n-octylamine. Both kinetic rates and products of the oxidation were obtained. The plots of the rates vs. pKa values gave three different correlations lines depending upon the types of amines

The enantiotopic differentiating ability of pig liver microsomal FAD-containing mono-oxygenase (EC 1.14.13.8) in the oxygenation of nine unsymmetrical sulphides has been investigated. By this enzymatic oxygenation, the sulphides are converted into the corresponding optically active sulphoxides with varying degrees of enantiomeric excess (96–12%).Three cyclic sulphides have been studied in order to establish the diastereotopic differentiating ability of the enzyme. In the oxygenation of racemic 2-methyl-2,3-dihydrobenzo[b]thiophene both enantiomeric and diastereotopic differentiation appears to take place concurrently with high selectivity. The enantiotopic, diastereotopic, and enantiomeric differentiating abilities of the FAD-containing mono-oxygenase are all higher than those of the phenobarbital-induced rabbit liver microsomal cytochrome P-450.

Treatment of 4,4′-dihaloazoxybenzenes with sulfuric acid afforded 4,4′-dihaloazobenzenes (6) as the major product and 5-halo-2-(p-halophenylazo)phenols, the Wallach rearrangement products as minor products, besides 2-halo-5-(p-halophenylazo)phenols, 2-halo-4-(p-halophenylazo)phenols, and 4-(p-halophenylazo)phenols as abnormal rearrangement products. The reaction of fluoro compound gave the azophenols (3a or 5a) in the best yields. However, the ratio of 3a to 5a was found to vary with the concentration of sulfuric acid. Treatment of 4-haloazoxybenzenes with sulfuric acid gave 4-(p-halophenylazo)phenols and 4-haloazobenzenes (13) as major products together with 2-(p-halophenylazo)phenols and 5-halo-2-(phenylazo)phenols as minor products. Yields of reduction products 6 and 13 increased as the halosubstituent became heavier in the following sequence: F→Cl→Br→I.

meso-Tetraphenylporphinatoiron chloride (TPPFeIIICl) has been found to catalyse the reductive cleavage of semipolar S–O and S–N bonds in aromatic sulphoxides and sulphilimines respectively with both 1-benzyl-1,4-dihydronicotinamide (BNAH) and sodium borohydride. Sulphoxides bearing electron-withdrawing substituents are much more readily reduced than those with electron-donating groups. The rate of reduction by the TPPFeIII/BNAH system decreases in the following order: N-unsubstituted sulphilimines > N-tosylsulphilimines > aromatic sulphoxides. During the reaction with sulphoxides, the formation of the µ-oxo dimer of TPPFeIII has been observed. Under the same conditions, concurrent reductive cleavage of the S–C bond was observed with sulphoxides bearing an electron-withdrawing group at the α-position. Control experiments revealed that the reductive S-dealkylation of these sulphides is accompanied by the major S-deoxygenation reaction. Plausible mechanisms are discussed.

An enzyme model system, consisted with TPPFe(III)Cl/imidazole has been found to catalyze hydrogen peroxide dependent S-oxygenation and oxidative S-dealkylation of organic sulfides. This biomimetic reaction has been compared with the cytochrome P-450 catalyzed H 2 O 2 dependent oxygenation.

Arenesulfonic acids, its sodium salts, and alkyl arenesulfonates were reduced readily to the corresponding arenethiols quantitatively with triphenylphosphine in the presence of iodine.

The reaction between N-tosyldiarylsulfilimines and p-toluenethiolate anion did not take place in the dark even upon heating up to 62° but proceeded smoothly upon irradiation with visible light in DMF at room temperature, affording S-N bond cleavage products.