ESR investigations of burnt soil

Electron spin resonance (ESR) of transition metal ions (Mn^2?, Fe³⁺), radiation induced centres and pyrolytically formed radicals was studied to distinguish between burnt and unburnt soil. A testfire place and samples from an archaeological site were analyzed. The concentration of radiation induced centres decreases and pyrolytically formed radicals appear in a thermal annealing experiment. The spectral pattern of iron and manganese resonances changes during the heating process. These signals are useful to estimate temperature and atmosphere of the heating event. Chemithermoluminescence (CTL) of the soil was studied and could reveal its thermal history, too.     

Enzymatic synthesis of flavin adenine dinucleotide

A new and simple enzymatic method for the synthesis of flavin adenine dinucleotide (FAD) from flavin mononucleotide by the transadenylylation reaction using microbial cells is described. Among various microorganisms tested,Artherobacter globiformis IFO 12138 and two soil bacteria were selected as useful enzyme sources. Under suitable reaction conditions, the amount of FAD synthesized was 2.25 μmol/mL with cells ofA. globiformis. The transadenylylation reaction could be coupled with the ATP supplying system through a glycolysis process with yeast.     

Surface-enhanced raman scattering (SERS) of adsorbed molecules on smooth surfaces of metals and a metal oxide

Surface-enhanced Raman spectra were observed for pyridine adsorbed on Ni, Pd and Pt (vacuum evaporated films) as well as on Ag and Au. The υ_o dependence varied remarkably from metal to metal. SERS of pyridine adsorbed on nickel oxide (cleaved single crystal) was also observed. Langmuir films of stearic acid on Ag showed no feature of SERS.     

2,6-Bis(benzoxazoyl)pyridine (bzpybox) as a new dialkylammonium cation receptor

2,6-Bis(2-benzoxazoyl)pyridine (bzpybox) ligand is reported as a new artificial receptor for secondary dialkylammonium.     

Properties of nylon 6 anionically obtained with NaAl(Lac)4 catalyst and polymerization of ϵ-caprolactam with NaAl(Lac)3(OEt) catalyst

The m-cresol-insoluble polymer of ?-caprolactam obtained with NaAl(Lac)₄ catalyst is converted to a soluble polymer on treatment with dilute (0.1 wt-%) aqueous hydrochloric acid without any accompanying degradation of polymer chain. Aluminum contained in the polymer was not removed completely by extensive extraction with methanol, regardless of the solubilities of the polymers. This fact suggests the existence of two forms of aluminum in the polymer: one contributes to insolubility of the polymer and the other does not. The polymerization behavior in the case of NaAl(Lac)₃(OEt) was somewhat different from that of NaAl(Lac)₄ and of NaAl(Lac)₃(NHBu). These results are considered to reflect a difference in the stability of the Al-O, Al-(Lac), and Al-N bonds in the catalyst.     

Reaction of ethyl 3-ethoxymethylene-2,4-dioxovalerate and ethyl ethoxymethyleneoxaloacetate with 3-aminopyrazole analogs. Synthesis and chemistry of 3,6,7-trisubstituted pyrazolo[1,5-a]pyrimidine derivatives

The chemical reactivity of a series of 3-substituted-6-acetyl-7-carbethoxypyrazolo[l,5-a]pyrimidines ( 6a,b,c ) and 3-substituted-6,7-dicarbethoxypyrazolo[1,5-a]pyrimidines ( 7a,b,c ), prepared by the condensations of the 3-aminopyrazole analogs ( 3a,b,c ) with ethyl 3-ethoxymethylene-2,4-dioxovalerate ( 1 ) or ethyl 3-ethoxymethyleneoxaloacetate ( 2 ), was investigated. Catalytic hydrogenation of 6 or 7 afforded 4,7-dihydro derivatives ( 8 or 9 ). Treatment of 6a,b with acetic acid and water underwent ring transformation into 6H-pyrazolo[1,5-a][1,3]diazepin-6-ones ( 17a,b ). By treatment with phenylhydrazine compounds of type 6 underwent cyclization to yield 2H-dipyrazolo[1,5-a:4′,3′-e]pyrimidines ( 18a,b,c ). Compounds 6 or 7 were treated with an excess of diazomethane at room temperature to give 5-methyl-6H-cyclopropa[5a,6a]pyrazolo-[1,5-a]pyrimidines ( 24 and 25 ) in excellent yields. However, when this reaction was carried out under ice cooling, only compounds of type 23 were isolated. Reaction of 6a with ethyl diazoacetate is also described.     

Asymmetric epoxidation catalyzed by novel azacrown ether-type chiral quaternary ammonium salts under phase-transfer catalytic conditions

Asymmetric epoxidation of (E)-chalcone with alkaline hydrogen peroxide by novel chiral phase-transfer catalysts (chiral PTCs) with quaternary ammonium salts of azacrown ether proceeded in high yield and good enantioselectivity. Remarkably, this reaction depended on the length of the carbon chain on the nitrogen atom with the chiral PTCs and on the bulk of the base.