Reactivity of methyl (3,6-dichloropyridazin-4-yl)acetate towards nucleophiles

Methyl (3,6-dichloropyridazin-4-yl)acetate (II), prepared from methyl (3,6-dihydroxypyrid-azin-4-yl)aeetate (1) by chlurination with phosphorus oxychloride, was used for studies of nucleo-philic displacement reactions and it has been found that only the chlorine atom at position 6 was displaced with hydrazine. With diluted hydrochloric acid both chlorine atoms were displaced with the 6-oxo isomer predominating. By turning the aromatic ring of pyridazine into an o-quinoid system, the chlorine atom at position 3 became mobile. Cyelization of (6-hydrazino-s-triazolo-[4,3-b ]pyridazin-7-yl)acetic acid hydrazide (XIX) gave 6-aminopyrrolo[3,2-e ]s-triazlo[ 4,3-b ]-pyridazm-7(8H)one (XXI).     

Reactivity Ratios of Butyl Acrylates in Radical Copolymerization with Methacrylates

The reactivity ratios of four butyl acrylates versus methyl methacrylate and tert-butyl methacrylate were determined for their radical copolymerization in 2-butanone solution using the Jaacks method. The reactivity ratios values obtained were positively verified by substituting into the Alfrey-Goldfinger equation, yielding correct copolymer composition for a series of samples obtained from different initial mole fractions of the comonomers.     

基于傅里叶级数展开式的有效期权定价方法

A novel option pricing method based on Fourier-cosine series expansion was proposed by Fang and Oosterlee. Developing their idea, three new option pricing methods based on Fourier, Fourier-cosine and Fourier-sine series expansions are presented in this paper, which are more efficient when the option prices are calculated with many strike prices. A series of numerical experiments under different exp-L~vy models are also given to compare these new methods with the Fang and Oosterlee＇s method and other methods.     

Alkaline hydrolysis of 3-methyl-4-nitro-5-styrylisoxazole with Na18OH

The use of enriched Na¹⁸OH in the hydrolysis of 3-methyl-4-nitro-5-styrylisoxazole leads to oxygen-labelled cinnamic acids. Isoxazole ring opening and cleavage of title compound has been investigated.     

Permanganate oxidation of 3-methyl-4-nitro-5-styrilisoxazole: a correction

In contrast with a previous report, permanganate oxidation of the title compound $\text{3}$ gives the nitroisoxazolone $\text{8}$ and not 3-methyl-4- nitroisoxazole-5-carboxylic acid $\text{2}$; a reaction pathway, involving the spirocyclisation of the carboxylate $\text{10}$, is suggested.     

Carbon-13 NMR study of 1-methyl-3-phenyl-4-diazo-5-benzoylamidopyrazole and other model pyrazole compounds

A ¹³C nmr study of a diazo, of two diazonium salts and of some other model pyrazole compounds is reported. It is found that the C-4 diazo carbon is more shielded than the normal sp² pyrazole hybridized carbon, while its diazonium salt is more deshielded. The electron density on the C-4 of the diazopyrazole is probably due to the positive charge on the terminal nitrogen. Thus the ¹³C chemical shift values allowed us to understand the chemical behaviour of a compound of potential antitumor activity.     

Multiple periodic solutions for a nonlinear suspension bridge equation

We investigate nonlinear oscillations in a fourth-order partialdifferential equation which models a suspension bridge. Previouswork establishes multiple periodic solutions when a parameterexceeds a certain eigenvalue. In this paper, we use Leray-Schauderdegree theory to prove that if the parameter is increased further,beyond a second eigenvalue, then additional solutions are created.     

The preparation of arylpropiolic acids via styrylisoxazoles

The vic-dibromo derivatives obtained by bromine addition to 3-methyl-4-nitro-5-styrylisoxazoles were used as starting materials for the preparation of arylpropiolic acids.