Synthesis of 6H,8H-isoquino[2,3-c][1,3]benzothiazin-8-ones

6H,8H-Isoquino-1,3-benzothiazin-8-ones have been prepared by reaction of 6,7-dimethoxy-2H-1,3-benzo-thiazines with homophthalic anhydride and by photocyclization of 3-benzoyl-4-methylene-6,7-dimethoxy 2H-1,3-benzothiazine. The compounds are thia analogues of protoberberine alkaloids containing a sulfur atom at C-5 and a lactam function at C-8. The mass spectra of the title compounds are discussed.     

Zinc-mediated carbon radical addition to glyoxylic imines in aqueous media for the synthesis of alpha-amino acids

The addition of carbon radicals to glyoxylic imines was studied using zinc dust as a radical initiator. The zinc-mediated radical reaction of glyoxylic oxime ethers and hydrazones proceeded smoothly to give the alkylated products via a carbon-carbon bond-forming process in aqueous media. The reaction of the oxime ethers and hydrazones having an Oppolzer's camphorsultam group provided the corresponding alkylated products, which could be converted into enantiomerically pure alpha-amino acids. The diastereoselectivities observed in the reaction of hydrazones were better than those obtained in the reaction of oxime ethers.     

Synthesis of highly water soluble C60 end‐capped vinyl ether oligomers with well‐defined structure

Highly water soluble [60]fullerene (C₆₀) end‐capped vinyl ether (VE) oligomers with well‐defined structure were synthesized by living cationic polymerization technique. The addition reaction between 1‐octynylfulleride anion and oligomeric cationic species of VEs with pendant acetoxyl or malonic ester functions afforded the precursor C₆₀ end‐capped oligomers. The living VE oligomers were prepared by living cationic polymerization of diethyl 2‐(vinyloxy)ethylmalonate (VOEM) and 2‐acetoxyethyl vinyl ether (AcOVE) by the CH₃CH(OR)Cl/ZnI₂ [R = CH₂CH₂OCOCH₃ and CH₂CH₂CH(COOEt)₂, respectively] initiating system. The precursors were obtained as dark brown gummy solid in 33 and 72% yield for AcOVE and VOEM, respectively. UV‐vis and ¹³C NMR spectroscopy indicated the formation of 1,2‐disubstituted dihydrofullerene derivatives. Hydrolysis of the precursors proceeded quantitatively to give the water‐soluble C₆₀ end‐capped oligomers having oligo(sodium 2‐vinyloxyethylmalonate) [oligo(VOEMNa)] and oligo(2‐hydroxyethyl vinyl ether) [oligo(HOVE)] moieties. Solubility measurements revealed the water‐soluble C₆₀ end‐capped oligomer with oligo(VOEMNa) chain to have the excellent aqueous solubility compared to that of the water‐soluble C₆₀ derivatives thus far known; the maximum solubility in water is 96.6 mg/mL, which corresponds to 25.9 mg/mL of the C₆₀ moiety. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3578–3585, 2000     

Synthesis and properties of O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl cellulose

In this article, a series of O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl celluloses with different degree of substitution (DS) values was synthesized by a homogeneous reaction of cellulose with 2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl chloride in a 10% (w/w) dimethylacetamide/lithium chloride solution, combined with pyridine as the acid acceptor. The total DS values of the derivatives in anhydroglucose units was determined by ¹H and ¹³C NMR spectra, and ranged from 0.4 to 3.0, depending on the amount of acid chloride in the reaction. The effects of the total DS values and the O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl substituent distribution on the solubility of the derivatives were investigated. The lowest limit of the DS value for water‐soluble O‐2‐[2‐(2‐methoxyethoxy)ethoxy]acetyl cellulose was approximately 0.5, which is lower than that of methylcellulose. The amphiphilic derivatives with higher DS values than 1.7 exhibited a good solubility in both water and organic solvents, such as dimethyl sulfoxide, tetrahydrofuran, and chloroform. Sol‐gel transition in aqueous solution was observed for the amphiphilic derivatives with a higher DS value than 1.7; the precipitation temperature (T_p) decreased as the DS value increased, showing that the derivatives are highly temperature sensitive. The thermal properties of the fully substituted derivative were measured using polarized microscopy, DSC, and X‐ray diffraction; and are discussed in terms of phase transition of the sample derivatives. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 376–382, 2001     

The spectral profile of light scattered by particles in electrophoretic movement

The electrophoretic movements of polystyrene latex particles suspended in water and in electrolyte solutions have been investigated with an optical beating technique. When two kinds of particles in water move in the presence of an external electric field, it is observed that the laser light scattered by these particles exhibits a shifted spectrum with a single peak profile, even if the electrophoretic mobilities of the two kinds of particles are different to each other. However, when these particles are suspended in an electrolyte solution, two separate spectral lines are observed which correspond to the velocity of each kind of particles.     

A locally most powerful invariant test for the equality of means associated with covariate discriminant analysis

In this paper, the authors propose a locally most powerful invariant test for the equality of means in the presence of covariate variables. Also the null and nonnull distributions associated with the above test are developed. This problem arises in covariate discriminant analysis and has been treated by various authors, notably Cochran and Bliss 1948, Ann. Math. Statist.19, 151–176 and Rao 1949, Sankhyã9 343–366; 1966. The test derived here locally dominates in power the tests proposed so far. It is also shown that the Cochran-Bliss test is uniformly most powerful in the class of conditional invariant tests.     

A stable dialkylphosphinyl radical

Dialkylphosphinyl radical 1 was synthesized as thermally stable yellow crystals and found to be monomeric both in solution and in the solid state. EPR spectrum showed that the spin density of 1 is mainly localized on the 3p orbital of the dicoordinated phosphorus atom. A distinct absorption band due to the electronic transition from nonbonding electron pair orbital to singly occupied 3p orbital on the phosphorus atom of 1 was observed at 445 nm in solution. Phosphinyl radical 1 underwent facile reaction with carbon tetrachloride, hydrogen abstraction, and a unique reaction with a persistent radical, galvinoxyl, giving a cyclic phosphaalkene and a silylether.