Intramolecular double michael reaction III Stereoselective chiral synthesis of atisiran-15-one

Atisiran-15-one (5) was stereoselectively synthesized starting from the ketone (10) through the intramolecular double Michael reaction.     

A novel synthesis of benzo- and indolo[a]quinolizidines by intramolecular diels-alder reaction of l-azadienes

Intramolecular Diels-Alder reaction of l-azadienes was conducted by heating the α,β-unsaturated amides (2a ～ d and 6) in the presence of trimethyl- chlorosilane, triethylamine and zinc chloride to give benzo- and indolo[a]- quinolizidines (5a ～ e and 7).     

ABSORPTION POLARIZATION PROPERTIES OF LIGHT-ADAPTED BACTERIORHODOPSIN IN THE 266–620nm REGION

Abstract— Using the method of polarized photochemistry, the polarization of the first daughter (K₆₁₀) in the photocycle of light-adapted bacteriorhodopsin (bR₅₇₀) is determined relative to the polarization of the photolysis pulse for different absorption regions of bR₅₇₀. The results are discussed in terms of recent spectroscopic assignments of bR₅₇₀, and in the 310–266 nm region, in terms of energy transfer processes between the apoprotein and the retinal.     

Efficient photocleavage of DNA utilising water-soluble lipid membrane-incorporated [60]fullerenes prepared using a [60]fullerene exchange method

Various types of lipid membrane-incorporated C60 with high C60 concentrations can be prepared easily in several hours using the C60 exchange method and the photocleaving activity of cationic lipid membrane-incorporated C60 was appreciably higher than that of the C60.gamma-CDx complex.     

Atomic and molecular absorption spectra of indium in air-acetylene flame

Absorption spectra of both atomic and molecular species in the air-acetylene flame, which are produced when the aqueous solutions of indium dissolved in HNO₃, HF, HCl, HBr and HI were aspirated into the flame, have been investigated in the u.v. region. Numerous atomic absorption lines of indium have been observed in the absorption spectra. Most of these lines were previously listed only as emission lines. Those atomic lines have been ascribed to the electronic transitions from the ground states of 5p ²P_1/2⁰ and 5p ²P_3/2⁰ to the excited states such as ls ²S_1/2, md ²D_3/2, nd ²D_5/2, 4p^{2 4}P_1/2, 4p^{2 4}P_3/2 and 4p^{2 4}P_5/2, respectively, where 13 l 6 and 14 m,n 5. The molecular absorption bands for InF, InCl and InBr in the airacetylene flame have been also observed near 234 nm, 267 nm and 282 nm, respectively, as the electronic transition of ¹Σ⁺ → ¹Π₁ Those absorption bands show fine structures due to the molecular vibrations. The spectral parameters for the molecular vibrations have been obtained from the simulations of the observed spectra. The molecular absorption band for InI was not observed because of the decomposition of the molecule in the flame. In addition, the molecular absorption band for InO has been observed near 273 nm and those for NO near 205 and 215 nm.     

Studies on the syntheses of heterocyclic compounds—DXXII : Photolytic synthesis of 1,12-dihydroxy-2,10,11- trimethoxyhomoaporphine

Photolysis of 1-(2-bromo-3-hydroxy-4,5-(dimethoxyphenethyl)-1,2,3,4-tetrahydro-7-hydroxy-6-methoxy-2-methylisoquinoline (8) gave 4,5,6,6a-tetrahydro-1,12-dihydroxy-2,10,11-trimethoxy-6-methylhomoaporphine (7), which is identical with the alkaloid CC-24 isolated from Cholchicum cornigerum.     

Studies on the syntheses of heterocyclic compounds. Part CDXCVII. Total syntheses of (±)-cryptaustoline and (±)-thaliporphine by the benzyne reaction

The indisputable benzyne reaction of 1-(5-bromo-3,4-dimethoxybenzyl)-1,2,3,4-tetrahydro-7-hydroxy-6-metlioxy-2-methylisoquinoline (II) with sodium amide in liquid ammonia afforded the following compounds, (±)-cryptaustoline iodide (VI), (±)-thaliporphine (VIII), 1 -(3,4-dimeth-oxybenzyl)- (III), and 1 -(2-amino-4,5-dimethoxybenzyl)-l,2,3,4-tetrahydro-7-hydroxy-6-meth-oxy-2-methylisoquinoline (IV).     

Simultaneous multi-element determination of trace metals in sea water by inductively-coupled plasma atomic emission spectrometry after coprecipitation with gallium

Coprecipitation with gallium hydroxide is studied for the preconcentration of trace metals in sea water before multi-element analysis by inductively-coupled plasma/atomic emission spectrometry. Gallium precipitates at pH 9 only when magnesium is present. Optimum conditions are established for multi-element preconcentration and removal of matrix elements. The method is almost free from contamination because of the use of highly pure gallium meetal and only a small amount of sodium hydroxide for pH adjustment. Spectral interferences from gallium are negligible and a concentratioin factor of more than 200 can be obtained. Detection limits range from a few ng l^?1 to 150 ng l^? for Al, Co, Cr, Fe, La, Mn, Ni, Ti, V, Zn, Y and Pb. Artificial and natural sea-water samples can be analyzed with adequate precision.     

Studies on the syntheses of heterocyclic compounds. Part CCCXV erythrinan and related compounds. II . An alternative synthesis of cis-16-hydroxy-15-methoxyerythrinan-8-one and its mass spectrum

Phenolic cyclization of 2-ethoxycarbonylmethylidenecyclohexanone (IV) with 3-hydroxy-4-methoxyphenethylamine (V) were performed in the process of finding a synthetic approach to dihydroerysolidine (I). Thus, 16-hydroxy-15-methoxyerythrinan-6-ene-8-one (VI) and 16-hydroxy-15-methoxyerythrinan-7-ene-8-one (VII) were synthesized, both of which were hydrogenated in the presence of Adams platinum to give the same product (XI). Furthermore, on the basis of the mass spectra of XI and XII, these compounds were assumed to be stereoisomeric at the C₅- and C₆-positions.