Oxidation of 7,8‐diaminotheophylline (1) with lead tetraacetate in refluxing toluene gave a mixture of 3‐amino‐5,7‐dimethylpyrimido[4,5‐e][1,2,4]triazine‐6,8‐dione ( 2 ) and 6‐cyanoimino‐5‐diazo‐1,3‐dimethylpyrimidine‐2,4‐dione ( 4 ). The latter was transformed to 2 by the reaction with 1‐propanethiol in quantitative yield. The reaction of 4 with methanol, ethanol and 1‐propanol in the presence of rhodium ( II ) acetate gave 5‐alkoxy‐6‐(2‐alkyl‐3‐isoureido)‐1,3‐dimethylpyrimidine‐2,4‐diones ( 7a‐c ). A similar reaction of 4 with alkylamines such as n‐propylamine, n‐butylamine, isobutylamine and n‐hexylamine gave a mixture of 7‐alkyl‐8‐aminotheophyllines ( 8a‐d ) and (5‐alkylamino‐1,3‐dimethyl‐2,4‐dioxopyrimidin‐6‐yl)cyanamides ( 9a‐d ). 相似文献
Spores of Bacillus subtilis, containing plasmid (B. subtilis BD 366(pUB110, Trp C2 thr 5)), were prepared free of additives and the effect of water on their radiation sensitivity under aerobic condition was investigated. The moisture content of spores was controlled by (i) drying over CaCl2 (Aw = 0.0), (ii) equilibrating with the vapor of saturated aqueous NaCl solution (Aw = 0.7), or (iii) suspending in water (Aw = 1.0). The resistance of spores to radiation increased with increasing moisture content. The analysis of spore DNA by agarose gel electrophoresis showed that DNA damage (strand breaks) decreased with increasing water activity of the spores, a finding concomitant with the observed survival rates. 相似文献
Summary: The cationic ring‐opening copolymerization behavior of SOC1 with BOXT and the properties of the obtained cross‐linked copolymers are described. SOC1 and BOXT are cationically copolymerized under various feed ratios to obtain the corresponding cross‐linked copolymers in 73–96% yields. The volume change during copolymerization could be controlled by the addition of SOC1 to obtain non‐shrinking or volume‐expanding copolymers. The glass transition temperatures (Tg) of the copolymers also decrease linearly with the feed ratio of SOC1, which suggests that the introduction of the flexible poly(SOC1) segment into the rigid BOXT cross‐linked segment relieves the internal stress in the resins that severely degrade their mechanical properties.
Organic electroluminescent devices were fabricated using a poly(arylene ether sulfone)-containing tetraphenylbenzidine (PTPDES) and tris(8-quinolinolato)-aluminum(III) complex, Alq, as the hole transport layer and the electron-transporting emitter layer, respectively. A device structure of glass substrate/indium—tin oxide (ITO)/PTPDES/Alq/Mg : Ag was employed. Hole injection from ITO through the PTPDES layer to the Alq layer and concomitant electroluminescence from the Alq layer were observed. Bright green light with a luminance of 14,000 cd/m2 was observed at a drive voltage of 14 V, indicating that the polymer possesses a high hole mobility and a high electron-blocking capability. 相似文献
The spontaneous unimolecular dissociation reaction of methyl lactate (1) ionized by electron impact was investigated by a combination of mass-analyzed ion kinetic energy spectrometry and deuterium labeling. The metastable ions 1+· decompose in a variety of ways: four fragment peaks are observed at m/z 89, 76, 61, and 45, which correspond to the losses of ?H3, CO, CH3?O, and ?OOCH3, respectively. Double hydrogen atom transfer occurs in the third reaction. The source-generated m/z 61 ions decompose into oxygen-protonated methanols at m/z 33 ([CH3OH2+]) by the loss of CO with double hydrogen atom migration. Both hydroxyl and methyne hydrogen atoms in 1 +· are present in the resultant protonated methanols. 相似文献
1,2,3,4-Tetrahydroquinolines should be applicable to the development of new pharmaceutical agents. A facile synthesis of 1,2,3,4-tetrahydroquinolines that is achieved by a photoinduced formal [4+2] cycloaddition reaction of acyclic α,β-unsaturated amides and imides with N,N-dialkylanilines under visible-light irradiation, in which a new IrIII complex photosensitizer, a thiourea, and an oxidant act cooperatively in promoting the reaction, is reported. The photoreaction enables the synthesis of a wide variety of 1,2,3,4-tetrahydroquinolines, while controlling the trans/cis diastereoselectivity (>99:1) and constructing contiguous stereogenic centers. A chemoselective cleavage of an acyclic imide auxiliary is demonstrated. 相似文献
The magnetic properties of intermetallic compounds RMn6Sn6 (T=Gd and Y) have been investigated by119Sn Mössbauer effect measurements. The differences of the hyperfine field on both the Sn1 and Sn3 sites were small between GdMn6Sn6 and YMn6Sn6, while the Mn sublattice orders ferromagnetically for R=Gd and antiferromagnetically for R=Y. This result indicated that Mn moments order antiferromagnetically in the intra-plane of the Kagomè net in YMn6Sn6. 相似文献