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11.
A study was made of the use of calcium oxide as a catalyst at a temperature of 400–700° for the dehy-drocyclization of four primary arylamines: 2-aminobiphenyl, 1-aminotriphenylene (5c) , 2-phenoxyaniline, and N-(2-aminophenyl)pyrrole. Maximal yields of cyclized products isolated were 53% (carbazole), 52% (4H-naphtho[1,4-def]carbazole), 18% (phenoxazine), and 0%, respectively. Comparison is made with reported cyclizations of the corresponding nitro and azido starting materials. In one case, treatment of I-nitrotriphenylene with triethyl phosphite produced mainly diethyl N-(1-triphenylenyl)phosphoramidate (51%). Mono- and hemihydrochlorides of 5c are described. A mechanism for the catalyzed dehydrocy-clization is proposed. 相似文献
12.
Takaaki Nomura 《Annals of Global Analysis and Geometry》1994,12(1):237-260
We study the set of rankp idempotents in a topologically simple Hilbert Jordan algebra (JH-algebra for short). To produce the differential geometric structure on, we establish Jordan algebraic results concerning the structure of some two-generator subalgebras. We identify geodesics, the Riemannian distance and the sectional curvature of by using the Jordan algebraic structure. 相似文献
13.
Merrilactone A (1) has been shown to possess neurotrophic activity and thus is expected to hold therapeutic potential in the treatment of neurodegeneration diseases. In this paper, we report the total synthesis of (+/-)-1, employing, as key steps, a novel desymmetrization protocol of meso-diketone to construct the core cis-bicyclo[3.3.0]octyl system of 1 (3 --> 2) and a radical cyclization to install the highly congested C9-quaternary carbon (16 --> 17). 相似文献
14.
The ratio of N4+ to N3+ formed in the radiolysis of gaseous nitrogen has been measured to be 4.7 ± 0.4 using a time-resolved atmospheric pressure ionization mass spectrometer. The limit of error has been evaluated from the ion mass discrimination of the apparatus. 相似文献
15.
Takaaki Horaguchi Takako Oyanagi Evelyn Cuevas Creencia Kiyoshi Tanemura Tsuneo Suzuki 《Journal of heterocyclic chemistry》2004,41(1):1-6
A variety of nitrogen‐containing heterocycles were synthesized by passing vapors of aromatic amines over calcium oxide at 450–650 °C under nitrogen carrier gas. Reaction of 2‐aminobiphenyl 3a at 560 °C gave carbazole 4 in 80% yield. Reaction of 2, 2′‐diaminobiphenyl 3b afforded a mixture of carbazole 4 and 4‐aminocarbozole 6b. In the case of 2‐amino‐2′‐nitrobiphenyl 3c, benzo[c]cinnoline 7 was obtained along with carbazole 4. Reaction of 2‐amino‐2′‐methoxybiphenyl 3d gave four products of carbazole 4,4‐hydroxycarbazole 6e, phenanthridine 8 and dibenzofuran 9. Reaction of 2‐aminodiphenylmethane 5a afforded acridine 10. In the case of 2‐aminobenzophenone 5b, acridone 11 was obtained as a major product. Reaction of 2‐aminobenzhydrol 5c gave acridine 10. When 2‐aminodiphenylamine 5d was reacted, phenazine 12 was obtained in good yield. In contrast, reaction of 2‐aminodiphenyl ether 5e produced only 2‐hydroxydiphenylamine 13. Reaction of 4‐aminophenanthrene 14 produced 4H‐benzo[def]carbazole 15 in 61% yield. 相似文献
16.
Nakanishi I Miyazaki K Shimada T Iizuka Y Inami K Mochizuki M Urano S Okuda H Ozawa T Fukuzumi S Ikota N Fukuhara K 《Organic & biomolecular chemistry》2003,1(22):4085-4088
Electron-transfer reduction of molecular oxygen (O2) by the phenolate anion (1-) of a vitamin E model, 2,2,5,7,8-pentamethylchroman-6-ol (1H), occurred to produce superoxide anion, which could be directly detected by a low-temperature EPR measurement. The rate of electron transfer from 1- to O2 was relatively slow, since this process is energetically unfavourable. The one-electron oxidation potential of 1- determined by cyclic voltammetric measurements is sufficiently negative to reduce 2,2-bis(4-tert-octylphenyl)-1-picrylhydrazyl radical (DOPPH*) to the corresponding one-electron reduced anion, DOPPH-, suggesting that 1- can also act as an efficient radical scavenger. 相似文献
17.
Dialkoxydichlorosilanes ((RO)2SiCl2, R = alkyl) react almost completely with interlayer silanol groups in a layered silicate octosilicate to create a new crystalline silicate structure consisting of new five-membered rings arranged regularly on both sides of the silicate layers. The introduction of dialkoxysilyl groups to the interlamellar region of layered silicates with regular reaction sites provides a new methodology for the design and construction of novel crystalline silicate frameworks by a soft chemical route. 相似文献
18.
On-line sample preconcentration by a dynamic pH junction in conjunction with multiplexed capillary electrophoresis (CE) and UV detection represents a sensitive and high-throughput format for future metabolomic research, such as purine analysis. The optimization of purine focusing can be rapidly assessed by systematically altering the sample matrix properties, such as the buffer co-ion, pH and ionic strength using a 96-capillary array format. This method permits focusing of large sample injection volumes, resulting in over a 50-fold improvement in the concentration sensitivity. The limit of detection (S/N = 3) for purine metabolites was less than 8.0 x 10(-8) M under optimum conditions when using UV absorbance. Dynamic pH junction multiplexed CE demonstrated excellent linearity over a hundred-fold concentration range, as well as low inter-capillary precision in terms of normalized migration times and peak areas. The potential for clinically relevant high-throughput analyses of micromolar amounts of purine metabolites in urine was also demonstrated. 相似文献
19.
Zhenya Zhang Taisheng Quan Pomin Li Yansheng Zhang Norio Sugiura Takaaki Maekawa 《Applied biochemistry and biotechnology》2004,115(1-3):1033-1039
We studied biogas fermentation from alcohol waste fluid to evaluate the anaerobic digestion process and the production of
vitamin B12 as a byproduct. Anaerobic digestion using acclimated methanogens was performed using the continuously stirred tank reactor
(CSTR) and fixed-bed reactor packed with rock wool as carrier material at 55°C. We also studied the effects of metal ions
added to the culture broth on methane and vitamin B12 formation. Vitamin B12 production was 2.92 mg/L in the broth of the fixed-bed reactor, twice that of the CSTR. The optimum concentrations of trace
metal ions added to the culture liquid for methane and vitamin B12 production were 1.0 and 8 mL/L for the CSTR and fixed-bed reactor, respectively. Furthermore, an effective method for extracting
and purifying vitamin B12 from digested fluid was developed. 相似文献