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11.
The synthesis of 1,2,4-triazolo[4,3-b]pyridazines and the unknown ring system, pyrazino[2,3-d]-1,2,4-triazolo[4,3-b]pyridazine, has been achieved. The preparation of the new tricyclic 1,2,4-triazole was accomplished first by ring closure of the triazole ring followed by formation of the pyrazine ring. Substitution of the pyrazino[2,3-d]-1,2,4-triazolo[4,3-b]pyridazine ring system was carried out in order to provide information of its reactivity and to provide a variety of interesting compounds for biological testing. 相似文献
12.
Jiann-Kuan Luo M. J. Musmar Raymond N. Castle 《Journal of heterocyclic chemistry》1991,28(5):1309-1313
Four substituted [1]benzothieno[2,3-c]quinolines 14a-14d were prepared by photocyclization of the appropriate carboxamides 8a-8d to the corresponding [1]benzothieno[2,3-c]quinolin-6(5H)-ones 12a-12d followed by chlorination to 6-chloro[1]benzothieno[2,3-c]quinolines 13a-13d and dechlorination resulting in the title compounds. Treatment of 14a-14d with iodomethane furnished the corresponding N-methyl quaternary salts 5a-5d . 相似文献
13.
Yoshinori Tominaga Milton L. Lee Raymond N. Castle 《Journal of heterocyclic chemistry》1981,18(5):977-979
The cyclization of 2-acetonylthionaphthalene, prepared from 2-mercaptonaphthalene (1) and chloro-acetone in the presence of sodium hydroxide, with polyphosphoric acid gave 1-methylnaphtho[2,1-b]thiophene (4) in 64% overall yield from 1. By bromination with N-bromosuccinimide, 4 was converted in 40% yield into l-bromomethylnaphtho[2,1-b]thiophene (8) . Treatment of 8 with potassium cyanide in a phase-transfer medium gave l-cyanomethylnaphtho[2,1-b]thiophene (10) in good yield. Compound 10 was reduced to the corresponding aldehyde 11 and then cyclized with polyphosphoric acid to phenaleno[l,9-bc]thiophene (12) in 24% overall yield from 10. 相似文献
14.
Marvin L. Tedjamulia Hirotaka Kudo Raymond N. Castle Milton L. Lee 《Journal of heterocyclic chemistry》1984,21(2):321-325
The syntheses of naphtho[1,2–6:7,6-b′]bisbenzo[b]thiophene ( 4 ), naphtho[1,2–6:7,8-b′]bisbenzo[b]thiophene ( 5 ), naphtho[2,1-b:7,6-b′]bisbenzo[b]thiophene ( 8 ), naphtho[2,1-b:7,8-b′]bisbenzo[b]thiophene ( 9 ), naphtho-[1,2–6:5,6-b′]bisbenzo[b]thiophene ( 14 ), naphtho[1,2–6:6,5-b]bisbenzo[b]thiophene ( 17 ) and naphtho[2,1–6:-6,5-b′]bisbenzo[b]thiophene ( 23 ) are reported. 相似文献
15.
The state-of-the-art of analysis for acrylamide in food is reviewed. The majority of analytical methods adopts a similar approach: addition of internal standard to the specimen, extraction with water, purification of extract using a solid-phase extraction cartridge, and then determination using either gas chromatography coupled to mass spectroscopy (GC/MS) after bromination, or direct measurement with liquid chromatography coupled to mass spectroscopy (LC/MS). The available methods generally show good agreement and are likely to be accurate. However, improvements in precision (within-laboratory) and repeatability (between-laboratory) are needed by particular data users. 相似文献
16.
Jiann-Kuan Luo Andrew S. Zektzer Raymond N. Castle 《Journal of heterocyclic chemistry》1991,28(3):737-743
The synthesis of two novel polycyclic heterocyclic ring systems via photocyclization are reported. These are benzo[f]thieno[2′,3′:4,5]thieno[2,3-c]quinoline and benzo[A]thieno-[2′,3′:4,5]thieno[2,3-c]quinoline. The total assignment of their 1H- and 13C-nmr spectra was determined by utilizing two-dimensional nmr spectroscopic methods. 相似文献
17.
A series of eight alkyl and aryl alpha-nitro ketones were prepared by the potassium dichromate oxidation of the corresponding nitro alcohols. Short reaction times allowed for the easy isolation of pure nitro ketones that are devoid of starting materials and/or other oxidation side products. 相似文献
18.
[Chemical reaction: See text] Lewis acid promoted radical conjugate additions to beta-substituted alpha,beta-unsaturated alpha-nitro esters and amides were investigated. With achiral Lewis acids, there was competition between the desired radical conjugate addition and undesired alkene reduction mediated by Bu3nH. Zinc Lewis acids provided the greatest amounts of addition products with both substrate classes. Studies with Bu3nD indicated that the acidic alpha-stereocenter of the alpha-nitro ester products does not racemize under controlled workup conditions. The corresponding alpha-nitro amides racemized significantly during chromatography, but this problem could be greatly minimized by subjecting the crude adducts to subsequent transformations. Indium-mediated reduction of the nitro group followed by acylation of the resulting amine provided good yields of beta-substituted alpha-amino acid derivatives with mimimal levels of racemization. Attempts to use chiral Lewis acids in a stereoselective variant of this process revealed that Kanemasa's DBFOX/Ph ligand (14a) was uniquely effective. Moderate to good ee's and low dr's were obtained with amide substrates. Determination of the absolute configurations of the syn and anti isomers of adduct 7b showed that the hydrogen atom abstraction step was significantly more stereoselective than the radical conjugate addition step. A model for substrate binding to the chiral Lewis acid is presented. 相似文献
19.
Nikola Toljic Kaz Adamiak G.S. Peter Castle Hong-Hsiang Kuo Hua-Tzu Fan 《Journal of Electrostatics》2012,70(6):499-504
In this paper, a full three dimensional FLUENT numerical model of the electrostatic coating process with the embedded moving mesh capability and piecewise linear type target motion is presented. The model includes target geometries that do not exhibit symmetry. All the dominant mechanical and electrical phenomena are taken into account. Mechanical phenomena include shaping air effects, downdraft effects and the motion of the polydispersed particles. Electrical phenomena include the particle space charge distribution, corona discharge and the electrohydrodynamic flow effects. It was demonstrated that the numerical model can accurately mimic the type of the motion used in real world applications. 相似文献
20.
When exposed to a corona discharge, a dielectric droplet spreads over a grounded substrate. In the present work, the spreading of dielectric liquids subjected to a short-term exposure is investigated. A simple theoretical model was developed to find the spreading law at the very beginning of exposure. The asymptotic approximation for the surface charge density and the interfacial pressure showed that the droplet spreading immediately after the exposure obeys t1/2 law. The high speed imaging of the spreading revealed the same trend as predicted by the theoretical model. 相似文献