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1.
Said M. Bayomi 《中国化学会会志》1992,39(1):101-104
A convenient route is reported for the synthesis of fused pyrrolo[2,3-d][1,3]oxazine and pyrrolo[2,3-d]-pyrimidine derivatives from 2-amino-1-benzyl-3-t-butoxycarbonyl]-4,5-dimethylpyrrole. 相似文献
2.
Mounir A. I. Salem Wafaa M. Abdou Tarik E. Ali Azza A. Kamal Reham F. Barghash 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1007-1016
Abstract Fragmentation pathways of 14 organophosphorus compounds derived from diethyl spiro[pyrimidino[5,3][1,2]oxazole] phosphonates, diethyl (oxazolo[5,4-d]pyrimidine-4,6-dione)phosphonates, and diethyl (pyrimidino[4,5-b][1,4] oxazine)phosphonates were investigated by electron impact mass spectrometry (EI-MS). The intensity of the recorded molecular ion peaks showed various values depending on the nature of the compounds. Characteristic fragment ions were formed by successive loss of simple functional groups followed by decomposition of heterocycles connected to pyrimidine rings. 相似文献
3.
Transient spectroscopic characterization of the ring‐opening reaction of tetrahydrochromeno[2,3‐dimethyl]indole
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Ariel S. Marshall Robert A. Rogers Joseph W. Perry W. J. Brittain 《Journal of Physical Organic Chemistry》2016,29(5):221-226
Tetrahydrochromeno is a structural variant of spiropyran that undergoes a reversible ring‐opening to generate a colored nitrophenolate intermediate. Earlier work confirmed this intermediate through trimethylsilyl cyanide trapping under continuous irradiation. We have performed transient absorption spectroscopy to further characterize the mechanism of the ring‐opening reaction. Excitation at 355 nm produced a transient species with an absorption maximum at 445 nm, which we assign to the nitrophenolate unit of the ring‐opened product. The transient absorption decays after ~970 ns with small optical density changes corresponding to a 0.15 quantum yield. Exposure to oxygen did not exhibit a significant deleterious effect on the photoisomerization of the chromeno dye. Time‐dependent density functional theory corroborated spectroscopic assignments of the starting chromeno and the putative ring‐opened intermediate. The excited state behavior of this system parallels the structurally similar oxazine system reported by Raymo and coworkers. The one significant difference is the longer lifetime of the photochemically generated intermediate from chromeno. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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5.
S. V. Shishkina S. M. Desenko K. G. Nazarenko O. V. Shishkin 《Journal of Structural Chemistry》2005,46(1):191-194
X-ray diffraction investigation showed that protonation of 4H-benzo-[1,4]-oxazin-3-ylidene-cyclohexylamine occurs at the exocyclic nitrogen atom. In crystal, the cation has a structure with a distinct exocyclic C=N bond. 相似文献
6.
An efficient procedure for synthesizing oxazines was developed by the palladium(0)-catalyzed intramolecular cyclization of a benzamide through a π-allylpalladium (II) complex. Interestingly, the diastereoselectivity of oxazine ring formation was dominantly controlled by the bulkiness of various protecting groups on the secondary alcohols. 相似文献
7.
《Green Chemistry Letters and Reviews》2013,6(3):213-216
Abstract A simple, efficient, and practical procedure for the synthesis of various substituted 2,3-dihydro-2-phenyl-1H-naphtho[1,2-e][1,3]oxazines and 3,4-dihydro-3-phenyl-2H-naphtho[2,1-e][1,3]oxazines using KAl(SO4)2 12H2O (alum) as a non-toxic, reusable, inexpensive, and easily available catalyst is described using water as a solvent. These improved reaction conditions allow the preparation of a wide variety of substituted [1,3]oxazines in high yields and purity under mild reaction conditions. 相似文献
8.
The novel spirooxindoline fused [1,3]oxazines were efficiently synthesized from Diels‐Alder reaction of N‐arylmaleimides with 1,2‐dihydro‐2‐oxospiro[3H‐indole‐3,2′‐[2H,9aH‐pyrido[2,1‐b][1,3]oxazines], which were generated in situ from three‐component reactions of substituted pyridines and isatins with methyl propiolate, or dimethyl acetylenedicarboxylate. The stereochemistry of the products was clearly clarified by the analysis of 1H NMR data and single crystal structures of the obtained polycyclic compounds. 相似文献
9.
We synthesized boron containing 2-(4-methoxybenzyl)-4-(4-(4,4,5,5-tetramethyl-1,3,2-dioaborolan-2-yl)phenyl) phthalazin-1(2H)-one 3 and 7-methyl-3-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-2H-benzo[b][1,4] oxazine 8. The reaction of compound 2 with B2pin2 using potassium acetate as the base and Pd(PPh3)2Cl2 as the catalyst, produced the corresponding boron-containing derivative 3 as a white solid in 65% yield. Alternatively, we have synthesized compound 8 as a yellow solid in 59% yield using the Miyaura borylation reaction. The potassium trifluoro(4-(-methyl-2H-benzo[b][1,4]oxazine-3-yl)phenylborate 9 was then obtained after treatment of 8 with aqueous solution of KF2H in methanol as white solid product in 60% yield. The biological activities of the synthetic compounds are currently being evaluated. 相似文献
10.
A Multi‐Stimuli‐Responsive Oxazine Molecular Switch: A Strategy for the Design of Electrochromic Materials
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Xiaojun Wang Chang Gu Hongzhi Zheng Dr. Yu‐Mo Zhang Prof. Sean Xiao‐An Zhang 《化学:亚洲杂志》2018,13(9):1206-1212
A multi‐state and multi‐stimuli‐responsive oxazine molecular switch that combines an electro‐base property and sensitive base/acid‐responsive properties was designed and synthesized. The multi‐state structures of the molecular switch, with different colors, were predicted by comparing the optical properties with reference molecules and confirmed by using NMR spectroscopy. The color‐switching mechanism under stimulation with acids and bases was investigated by using DFT calculations. Three single states can be obtained and the switching is unidirectional under acid and base stimulation. The electrochromic phenomenon of the molecular switch, which combines its electro‐base and base‐sensitive properties, was demonstrated. An electrochromic device that exhibited good electrochromic properties with excellent reversibility (2000 cycles) and high coloration efficiency (804 cm2 C?1) was successfully constructed. 相似文献