25559-38-0Relevant academic research and scientific papers
Ability of the Putative Decomposition Products of 2,3-dioxetanes of Indoles to Photosensitize Cyclobutane Pyrimidine Dimer (CPD) Formation and its Implications for the “Dark” (Chemisensitized) Pathway to CPDs in Melanocytes?
Cacchillo, Elena M.,Niedzwiedzki, Dariusz M.,Taylor, John-Stephen,Wang, Yanjing
, (2021/10/14)
The formation of cyclobutane pyrimidine dimers (CPDs) by a “dark” pathway in melanocytes has been attributed to chemisensitization by dioxetanes produced from peroxynitrite oxidation of melanin or melanin precursors. These dioxetanes are proposed to decompose to triplet state compounds which sensitize CPD formation by triplet–triplet energy transfer. To determine whether such compounds are capable of sensitizing CPD formation, the putative decomposition products of 2,3-dioxetanes of variously substituted indoles were synthesized and their triplet state energies determined at 77?K. Their ability to photosensitize CPD formation was determined by an enzyme-coupled gel electrophoresis assay in comparison with norfloxacin (NFX) which has the lowest triplet energy known to sensitize CPD formation. The decomposition products of 2,3-dioxetanes of 5-hydroxy and 5,6-dimethoxy indoles used as models for melanin precursors had lower triplet energies and were incapable of photosensitizing CPD formation. Theoretical calculations suggest that the decomposition products of the 2,3-dioxetanes of melanin precursors DHI and DHICA will have similarly low triplet energies. Decomposition products of the 2,3-dioxetanes of indoles lacking oxygen substituents had higher triplet energies than NFX and were capable of photosensitizing CPD formation, suggesting that peroxynitrite oxidation of tryptophan could play a hitherto unrecognized role in the dark pathway to CPDs.
Silver-Catalyzed Three-Component Coupling Reaction of Amines, 2-Isocyanobenzaldehydes, and 2,2,2-Trifluorodiazoethane and Synthesis of Trifluoromethyl-Substituted Indolo[1,2-c]quinazolines
Meng, Xiang-He,Peng, Ju-Yin,Yang, Ming,Zhao, Yu-Long
, p. 244 - 250 (2020/12/01)
A silver-catalyzed three-component coupling reaction of amines, 2-isocyanobenzaldehydes, and 2,2,2-trifluorodiazoethane has been developed. This reaction provides an efficient method for the construction of CF3-containing dihydroquinazolines. On the basis of this reaction, using trifluorodiazoethyl-substituted dihydroquinazolines as synthons, trifluoromethyl-substituted indolo[1,2-c]quinazolines were prepared in high yields via a TBHP/KI-mediated sequential intramolecular cyclization and aromatization process. (Figure presented.).
PPTS-Catalyzed Bicyclization Reaction of 2-Isocyanobenzaldehydes with Various Amines: Synthesis of Diverse Fused Quinazolines
Meng, Xiang-He,Wu, Dan-Ni,Zhang, Yu-Jia,Zhao, Yu-Long
, p. 1923 - 1929 (2021/02/26)
A PPTS (pyridinium p-toluenesulfonate)-catalyzed bicyclization reaction of 2-isocyanobenzaldehydes as 1,5-dielectrophiles with various amines has been developed. The reaction not only provides a simple and efficient strategy for the assembly of structurally diverse fused quinazoline derivatives from readily available substrates under metal-free and mild conditions in a single step with only water and hydrogen as the by-products, but also opens the way to the application of o-formyl arylisocyanides in the synthesis of nitrogen-containing heterocycles. (Figure presented.).
Peroxygenase and oxidase activities of dehaloperoxidase-hemoglobin from Amphitrite ornata
Barrios, David A.,D'Antonio, Jennifer,McCombs, Nikolette L.,Zhao, Jing,Franzen, Stefan,Schmidt, Andreas C.,Sombers, Leslie A.,Ghiladi, Reza A.
supporting information, p. 7914 - 7925 (2014/06/23)
The marine globin dehaloperoxidase-hemoglobin (DHP) from Amphitrite ornata was found to catalyze the H2O2-dependent oxidation of monohaloindoles, a previously unknown class of substrate for DHP. Using 5-Br-indole as a representative substrate, the major monooxygenated products were found to be 5-Br-2-oxindole and 5-Br-3-oxindolenine. Isotope labeling studies confirmed that the oxygen atom incorporated was derived exclusively from H2O2, indicative of a previously unreported peroxygenase activity for DHP. Peroxygenase activity could be initiated from either the ferric or oxyferrous states with equivalent substrate conversion and product distribution. It was found that 5-Br-3-oxindole, a precursor of the product 5-Br-3-oxindolenine, readily reduced the ferric enzyme to the oxyferrous state, demonstrating an unusual product-driven reduction of the enzyme. As such, DHP returns to the globin-active oxyferrous form after peroxygenase activity ceases. Reactivity with 5-Br-3-oxindole in the absence of H2O2 also yielded 5,5′-Br2-indigo above the expected reaction stoichiometry under aerobic conditions, and O2-concentration studies demonstrated dioxygen consumption. Nonenzymatic and anaerobic controls both confirmed the requirements for DHP and molecular oxygen in the catalytic generation of 5,5′-Br2-indigo, and together suggest a newly identified oxidase activity for DHP.
ortho-Lithiophenyl isocyanide: A versatile precursor for 3H-quinazolin-4-ones and 3H-quinazolin-4-thiones
Lygin, Alexander V.,De Meijere, Armin
supporting information; experimental part, p. 389 - 392 (2009/09/05)
(Chemical Equation Presented) ortho-Lithiophenyl isocyanide has been generated from ortho-bromophenyl isocyanide and successfully employed toward the synthesis of 2-substituted phenyl Isocyanides as well as 2,3-disubstituted 3H-quinazoline-4-ones and 3H-q
Reactions of ortho-lithiophenyl (-hetaryl) isocyanides with carbonyl compounds: Rearrangements of 2-metalated 4H-3,1-benzoxazines
Lygin, Alexander V.,De Meijere, Armin
supporting information; experimental part, p. 4554 - 4559 (2009/09/30)
(Chemical Equation Presented) ortho-Lithiophenyl (-hetaryl) isocyanides react with aldehydes and ketones providing isocyanoalcohols 8 (36-89%, nine examples), 4H-3,1-benzoxazines 9 (45-78%, six examples) or, after two types of rearrangements, isobenzofura
Investigation on the photoreactions of nitrate and nitrite ions with selected azaarenes in water
Beitz, Toralf,Bechmann, Wolfgang,Mitzner, Rolf
, p. 351 - 361 (2007/10/03)
The photoreactions of selected azaarenes with nitrate and nitrite ions were investigated under irradiation at λ = 313 nm. The excitation of both anions leads to several photochemical reactions forming mainly hydroxyl radicals and nitrogen oxides. The purification capability of natural waters i.e. the oxidation of inorganic and organic substances results from the formation of hydroxyl radicals. Nitrated isomers of azaarenes were found among the main products of the investigated photoreactions. The nitrogen oxides were responsible for the production of nitrated derivatives which possess a high toxic potential. Their formation was explained by the parallel occurance of two mechanism, a molecular and a radical one. The molecular mechanism became more important with increasing ionisation potentials of the azaarenes. The spectrum of oxidized products corresponded to the one got in the photoreactions of azaarenes with hydrogen peroxide. The formation of several oxidation and nitration products of the pyridine ring with its low electron density was explained by the reaction of excited states of azaarenes. The photoreactions with nitrite ions only led to the formation of oxidized and nitrated products. Nitroso products were not formed. The reactivity of nitrogen monoxide is too low for its reaction with the azaarenes.
One-Step Conversion of Aryl Nitro Compounds to N-Monosubstituted Formamides
Hrvatin, Paul,Sykes, Andrew G.
, p. 1069 - 1070 (2007/10/03)
A concise general route to N-monosubstituted formamides starting from aryl nitro compounds substituted with H, Cl, OMe, CHO, and NHCHO is described.
Ring Fission of Quinazolines by Means of the Reissert Reaction
Higashino, Takeo,Kokubo, Hiroyasu,Goto, Ayako,Takemoto, Masumi,Hayashi, Eisaku
, p. 3690 - 3694 (2007/10/02)
Under the Reissert reaction conditions, quinazoline (1a) afforded 2'-formylbenzanilide (2a), o-aminobenzaldehyde (3a), and N-formylbenzamide (4).Similarly, 4-methyl- (1b) and 4-ethoxyquinazoline (1c) gave the corresponding benzanilides 2b and 2c, respectively, o-aminoacetophenone (3b, from 1b), and benzamide (5).It was confirmed that the same results were obtained in the absence of the cyanide ion.A substituent at the 2-position prevented the ring fission, and only the corresponding N3-benzoyl pseudo-base (14) was obtained.The generality of the ring fission was shown by the reactions of 1-phenyl-1H-pyrazolopyrimidine (6) and 3-phenyl-3H-1,2,3-triazolopyrimidine (8), giving 5-amino-1-phenyl-1H-pyrazole-4-carbaldehyde (7) and 5-amino-1-phenyl-1H-1,2,3-triazole-4-carbaldehyde (9), respectively.Keywords - 4-substituted quinazoline; 1H-pyrazolopyrimidine; 3H-1,2,3-triazolopyrimidine; 2'-acylbenzanilide; 2-aminophenyl alkyl ketone; N-formylbenzamide; ring fission.
