- Photoinduced transition-metal- And external-photosensitizer-free intramolecular aryl rearrangementviaC(Ar)-O bond cleavage
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The use of photochemical reactions that do not require expensive photocatalysts or transition metals is an environmentally friendly strategy for accomplishing a variety of structural transformations. Herein, we report a protocol for photoinduced transition-metal- and external-photocatalyst-free intramolecular heteroaryl/aryl rearrangement reactions of 2-heteroaryl/aryloxybenzaldehydes. The protocol was compatible with a variety of functionalities, including methyl, methoxy, cyano, ester, trifluoromethyl, halogen, and heteroaromatic rings. Control experiments suggested that the reaction proceededviaa photoinduced intramolecular heteroaryl/aryl rearrangement process involving photoexcitation of the aldehyde carbonyl group, radical addition, C-C bond formation and C(Ar)-O bond cleavage.
- Dou, Qian,Li, Chao-Jun,Zeng, Huiying
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p. 5740 - 5744
(2020/06/26)
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- Synthesis method of 2-(2-amino-5-bromobenzoyl) pyridine
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The invention discloses a synthesis method of 2-(2-amino-5-bromobenzoyl)pyridine. The method comprises the following processing steps: S1, reacting 4-bromo-2-bromomethylphenol, used as an initial rawmaterial, with MEMCl in an aprotic solvent to obtain 4-bromo-2-(bromomethyl)-1-((2-methoxyethoxy)methoxy)benzene; S2, reacting the 4-bromo-2-(bromomethyl)-1-((2-methoxyethoxy)methoxy)benzene with trimethyl borate under the action of a catalyst to prepare a boric acid compound (5-bromo-2-(((2-methoxyethoxy)methoxy)benzyl) boric acid; and S3, adding 2-bromopyridine and [1,1'-bis(diphenylphosphino)ferrocene]-palladium dichloride into the (5-bromo-2-(((2-methoxyethoxy)methoxy)benzyl)boric acid in order to prepare 2-(5-bromo-2-(((2-methoxyethoxy)methoxy)benzyl)pyridine. The method has the advantages of high atom utilization rate, environmental friendliness due to the recoverable solvent, high yield, convenience in operation, and suitableness for industrial production.
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Paragraph 0020; 0024; 0027; 0031; 0034; 0038
(2020/02/19)
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- Pyridine derivatives, their production and use
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Pyridine derivatives of the formula STR1 wherein the ring A stands for an optionally further substituted benzene ring; the ring B stands for an optionally substituted pyridine ring; Q stands for hydroxyl group, or OQ 1 or Q 1 wherein Q 1 stands for an optionally substituted aliphatic hydrocarbon group; and n denotes 0 or 1, or their salts, which have potassium.channel opening activity and are useful as therapeutic agents of circulatory diseases such as angina pectoris, hypertension, etc.
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- Synthesis and biological activity of novel 1,3-benzoxazine derivatives as K+ channel openers
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A new series of 1,3-benzoxazine derivatives with a 2-pyridine 1-oxide group at C4 was designed to explore novel K+ channel openers. Synthesis was carried out by using a palladium(0)-catalyzed carbon-carbon bond formation reaction of imino-triflates with organozinc reagents and via a new one-pot 1,3-benzoxazine skeleton formation reaction of benzoylpyridines. The compounds were tested for vasorelaxant activity in tetraethylammonium chloride (TEA) and BaCl2-induced and high KCl-induced contraction of rat aorta to identify potential K+ channel openers, and also for oral hypotensive effects in spontaneously hypertensive rats. An electron- withdrawing group with the proper shape at C6 and a methyl or halogens group at C7 of the 1,3-benzoxazine nucleus were required for the development of optimal vasorelaxant and hypotensive activity. In particular, 2-(6-bromo-7- chloro-2,2-dimethyl-2H-1,3-benzoxazin-4-yl)pyridine 1-oxide (71) showed more potent vasorelaxant activity (EC50=0.14 μM) against TEA and BaCL2- induced contraction and longer-lasting hypotensive effects than cromakalim (1).
- Yamamoto, Satoshi,Hashiguchi, Shohei,Miki, Shokyo,Igata, Yumiko,Watanabe, Toshifumi,Shiraishi, Mitsuru
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p. 734 - 745
(2007/10/03)
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