- N -Chlorinative Ring Contraction of 1,4-Dimethoxyphthalazines via a Bicyclization/Ring-Opening Mechanism
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An unprecedented N -chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n -Bu 4NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O -silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA.
- Im, Jeong Kyun,Jeong, Ilju,Yang, Byeongdo,Moon, Hyeon,Choi, Jun-Ho,Chung, Won-Jin
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p. 1760 - 1770
(2020/12/30)
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- N-Chlorination-induced, oxidative ring contraction of 1,4-dimethoxyphthalazines
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A rarely explored oxidative ring contraction of electron-rich 1,2-diazine is described. Upon treatment with an electrophilic chlorinating reagent (TCICA), 1,4-dimethoxyphthalazines undergo an N-chlorination-induced ring contraction that is accompanied by the loss of one nitrogen atom. The scope of this unusual reactivity was examined with a range of 1,4-dimethoxyphthalazine derivatives. In addition, a mechanism proceeding via a bicyclic species was proposed on the basis of an isolated reaction intermediate and DFT calculations.
- Im, Jeong Kyun,Yang, ByeongDo,Jeong, Ilju,Choi, Jun-Ho,Chung, Won-jin
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supporting information
(2020/06/03)
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- Design, synthesis, and insecticidal activities of phthalamides containing a hydrazone substructure
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Fluobendiamide is the first commercialized artificial synthetic insecticide acting on the ryanodine receptor. This new molecule possesses a combination of excellent insecticidal activity and eco-friendly characteristics with a skeleton structure of phthalamide. In this study, we incorporated hydrazone, present in many pesticidal compounds reported during the last two decades, into phthalamide derivatives via Schiff-base condensation and aminolysis to obtain 21 new compounds; these compounds were characterized by proton nuclear magnetic resonance (1H NMR), infrared spectroscopy (IR), and high-resolution mass spectrometry (HRMS) or elemental analysis. A preliminary bioassay against peach aphids (Myzus persicae) revealed that the title compounds exhibited good stomach toxicity at 600 mg/L. Twelve new compounds were found to display higher activity than postive control flubendiamide (LC50 = 184.099 mg/L), however, LC50 was less than 100 mg/L only for compounds 4e, 4o, 4s, 4t (59-77 mg/L). That is, combinations of a p-fluorophenyl or (methyl)thienyl group at the Ar position with an isopropyl or cyclohexyl group at the R position might improve the lethality of the designed phthalamide derivative. Preliminary results of a bioassay at 600 mg/L against diamondback moth (Plutella xylostella, Linnaeus) showed that only the title compound 4e possessed good larvicidal activity. On comparison of the bioassay results of stomach toxicity and larvicidal activity, it is noteworthy that the compound incorporating phenylpyrazolyl exhibited good larvicidal activity and poor stomach activity.
- Liu, Ming,Wang, Yi,Wangyang, Wei-Zi,Liu, Feng,Cui, Yong-Liang,Duan, You-Sheng,Wang, Min,Liu, Shang-Zhong,Rui, Chang-Hui
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body text
p. 6858 - 6863
(2011/08/06)
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- ORGANIC COMPOUNDS AND THEIR USES
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The present disclosure relates to compounds relating to the diagnosis and treatment of pathologies relating to the Hedgehog pathway, including but not limited to tumor formation, cancer, neoplasia, and non-malignant hyperproliferative disorders; specifically relating to compounds of formula (I).
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Page/Page column 76
(2008/12/07)
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- 4-Benzylamino-1-chloro-6-substituted phthalazines: Synthesis and inhibitory activity toward phosphodiesterase 5
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We synthesized various 4-benzylamino-1-chloro-6-substituted phthalazines (15) and 4-benzylamino-1-chloro-7-substituted phthalazines (16) and evaluated their inhibitory activity toward phosphodiesterase 5 (PDE5) purified from porcine platelets. The PDE5-inhibitory activities of 15 were greater than those of the isomers (16). The preferred substituent at the 4-position of phthalazine was a (3-chloro-4-methoxybenzyl)amino group, and those at the 6- position were cyano, nitro, and trifluoromethyl groups. Compounds 15a (IC50 = 4.8 nM), 15f (3.5 nM), and 15i (5.3 nM) were more potent inhibitors than E4021 (8.6 nM). Compounds 15a and 15f also showed vasorelaxant activity in isolated porcine coronary arteries precontracted with prostaglandin F(2α) (10-5 M). The EC50 values for vasorelaxant action of 15a, 15f, and E4021 were 150, 160, and 980 nM, respectively. These results show that novel PDE5 inhibitors possessing a potent vasorelaxant effect may exist among phthalazine derivatives.
- Watanabe, Nobuhisa,Kabasawa, Yasuhiro,Takase, Yasutaka,Matsukura, Masayuki,Miyazaki, Kazuki,Ishihara, Hiroki,Kodama, Kohtarou,Adachi, Hideyuki
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p. 3367 - 3372
(2007/10/03)
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- Implementation of a combinatorial cleavage and deprotection scheme. 1. Synthesis of phthalhydrazide libraries
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Phthalhydrazide libraries are synthesized in solution from substituted hydrazines and phthalimides in several different library formats including single compounds, indexed sub-libraries and a full library. When carried out during solid-phase synthesis, this combinatorial cleavage and deprotection scheme offers the possibility for generating a diverse library of substituted phthalhydrazides. Copyright
- Nielsen, John,Rasmussen, Palle H.
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p. 3351 - 3354
(2007/10/03)
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- Benzocyclobutenes. Part 4. Synthesis of Benzocyclobutene-1,2-diones by Pyrolytic Methods
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Oxidation of the cyclic hydrazides prepared from phthalic anhydrides in the presence of anthracene gives the corresponding Diels-Alder adducts which, on flash vacuum pyrolysis, give benzocyclobutene-1,2-dione (BBD) and its 4-chloro, 3,6- and 4,5-dichloro, 4,5-dibromo, and 4,5-dimethyl derivatives in 75-98percent yield.Cyclobuta- and cyclobuta-naphthalene-1,2-dione as well as cyclobuta- and cyclobuta-pyridine-1,2-dione have been prepared similarly; the last three of these diones are very unstable.Cyclobutanaphthalene-1,2-dione has also been made by pyrolysis of benzindene-1,2,3-trione.Attempts to make thiophen and furan analogues of BBD from appropriate anthracene adducts failed as did attempts to make tetrachloro- and tetrabromo-derivatives of BBD by the pyrolysis of tetrahalogenophthalimidosulphoximides.
- Gould, Ken J.,Hacker, Nigel P.,McOmie, John F. W.,Perry, David H.
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p. 1834 - 1840
(2007/10/02)
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