3430-10-2Relevant articles and documents
Reduction of 2-amino-3- and -5-nitropyridine derivatives with hydrazine hydrate
Smolyar,Yutilov
, p. 115 - 118 (2009)
The reactions of 2-amino-3-nitropyridine and 2-amino-5-nitropyridine with hydrazine hydrate resulted in elimination of the amino group and reduction of the nitro group with formation of 3-aminopyridine. A probable reaction mechanism involves addition of hydrazine hydrate at the N-C2 bond, followed by elimination of ammonia and reduction of the nitro group to amino. 2-Amino-4-methyl-3-nitropyridine and 2-amino-5-methyl-3-nitropyridine reacted with hydrazine hydrate in a similar way.
An examination of the palladium/Mor-DalPhos catalyst system in the context of selective ammonia monoarylation at room temperature
Alsabeh, Pamela G.,Lundgren, Rylan J.,McDonald, Robert,Johansson Seechurn, Carin C. C.,Colacot, Thomas J.,Stradiotto, Mark
supporting information, p. 2131 - 2141 (2013/03/14)
An examination of the [{Pd(cinnamyl)Cl}2]/Mor-DalPhos (Mor-DalPhos=di(1-adamantyl)-2-morpholinophenylphosphine) catalyst system in Buchwald-Hartwig aminations employing ammonia was conducted to better understand the catalyst formation process and to guide the development of precatalysts for otherwise challenging room-temperature ammonia monoarylations. The combination of [{Pd(cinnamyl)Cl}2] and Mor-DalPhos afforded [(κ 2-P,N-Mor-DalPhos)Pd(η1-cinnamyl)Cl] (2), which, in the presence of a base and chlorobenzene, generated [(κ2-P,N- Mor-DalPhos)Pd(Ph)Cl] (1 a). Halide abstraction from 1 a afforded [(κ3-P,N,O-Mor-DalPhos)Pd(Ph)]OTf (5), bringing to light a potential stabilizing interaction that is offered by Mor-DalPhos. An examination of [(κ2-P,N-Mor-DalPhos)Pd(aryl)Cl] (1 b-f) and related precatalysts for the coupling of ammonia and chlorobenzene at room temperature established the suitability of 1 a in such challenging applications. The scope of reactivity for the use of 1 a (5 mol %) encompassed a range of (hetero)aryl (pseudo)halides (X=Cl, Br, I, OTs) with diverse substituents (alkyl, aryl, ether, thioether, ketone, amine, fluoro, trifluoromethyl, and nitrile), including chemoselective arylations. Copyright
Synthesis of some fluorine-containing pyridinealdoximes of potential use for the treatment of organophosphorus nerve-agent poisoning
Timperley, Christopher M.,Banks, R. Eric,Young, Ian M.,Haszeldine, Robert N.
, p. 541 - 547 (2011/09/15)
Fluoroheterocyclic aldoximes were screened as therapeutic agents for the treatment of anticholinesterase poisoning. 2-Fluoropyridine-3- and -6-aldoxime, and 3-fluoropyridine-2- and -4-aldoxime, were synthesised. Attempts to obtain 3,5,6-trifluoropyridine-2,4-bis(aldoxime) and -2-aldoxime, however, proved unsuccessful. Pentafluorobenzaldoxime was prepared by oximation of pentafluorobenzaldehyde. Acid dissociation constants (pKa) and second-order rate constants (kox-) of the fluorinated pyridinealdoximes towards sarin were measured. 2,3,5,6-Tetrafluoropyridine-4- aldoxime had the best profile: its kox- approached that of the therapeutic oxime P2S (310 vs. 120 l mol-1 min-1), but its higher pKa (9.1 vs. 7.8) fell short of the target figure of 8 required for reactivation of inhibited acetylcholinesterase in vivo. N-alkylation of the fluorinated pyridine-aldoximes may reduce their pK a nearer to 8 and enhance their therapeutic potential. Crown Copyright
Site-selective azaindole arylation at the azine and azole rings via N-oxide activation
Huestis, Malcolm P.,Fagnou, Keith
supporting information; experimental part, p. 1357 - 1360 (2009/09/05)
Subjection of N-methyl 6-and 7-azaindole N-oxides to a Pd(OAc) 2/DavePhos catalyst system enables regioselective direct arylation of the azine ring. Following deoxygenation, 7-azaindole substrates undergo an additional regioselective azole direct arylation event in good yield.
PYRAZOLE COMPOUND AND MEDICINAL COMPOSITION CONTAINING THE SAME
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Page/Page column 134, (2008/06/13)
The present invention provides a novel compound having an excellent JNK inhibitory effect. That is, it provides a compound represented by the following formula, a salt thereof or a hydrate of them. Wherein R1 designates -(CO)h-(NRa)j-(CRb=CRc)k-Ar (wherein Ra, Rb and Rc each independently designate a hydrogen atom, a halogen atom, hydroxyl group, an optionally substituted C1-6 alkyl group or the like; Cy designates a 5- or 6-membered heteroaryl; and V each independently designate the formula -L-X-Y (wherein L designates a single bond, an optionally substituted C1-6 alkylene group or the like; X designates a single bond or the formula -A- (wherein A designates NR2, O, CO, S, SO or SO2) and so on; and Y designates a hydrogen atom, a halogen atom, nitro group or the like).
Synthesis of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP)
Niu, Chuansheng,Li, Jun,Doyle, Terrence W.,Chen, Shu-Hui
, p. 6311 - 6318 (2007/10/03)
Palladium-catalyzed cross-coupling of methylboronic acid with 2-chloro- 3-nitropyridine produced 2-methyl-3-nitropyridine 4 in one step in high yield. Oxidation of 4 with selenium dioxide gave aldehyde 5. Alternatively, condensation of 4 with DMFDMA followed by oxidation gave 5 in a two step higher yielding conversion. Subsequent direct coupling of 5 with thiosemicarbazide followed by reduction of the nitro group using stannous chloride or sodium sulfide provided 3-AP (3). Reduction with sodium hydrosulfite gave 3-HAP (8). Finally a route which avoids the reduction of a nitro function was devised. Thus direct coupling of styrene with 2-chloro-3- aminopyridine 9 under Heck reaction conditions gave 16 which was converted to 17, oxidized to the aldehyde 18 and converted to 3-AP (3) with in situ deblocking of the t-Boc functionality.
The ortho effect in pyridines. Part XI(1). Substituent effects on basicity of 2- and 4-substituted 3-aminopyridines
Rasala, D.
, p. 79 - 84 (2007/10/02)
The substituent effects on the pKa values corresponding to the first protonation site of thirty 2- and 4-substituted 3-aminopyridines have been studied.It was found that the relative localized and delocalized effects are apparently sensitive to the variation of substituent position in the pyridine ring.An interaction of the 2-substituent with the protonation centre has mainly inductive character, whereas, the pKa values of 4-substituted 3-aminopyridines are highly affected by through-resonance.The steric effect was found to be insignificant.Keywords: substituent effects / 2- and 4-substituted 3-aminopyridines / basicity
Studies on 1,3-Benzoxazines. II. New Rearrangement Modes in the Reaction of 4-Chloro-2,2-dimethyl-2H-1,3-benzoxazine with Substituted Pyridine N-Oxides
Wachi, Kazuyuki,Terada, Atsusuke
, p. 3020 - 3028 (2007/10/02)
New rearrangement modes in the reaction of 4-chloro-2,2-dimethyl-2H-1,3-benzoxazine (1) with various α- and/or γ-substituted pyridine N-oxides are described.The benzoxazine moiety was introduced into the side chain and/or β-position of the pyridine ring, in addition to the α-position.Possible mechanism of the reactions are discussed.Keywords - 1,3-benzoxazine; picoline N-oxide; lutidine N-oxide; imidoyl chloride; rearrangement.
