4-Methoxy-3- pyridin

The 2-nitration of 3-hydroxy- and 3-methoxy-pyridine in 85-96% sulphuric acid involves the conjugate acids, whilst the 3-nitration of 6-hydroxy and 6-methoxy-2-pyridone in 70-77 % sulphuric acid involves the free bases, which react at, or near to the encounter rate. ... 

In their acidity, basicity, and the directive influence exerted on electrophilic substitution reactions in benzenoid nuclei, acylamino groups show properties which are intermediate between those of free amino and hydroxyl groups, and, therefore, it is at first surprising to find that the tautomeric behavior of acylaminopyridines closely resembles that of the aminopyridines instead of being intermediate between that of the amino- and hydroxy-pyridines. The basicities of the acylaminopyridines are, indeed, closer to those of the methoxy-pyridines than to those of the aminopyridines, the position of the tautomeric equilibrium being determined by the fact that the acyl-iminopyridones are strong bases like the iminopyridones and unlike the pyridones themselves. Thus, relative to the conversion of an... 

The scope of reactions involving hydrogen peroxide and PTC is large, and some idea of the versatility can be found from Table 4.2. A relatively new combined oxidation/phase transfer catalyst for alkene epoxidation is based on MeRe03 in conjunction with 4-substituted pyridines (e.g. 4-methoxy pyridine), the resulting complex accomplishing both catalytic roles. 

Kinetic parameters k, often also and AS, occasionally AV ) for formation and dissociation of several pentacyanoferrate(II) complexes [Fe(CN)5L]" have been established. Ligands L include several S- and A-donor heterocycles,4-methyl- and 4-amino-pyridines, a series of alkylamines, 3- and 4-hydroxy- and 3- and 4-methoxy-pyridines, several amino acids, nicotinamide, " 4-pyridine aldoxime, 3-Me and 3-Ph sydnones, several bis-pyridine ligands,neutral, protonated, and methylated 4,4 -bipyridyl, 1,2-bis(4-pyridyl)ethane and traTO-l,2-bis0-pyridyl)ethene, pyrazine- 4,4 -bipyridyl- and bis(4-pyridyl)ethyne-pentaammine-cobalt(III), edta-ruthenium(III), and pentaammineruthenium-(II)and-(III) complexes of... 

Fe-Staub/CaCl2/C2H5OH (15% HaO) RuckfluB 2 h 5-Amino-2-methoxy-pyridin 97 4... 

The 4-pyridones behave similarly, with the neutral tautomer reacting below pH 6 and the anion at higher pH. The observation that 4-methoxy-pyridine shows little comparative reactivity over the whole range is evidence that the hydroxy tautomer is not involved in the bromination process. Again, once the first bromine has entered the ring, further bromination occurs more readily because of easier anion formation (83CJC2556). 

Fig. 4a,b. Electric field maps (Volt/nm) of hydrogen bond accepting molecules a 4-methoxy pyridine b H3CH2COCH2CH3... 

MOPO 4-methoxy, pyridine-N-oxide HDBM dibenzoyl methane... 

Indirect support for this hypothesis has now been obtained. Phenyla-tion of 3-cyclohexyl pyridine with phenyllithium gave a 2,3-/2,5-isomer ratio of 65 35.2460 The cyclohexyl radical is expected to be at least as bulky as a phenyl radical. The exclusive formation of the 2,3-isomer in the reaction of phenyllithium both with 3-amino- and 3-methoxy-pyridine has been attributed to the formation of a complex such as 111 between the lone-pair of electrons on the 3-substituent and the lithium atom, in which the phenyl group would be suitably... 

A need for a synthetic entry toward simple and structurally complex alkaloids prompted development of methodology to prepare a variety of azabicyclo[n.3.1] alkenes in good yields utilizing protected 2,6-cA-diaIkenyl piperidines, prepared from glutarimide or 4-methoxy pyridine and catalyzed by (2a) and (4a) (equation 1)." " ... 

There are many example of direct hthiation with the assistance of ortfto-directing groups. Halo-, particularly chloro-, or better, fluoro-pyridines, but even bromo-pyridines undergo hthiation ortho to the halogen, nsing lithinm di-wo-propylamide. 3-Halopyridines react mainly at C-4, and 2- and 4-halo-pyridines necessarily hthiate at a P-position. In the hthiation of methoxy-pyridines, using mesityllithium the 3-isomer metahates at C-2, whereas 3-methoxymethoxypyridine, 3-di-/xo-propylaminocarbonyl- ... 

Aus 2-Methoxy-pyridin bildet sich dagegen iiber Platin in 40%-iger Essigsaure, in waGriger Salzsaure sowie in chlorwasserstoff-haltigem Methanol unter Hydrogenolyse der C-O-BindungPiperidin3. 2-Methoxy-5-[N-athyl-N-(2-methyl-propenyl)-amino]-pyridin liefert 3-[N-Athyl-N-(2-methyl-propyl)-amino]-piperidin (70% d.Th,)4 ... 

Methoxy-pyridin laBt sich iiber Raney-Nickel bei 1507150 bar zu3-Methoxy-pi-peridin umsetzen5, sein 2-(2-Hydroxy-propyl)-Derivat wird iiber Platin(IV)-oxid in Essigsaure (7072-3 bar) zu 74% d.Th. zum 3-Methoxy-2-(2-hydroxy-propyl)-piperidin hydriert6. Einige 3-Methoxy-4-pyridone werden mit Raney-Nickel bei 15 57110 bar zu den 4-Hydroxy-3 -methoxy -piperidinen hydriert7. 

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