7-Methylamino pyridine

As a catalyst for ester and amide formation from acyl chlorides or anhydrides, 4-(di-methylamino)pyridine has been recommended (DMAP G. Hdfle, 1978). In the presence of this agent highly hindered hydroxyl groups, e.g. of steroids and carbohydrates, are acylated under mild conditions, which is difficult to achieve with other catalysts. 

Dinitro-6-methylamino-l,2,3,4-tctrahydro-aus 3,5-Dinitro-2-methylamino-pyridin und Natriumboranat, danach SalzsauTe 90... 

Diamino-6-[(2,4,6-trimethylphenyl)methylamino]pyridine was reacted with EMME in boiling dioxane for 30 min to give 3-pyridylamino-methylenemalonate (169) in 73% yield (79CZ387). 

A similar C-N interchange has also been reported with 3,5-dicyano-I,2,6-trimethylpyridinium salts (121), leading to the formation of 3-acetyl-2-(methylamino)pyridine derivative 122 (Scheme IV.48) (95T8599). 

Me2bsb = bidentate Schiff base (73) with Ri mini = methylglyoxalbismethyleneimine, MeN= nta = nitrilotriacetate oep = octaethylporphyrin phen= 1,10-phenanthroline, (71) pic = 2-picolylamine = 2-(methylamino)pyridine Py = pyridine pz = pyrazine... 

Condensation of 3-amino-2-(methylamino)pyridine 647 with diethyl 2-oxomalonate in boiling ethanol afforded 2-carbethoxy-4-methylpyrido[2,3- ]pyrazin-3(4//)-one 213 <1996JHC1737>. On the other hand, condensation of 647 with diethyl oxaloacetate gave ethyl [2(l//)-oxopyrido[2,3- ]pyrazine-3(4//)-ylidene]carboxylate 648 in addition to the formation of pyridodiazepine 649 as a by-product <1996JHC1737>. However, the condensation of 647 with diethyl 2-oxoadipate gave the 2-ethoxycarbonylpropyl analogue 650 (Scheme 30) <1994FA259>. 

Scheme 18. Synthesis of the oligo[2]catenands 52 (i) 4-(di-methylamino)pyridine-p- tolu-enesulfonic acid 1 1 complex plus /V,/V -diisopropylcarbodi-imide.

Thorpe-Ziegler synthesis of 3-aminoindoles with additional functional groups was used as part of the synthesis of condensed indoles [e.g., azepines (94) were obtained from 3-amino-2-benzoylindoles (93) (91JHC379) (Scheme 24)]. In these cases the nature of the substituent R is important for a smooth reaction (Ac < Bz < 2-N02-benzoyl, but no reaction when R = H). With 2-chloro-3-(/V-bromoacetyl-/V-methylamino)pyridine and o-benzoylaminobenzonitriles (95), the condensed pyridodiazepinones 97 and 99 (95H753) were obtained via intermediates 96 and 3-aminoindoles intermediate (via 98) 3-aminoindoles followed by substitution of the 2-chloro substituent by the resulting 3-amino group (Scheme 25). 

A 13C—NMR study of several dimethylamino derivatives of pyridine, pyrimidine, and 2-oxopyrimidine with and without o-methyl substitution indicates a progressive twist of the dimethylamino group in hindered derivatives (78JCS(P2)1119). Unfortunately, the barriers have not yet been determined. The free energy of activation for 4-(Af-methylamino)pyridine (80JCS(P2)1704) is AG = 42.6 kJ mol-1 and is close to that of N-methyl-4-nitroaniline. 

Corma, A., Garcia, H., Leyva, A. Heterogeneous Bayiis-Hiiiman using a polystyrene-bound 4-(N-benzyl-N-methylamino)pyridine as reusable catalyst. Chem, Commun, 2003, 2806-2807. 

In 1993, Vedejs et al. [5,6] showed that tributylphosphine is a potent catalyst for the acylation of alcohols by acetic and benzoic anhydrides as efficient as 4-(di-methylamino)pyridine DMAP [7,8]. However, the DMAP catalyst is more versatile since it presents catalytic activity in the reaction of alcohols with a larger variety of electrophiles. Due to these properties, Fu [9] realized the design and synthesis of a new family of chiral nucleophilic catalysts illustrated by the planar-chiral DMAP derivative I which is a very efficient catalyst in different enantioselective reactions such as addition of alcohols to ketenes [10], rearrangement of O-acylated azalactones [11], and kinetic resolution of secondary alcohols [12-14]. 

The polymer-supported 4-(A -methylamino)pyridine (Figure 3.4), prepared by reaction of 4-chloromethylstyrene and 4-(methylamino)pyridine sodium salt and successive copolymerization with styrene and divinyl benzene,was utilized as reusable catalyst for promoting the Baylis-Hillman reaction usually this kind of reaction uses stoichiometric or overstoichiometric amounts of an organic amine as a base catalyst. 

The starting material used in the following method is prepared by converting 2-aminonicoti-nonitrile with dimethylformamide dimethyl acetal into 2-[(A,V-dimethylamino)methylamino]-pyridine-3-earbonitrile followed by hydroxylamine to give the 2-[(hydroxyimino)methylarnino]-pyridine-3-carboxamidoxime.14 Cyclization of the latter on heating with polyphosphoric acid yields pyrido[2,3-[Pg.86]

A solution of NH2OH [prepared fromNH2OH HC1 (1.4 g, 20 mmol) and a solution of Na (0.46 g, 20 mmol) in MeOH (30 mL)] was treated with 2-[(dimethylamino)methylamino]pyridine-3-carbonitrile (0.87 g, 5 mmol). After standing overnight at rt the solvent was evaporated, the residue treated with some H20, and the product collected yield 0.7 g (72%) mp 190 205 °C (with cyclization into pyrido[2,3-4]pyrimidin-4-amine 3-oxide mp 270-275 CC). 

When 3-cyano-l-methylpyridinium iodide (X) is heated in 2 N aqueous NaOH together with methylamine hydrochloride, 2-(methylamino)pyridine-3-carbaldehyde (A) is formed in 60% yield. 

In a recent paper, the protected a-D-glucofiiranose (1) was selected as a carbohydrate model compound by Oscarson et al. [5] for acetylation, under the action of microwave irradiation, with acetyl chloride (2 equiv.) and pyridine, N,N-(diisopropyl)aminoethylpolystyrene (PS-DIEA), or N-(methylpolystyrene)-4-(methylamino)pyridine (PDS-DMAP) as conventional bases. The acetyl derivative 2 was produced in good to excellent yields in a very short time (Scheme 12.1). 

The method developed by Garegg et al. [14] to form benzylidene acetals was modified by Oscarson et al. [5], who treated compound 9 with benzal bromide and N-(methylpolystyrene)-4-(methylamino)pyridine (PS-DMAP) in acetonitrile under microwave irradiation conditions to form the 4,6-O-benzylidene derivative 20 (83%) after 5 min (Scheme 12.9). 

Silylation of the 3-hydroxyl group of 1 was achieved by Oscarson [5], who used tert-butyldimethylsUyl chloride (TBDMSCl) in the presence of pyridine or N-(methylpolystyrene)-4-(methylamino)pyridine (PDS-DMAP), in a Smith Synthesizer (Scheme 12.12). In addition to the silylated product 32a, the secondary product 33a, formed by acetal migration, was also observed. 

---