2,4,6-Trimethyl pyridine

This reaction consists of the condensation of two molecular equivalents of a 1,3 diketone (or a J3-keto-ester) with one equivalent of an aldehyde and one of ammonia. Thus the interaction of ethyl acetoacetate and acetaldehyde and ammonia affords the 1,4-dihy dro-pyridine derivative (1), which when boiled with dilute nitric acid readily undergoes dehydrogenation and aromatisation" to gb e the diethyl ester of collidine (or 2,4,6-trimethyl-pyridine-3,5 dicarboxylic acid (II)). For the initial condensation the solid aldehyde-ammonia can conveniently be used in place of the separate reagents. 

To a 1 mM soln of the linear peptide in DMF were added HATU (1 equiv) and 2,4,6-trimethyl pyridine (2 equiv). The mixture was stirred at rt and the reaction monitored by HPLC. Upon completion, the solvent was removed and the resulting residue redissolved in MeOH and precipitated with EtOAc/Et20. The product was worked up by standard procedures. 

On the basis of CNDO/2 calculations on the model compounds 2.4.6-trimethyl-pyridine and 2.4.6-tri-methyl-X -phosphorin, Schweig and coworkers found that the MO sequences of pyridine and X -phosphorin do not correspond to each other. For simplicity, methyl- rather than tert-butyl groups were used in the calculations (whereas the PE and UV spectra of the tert-butyl compounds have been recorded the synthesis of the unsubstituted X -phosphorin was unknown at the... 

Preparation 181.—Potassium Collidine Dicarboxylate (Dipotassium-2 4 6-trimethyl-pyridine - 3 5-dicarboxylate). 

Fig. 6.5. Typical potentiometric (1,2,3,4) and conductometric (r,2, 3, 4 ) titration curves forCB SAE-30 Marinol engine oils. Plots fresh oil (4,4 ), used oils (1,1 2,2 3,3 ). Medium toluene (50%), 2-propanol (47.5%), water (2.5%), v/v mixture. The end-point = (2,4,6-trimethyl-pyridine + HC1). The empirical potential, E, obtained from samples for which a sharp inflection occurs (see curve 4), and is substituted for the potential to determine the end point (Fox et al.,...

L = 2,6-dimethylpyridine X-oxide, 2,4,6-trimethyl-pyridine -oxide L = selenourea R = Me or Et... 

Bases that can be used include carbon monoxide and 2,4,6-trimethyl-pyridine (97). This reaction has been further studied (99) with the report that ira y-[PtH(PPh2Me)2(Me2CO)]PF6 reacts with C2H4 at — 50° to give frawr-[PtH(PPh2Me)2(C2H4)]PF6 (XLIV). The proposal that compounds similar to (XLIV) are the intermediates in the insertion reaction is further strengthened by the observation that when this reaction is carried out at room temperature rather than at —50° the... 

When more bulky base molecules(collidine 2,4,6-trimethyl-pyridine) were introduced on acid-type zeolites, only H-ZSM5 did not interact with collidine. The results suggest that all the acidic sites of H-ZSM5 are located in the channels but not on the outer surfaces. 

Trimethyl-pyridin wird besonders leicht partiell chloriert, der Ersatz samtlicher Wasserstoffatome erfordert eine langore Chlorierung bei erhohter Temperatur, wobei jedoch schon Chlorolyse als Nebenreaktion auftreten kann8. 

Riddick, D.S., S.S. Park, H.V Gelboin, and G.S. Marks (1990). Effects of 4-alkyl analogues of 3,5-diethoxycarbonyl-1,4-dihydro-2,4,6-trimethyl-pyridine on hepatic cytochrome P-450 heme, apoproteins, and catalytic activities following in vivo administration to rats. Mol. Pharmacol. 37, 130 136. 

Pyrylium Salts.—Acetylation of isoparaffins, such as (68), under Friedel-Crafts conditions at low temperatures produces pyrylium salts (69). The ratio of reactants and the presence or absence of chloroform as a solvent affect the yield of the mixture of isomers which is often obtained, through the intermediacy of a carbenium ion. The pyrylium salts were converted into pyridines (70) by aqueous ammonia. However, 3-methylpentane gave only 3-ethyl-2,4,6-trimethyl-pyridine. 

Although they are not as widely used as pyridine, substituted pyridines have found their own place in the characterization of hydroxyl groups. It was proposed (470) that, for steric reasons, 2,6-dimethylpyridine (DMP, lutidine) does not interact with Lewis acid sites and is thus a proton-specific probe. Later, it was demonstrated that DMP (247,256,471-473) (as well as 2,4,6-trimethyl pyridine or collidine (474)) stiU forms coordination bonds with coordinatively unsaturated surface cations. This bond is only weakened by the steric interference of the methyl groups with the surface but not prevented. In any case, the steric hindrance leads to preferential interaction ofDMP with hydroxyl groups (471-473). DFT calculations suggest that the proton transfer is promoted by the stabilization of the lutidinium ion on the deprotonated site, rather than by the intrinsic acidity of the acid site itself (475). 

Propyne added at -40° to a mixture of excess acetonitrile and cobaltous chloride hexahydrate, then NaBH4 added with stirring, the cooling bath removed, the temp, allowed to rise to -20°, after 20 min. transferred at -30° to an evacuated steel autoclave, heated during ca. 30 min. to 80°, and the products isolated when the pressure has decreased from 7 to 1 atm. during 4 hrs. 2,4,6-trimethyl pyridine... 

Praill, having discovered the efficiency of acylium perchlorates as acylating agents, decided to examine the esterification of /err-butanol as opposed to its dehydration to isobutene. Using acetic anhydride and perchloric acid mixtures, both tert-h xty acetate and isobutene were rapidly produced and in accordance with the known alkyl oxygen fission of tertiary esters, the proportion of isobutene increased with time. In these reactions where acetic anhydride was in excess, crystalline material was deposited in the mixture. Later this was shown to be 2,4,6-trimethylpyrylium perchlorate, identified by its conversion to 2,4,6-trimethyl pyridine and its picrate. When isobutene itself was acylated using acetic anhydride and perchloric... 

Trimethyl Pyridine (y Collidine) ((CH3)jC5H2N) —(mol weight 121.18), (Warning—See Note 8) conforming to the following requirements ... 

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