Methylamine basicity

I. Tuhon, E. Silla, and J. Tomasi, ]. Phys. Chem., 96, 9043 (1992). Methylamines Basicity Calculations. In Vacuo and in Solution Comparative Analysis. 

Bromosafrole is a great stepping stone to final product and was, in fact, the exact precursor used by Merck who was the first person to synthesize MDMA. Until very recently it was the defacto method that most underground chemists started out with (Someone-Who-Is-Not-Strike included) because, at first glance, it seems so simple and uses basic chemicals and equipment. Once someone has the bromosafrole, all one has to do is just swap out that Br with simple ammonia or methylamine and the deed is done. 

Let us define the respective basicity by — AG in the gas phase and — AG" in aqueous solution. For discussions concerning the relative strength in basicity of a series of methyl-amines, only the relative magnitudes of these quantities are needed. Thus the free energy changes associated with the protonation of the methylamines relative to those of ammonia are defined as... 

Teloidine, the basic hydrolytic product of meteloidine, has been synthesised recently under physiological conditions by Schdpf and Arnold, on the lines of the tropinone synthesis, mesotartaric aldehyde (CHOH. CHO)j, being condensed at 25° with aeetonediearboxylic acid bnd methylamine hydrochloride to teloidinone (5-keto-l 2-dihydroxy-tropane) whieh on eatalytic hydrogenation yielded teloidine (1 2 5-trihydroxytropane). 

Diaryl-1,3,6-trimethyl-1,2,3,4,5,6,7,8-oetahydropyrido[4,3-reaction between methylamine, formaldehyde, and a l,l-diarylpropan-2-one in the presence of a basic... 

As already reported in Table 6, the solubility of phosphazene polymers is strongly influenced by the nature of the substituent groups attached at the phosphorus atoms along the -P=N- skeleton. Water-solubility, for instance, can be induced in polyphosphazenes by using strongly polar substituents (e.g. methylamine [84], glucosyl [495], glyceryl [496], polyoxyethylene mono-methylether [273] or sulfonic acid [497,498] derivatives), or may be promoted by acids or bases when basic (amino substituents like ethylamine [499]) or acid (e.g. aryloxy carboxylate [499] or aryloxy hydroxylate [295]) substituents are exploited. 

Base catalysis is another area which has received a recent stimulus from developments in materials science and microporous solids in particular. The Merk company, for example, has developed a basic catalyst by supporting clusters of cesium oxide in a zeolite matrix [13]. This catalyst system has been developed to manufacture 4-methylthiazole from acetone and methylamine. 

Oxime carbamates have high polarity and solubility in water and are relatively chemically and thermally unstable. They are relatively stable in weakly acidic to neutral media (pH 4-6) but unstable in strongly acidic and basic media. Rapid hydrolysis occurs in strongly basic aqueous solutions (pH > 9) to form the parent oxime/alcohol and methylamine, which is enhanced at elevated temperature. Additionally, oxime carbamates are, generally, stable in most organic solvents and readily soluble in acetone, methanol, acetonitrile, and ethyl acetate, with the exception of aliphatic hydrocarbons. Furthermore, most oxime carbamates contain an active -alkyl (methyl) moiety that can be easily oxidized to form the corresponding sulfoxide or sulfone metabolites. 

It appears that treatment of phenacyl bromides 1239 with methylhydrazine in refluxing acetic acid leads also to 1,4-disubstituted triazoles 1244. Fivefold excess of methylhydrazine is used in these reactions. According to the proposed mechanism, structures 1240-1243, methylhydrazine has a double role, as a condensing agent and an oxidant. In the final account, three molecules of methylhydrazine have to be used to produce one molecule of triazole 1244, two molecules of methylamine and one molecule of ammonia. The basic triazole 1244 (X = Y = H) is separated in 59% yield. The reactions go well with electron-donating substituents (for X = OH, the yield is 81%), but electron-withdrawing substituents can lower the yield dramatically (11% for X = N02) (Scheme 206) <2003JCM96>. 

The Chemicals Group markets over 7000 products. In addition to basic chemicals such as industrial salts, household salt, chlorine and methylamines, Akzo Nobel produces a wide range of special chemical products. 

Acetylgramine. This substance is active (IV. in mice) at doses of 5 mg per kg and less, making it quite potent. It potentiates response to DMPP (l,l-Dimethyl-4-phenylpiperazinium iodide) and blocks response to acetylcholine and adrenalin. Reflux a mixture of 15 g of 5-aeetylindole or analog (in equimolar amount), 7.55 g of 37% aqueous formaldehyde, 17 g of 25% aqueous di-methylamine, 25 ml of acetic acid, and 250 ml of methanol for 3 hours. Concentrate in vacuo to 20% of original volume, treat with 100 ml of water, wash with chloroform, chill in freezer, and make basic with 20% NaOH. Filter off the crystalline precipitate and wash with cold (near freezing) water to get a little over 17 g of the title product. Recrystallize from benzene to purify. It is unknown to me if this is active orally. 

The pATa values for the amines ammonia, methy-lamine, dimethylamine, and trimethylamine are 9.2, 10.6, 10.7, and 9.8 respectively. The electron-donating effect of the methyl substituents increases the basic strength of methylamine over ammonia by about 1.4 pATa units, i.e. by a factor of over 25 (10 " = 25.1). However, the introduction of a second methyl substituent has a relatively small effect, and the introduction of a third methyl group, as in trimethylamine, actually reduces the basic strength to nearer that of methylamine. 

It then becomes fairly easy to decide that methanol is not a strong acid, like nitric acid say, so that the pATa — 2.2 is unlikely to refer to its acid properties. Methylamine ought to be basic rather like ammonia, so the pATa value of 35 would appear well out of the normal range for bases and must refer to its acidic properties. In such cases, there appear to be very good reasons for continuing to use pATb values for bases unfortunately, however, this is not now the convention. 

Evidently the non-aqueous phase may possess acidic or basic characters either in virtue of its own properties, e.g. nitrobenzene and aniline, or through the addition of small quantities of soluble acidic or basic substances, e.g. salicylic acid to salicylaldehyde or methylamine to nitrobenzene. 

Aqueous methylamine (64 ml, 33.2 mmol) was added to 1,1 -bis(diphenylphospino) 2,2 -bis(a-acetoxyethyl)ferrocene (403 mg, 0.55 mmol) in isopropanol (5 ml) and the reaction mixture was stirred in a closed pressure ampoule at 90°C for 66 hours. After evaporation in vacuo, the residue was dissolved in ethyl acetate/heptane 1 1 and extracted with 10% aqueous citric acid. The aqueous phase was washed with ethyl acetate/heptane 1 1, basified with 2N NaOH basic and... 

If the final mixture is acidic, indicating excessive loss of methylamine, sufficient methylamine should be added to render the mixture basic. This situation is more likely to occur in smaller runs (0.1-0.2 mole). 

Photoluminescence experiments with ni-V wafers of Ino.5o(Gao.9o A1o.io)o.5oP were conducted 114]. The Lewis basic gaseous analytes ammonia, methylamine, dimethyl amine, and trimethylamine all yielded reversible PL enhancements. The Lewis acid sulfur dioxide, in contrast, caused reversible quenching of the semiconductor s PL intensity. These PL intensity changes were consistent with analyte-induced modifications of the dead-layer thickness. 

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