Aliphatic series

This reaction is precisely parallel to the Wurtz Reaction in the aliphatic series, by which, for instance, n-butane can be obtained by the action of sodium on ethyl bromide. 

Tertiary aliphatic - aromatic amines, unlike those of the aliphatic series, react with nitrous acid with the formation of G-nitroso compounds the nitroso group enters almost exclusively in the para position if available, otherwise in the ortho position. Thus dimethylaniline yields />-nitrosodiniethylaniline ... 

The procedures as outlined are applicable to both the aliphatic and aromatic series. They are superior to the common interchange method in that they avoid the fractional distillation which is very troublesome in the aliphatic series. They have been used in numerous instances and can be adapted to give mixed anli3"drides. Benzoic anhydride has been obtained, by closely related procedures, from benzoic acid and benzoyl chloride by heating under reduced pressure or in the presence of zinc chloride. 

Figure 4. Graph of Log(V r) against Number of Methylene Groups for Different Aliphatic Series...

In fact, this procedure can be used for any aliphatic series such as alcohols, amines, etc. Consequently, before dealing with a specific homologous series, the validity of using the methylene group as the reference group needs to be established. The source of retention data that will be used to demonstrate this procedure is that published by Martire and his group [5-10] at Georgetown University and are included in the thesis of many of his students. The stationary phases used were all n-alkanes and there was extensive data available from the stationary phase n-octadecane. The specific data included the specific retention volumes of the different solutes at 0°C (V r(To)) thus, (V r(T)) was calculated for any temperature (Ti) as follows. 

Because osmium tetroxide is expensive, and its vapors are toxic, alternate methods have been explored for effecting vic-glycol formation. In the aliphatic series, olefins can be hydroxylated with hydrogen peroxide with the use of only a catalytic amount of osmium tetroxide. Anhydrous conditions are not necessary 30% hydrogen peroxide in acetone or acetone-ether is satisfactory. The intermediate osmate ester is presumably cleaved by peroxide to the glycol with regeneration of osmium tetroxide. When this reaction was tried on a A -steroid, the product isolated was the 20-ketone ... 

The halog en derivatives of the aromatic hydrocarbons, like those of the aliphatic series, are colourless licjuids or solids, denser than water, and possessing an agreeable smell, unless the side-chain is substituted. The latter substances can often be distinguished by their irritating action on the eyes and mucous membrane of the nose (see Prep. 86, p. 194). 

Several improved methods for the preparation of known unsaturated azlactones as well as some interesting new compounds of this type have been reported. Crawford and Little observed that the direct use of 2-phenyl-5-oxazolone (1) in the Erlenmeyer reaction gave much improved yields (35-74%) of unsaturated azlactones with aliphatic aldehydes and with ketones such as acetone and cyclohexanone [Eq, (1)], The usual procedure of mixing a carbonyl compound, hippuric acid, acetic anhydride, and sodium (or lead) acetate affords poor yields in the aliphatic series. 

Habisch " investigated the action of chloramine on simple Schiff s bases. In the aliphatic series, diaziridine formation was observed in all the cases investigated. Ethereal solutions of chloramine react with Schiff s bases at room temperature within a few hours [Eq. (32)]. Table VI gives details of a few of the 1-alkyl-diaziridines prepared. 

The next group of alcoholic bodies to be studied are those which, although open-chaini alcohols, show considerable tendency to easily pass into closed-chain compounds, so that they occupy a definite position of their own, midway between the ordinary aliphatic series and the closed-chain series. The principal members of this important group are geraniol, nerol, linalol, and citronellol, together with the so-called aliphatic sesquiterpene alcohols, farnesol and nerolidol. 

Formic Aldehyde.—This aldehjde, H. CHO, is the lowest member of the aliphatic series. It has been found, but rarely, in the distUlation waters of a few essential oils. It can be identified by evaporation on a watsr-bath with ammonia when crystals of hexamethylene-tetramine are formed. 

Fett-reihe, /. fatty series, aliphatic series, -reservemittel, n. fat resist, wax resist, -rest, m. fat residue fatty residue, -salbe, /. fatty ointment. 

In the aliphatic series, hydrogenation of y-nitroketones gives pyrrolidines in good yields (52) and tx-nitroketones give a mixture of pyrazines and piperazines (i5). 

Among the polymeric stabilizers may be listed poly-condensed polymers based on alkyl phenols, aldehydes, and ketones of the aliphatic series, where = 1 - 8 and R,R means alkyl [24], Na, K, Ca phenolates of poly-condensed polymers [25], and also products of epichlor-ide with one or more aliphatic amines C3—C30 [26]. 

In the poly(alkylene arylate) series, Tm decreases with increasing length of flexible — (CH2) — moieties and, as in the aliphatic series, approaches the limiting value of polyethylene melting point for large n values (Table 2.6). Aromatic -aliphatic polyesters with even numbers of methylene groups melt at higher... 

KSIEs for the reaction of aromatic olefins, 1,1-diphenylethylene and a-methylstyrene (Table 21) are significantly smaller they can be related to transition states earlier than those in the aliphatic series. Unfortunately, for the reactions of highly reactive aromatic olefins or enol ethers, whose low sensitivity to solvent and substituent effects indicates very early transition states, there are not enough KSIE data to confirm this conclusion. 

Polar-substituted alkenes where the functionality is not attached to a strained ring are considerably more discriminating in their compatibility with metathesis catalysts and as a rule require relatively high catalyst charges. In the aliphatic series, unsaturated esters have received the most attention. Boelhouwer reported in 1972 the metathesis of the ester methyl oleate and its trans isomer, methyl elaidate, with a homogeneous catalyst based on a 1/1.4 molar combination of WCl6/(CH3)4Sn (23). At 70°C and an ester/W molar ratio of 33, near-thermodynamic equilibrium was attained, and 49 and 52% of the respective esters were converted to equal amounts of 9-octadecene and the dimethyl ester of 9-octadecene-1,18-dioic acid. 

A similar pattern had been observed earlier with p-phenyl-substituted carbocations. Relative migration ability of phenyl and substituted phenyl groups were determined for the first time, not by focusing on carbocations formed via aliphatic series as structural models, but rather by studying 9-ary 1-9,10-dimethylphenanthrenium ions (18, 19). 

Undiluted halogen compounds of the aliphatic series, such as ethyl bromide, chloroform, bromoform, and the like, should not be brought into contact with metallic sodium or potassium thus they must not be dried with these metals since very violent explosions may occur as a result of detonation (Staudinger). 

If it is desired to compare bromobenzene with a halide of the aliphatic series, the saturated ethyl bromide must naturally not be chosen... 

Reaction with Carbon Bisulphide.—Ammonia and the primary amines of the aliphatic series combine with carbon bisulphide to form ammonium salts of dithiocarbamic acids, e.g. 

In order to obtain an isothiocyanate in the aliphatic series, a dithiocarbamate must be distilled with a salt of a heavy metal (HgCl2, FeCl3) (A. W. Hofmann). Here, in the case of diphenylthiourea, the distillation is carried out with concentrated hydrochloric acid. 

Apart from rare exceptions, the only nitroso-compounds known are those in which the NO-group is united to a tertiary carbon atom, as in nitrosobenzene. Nitrosoisobutane (H3C)3 C.NO, for example, is a representative from the aliphatic series. 

For preparative purposes the method of obtaining aldehydes from the primary alcohols is preferable by far, at least in the aliphatic series. The simple aromatic aldehydes can be obtained by alkaline hydrolysis of the arylidene chlorides, R.CHC12, which are produced from the hydrocarbons by substitution with chlorine (technical method for the preparation of benzaldehyde). In addition to these methods the elegant synthesis of Gattermann and Koch should be mentioned here. This synthesis, which proceeds like that of Friedel-Crafts, consists in acting on the aromatic hydrocarbon with carbon monoxide and hydrogen chloride in the presence of aluminium chloride and cuprous chloride. 

In the case of tertiary aldehydes, which cannot undergo the aldol condensation, the Cannizzaro reaction replaces it also in the aliphatic series. Thus glyoxylic acid is disunited into glycoUic and oxalic acids. 

The reason why the acyloin synthesis is especially characteristic of aromatic aldehydes, depends on the circumstance that in the aromatic series the tertiary carbon atom in the ring does not allow of the aldol condensation, a reaction for which conditions are otherwise much more favourable. The simplest example of the acyloin condensation, moreover, was already encountered in the case of formaldehyde (p. 218) glycollic aldehyde is the simplest acyloin. Acyloin compounds are also produced, in the aliphatic series, by the action of sodium or potassium on esters, and hence are also formed as by-products in the acetoacetic ester synthesis (Bouveault, Scheibler). 

The methylene groups of hippuric acid and malonic acid are much more reactive than that of acetic acid. They may be caused, therefore, to condense with aldehydes under much milder conditions, e.g. by the action of pyridine. The use of malonic acid forms an extension of Perkin s reaction to the aliphatic series (Doebner), e.g. 

By their properties and reactions the phenols are very clearly distinguished from the ordinary alcohols of the aliphatic series. The fundamental difference between the two classes of compounds is that the OH-group of the phenols is attached to a doubly bound C-atom. The phenols, therefore, behave like the similarly constituted enols, as may be deduced from the following formulae ... 

From all these facts it can be deduced that the phenols are much more closely related to the carboxylic acids than to the alcohols of the aliphatic series. 

The simple primary amines of the aliphatic series, then, do not form diazo-compounds because the reaction which would le, d to their formation only occurs at a temperature at which they are destroyed. The reactivity of the NH2-group can, however, be increased by a neighbouring carbonyl group. Thus we come to the case of the esters of the a-amino-carboxylic acids and of the a-amino-ketones. The ethyl ester of glycine can be diazotised even in the cold the diazo-compound which does not decompose under these conditions undergoes stabilisation by elimination of water and change into ethyl diazoacetate ... 

Here we encounter a specific property of the aromatic compounds. In the aliphatic series diazonium salts are unknown because here substances of the aniline type —C=C— cannot exist. 

It has been found that in the case of equilibrium 30 the corresponding aliphatic series exhibit decreased pK values by about 5 pK units146. 

Structure effects on hydrogenation rate also have been studied in series of cycloalkenes. The influence of substituents on C=C is similar to that in aliphatic series (e.g., 52, 57, 90), but the point of interest is the observed... 

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