Naming compounds aldehydes

Acetaldehyde [75-07-0] (ethanal), CH CHO, was first prepared by Scheele ia 1774, by the action of manganese dioxide [1313-13-9] and sulfuric acid [7664-93-9] on ethanol [64-17-5]. The stmcture of acetaldehyde was estabhshed in 1835 by Liebig from a pure sample prepared by oxidising ethyl alcohol with chromic acid. Liebig named the compound "aldehyde" from the Latin words translated as al(cohol) dehyd(rogenated). The formation of acetaldehyde by the addition of water [7732-18-5] to acetylene [74-86-2] was observed by Kutscherow] in 1881. 

The initial carbon-carbon bond formation (— 84) is often reversible, and a subsequent step—such as dehydration—may be necessary to displace the equilibrium. The many different (often named) reactions really differ from each other only in the nature of the particular carbonyl compound (aldehyde, ketone, ester, etc.), and in the type of carbanion, employed. 

Like the other organic compounds you have encountered, the names of aldehydes and ketones are based on the names of the parent alkanes. 

In certain polyfunctional compounds, an aldehyde or ketone group can also be named as a substituent on a molecule with another functional group as its root. The aldehyde carbonyl is given the prefix formyl-, and the ketone group is named 0x0- with a number to show its position in the molecule. Compounds with both an aldehyde and ketone are named as aldehydes, because aldehydes have functional group priority over ketones. A ketone containing a benzene ring is named as a -phenone. 

The IUPAC system employs a series of rules to formulate compound names. The following rules explain how to name aliphatic aldehydes ... 

The reaction mechanism on a vanadia-titania catalyst has been re-investigated using FTIR spectroscopy [114], although the conclusions were not markedly different from earlier proposals. The interaction of methylpyrazine with the catalyst surface involves a consecutive transformation of co-ordinatively bound methylpyrazine into oxygenated surface compounds, namely an aldehyde-like complex and an asymmetric carboxylate. The main reaction product, amidopyrazine, is formed through the interaction of the surface oxy-intermediates with adsorbed ammonia species. 

Select From pubchem.compound Where iupac name Like %aldehyde% And heavy atom count < 20 ... 

It is interesting that systematic investigations on reactions of aliphatic diazo compounds with simple aldehydes and ketones were conducted relatively late, namely in the early 1970 s. Schollkopf and Frasnelli (1970) demonstrated that, using metallated diazocarbonyl compounds, aldehydes form aldols in excellent yields (>90 o), as shown in (9-8) for the example of benzaldehyde. Later, Schollkopf et al. (1974) showed that the metallation step is not necessary when organometallic bases, such as butyllithium are present in the aprotic, nonpolar system (e. g., in ether-THF-hexane). The method can be generalized for many aldehydes and ketones, even with KOH as base (Schollkopf and Scholz, 1976). 

In naming compounds that contain more than one functional group, the lUPAC system has established an order of precedence of functional groups. If the carbonyl group of an aldehyde or a ketone is lower in precedence than other functional groups in the molecule, it is indicated by the infix -0x0-. 

The values of the nitro-, dirdtro- and trinitrotoluene isomers and of some oxidation and reduction products of a-(2,4,6-)trinitro-toluene (= 8t) are referred to this last named compound. Ethyl acetate-petrol ether (15 + 85) and 1,2-dichloroethane-petrol ether (25 + 75) were the solvents used in the 1st and 2nd directions respectively. The-substances were visualised by spraying with the 4-diethylaminobenz-aldehyde reagent, yielding yellow, brown or red spots (Fig. 187). 

Compounds containing two ketones are diones. As with dials, the final e of the parent alkane is retained, and the name begins with the position numbers of the two carbonyl groups (Fig. 16.10). Ketoaldehydes are named as aldehydes, not ketones, because the aldehyde group has a higher priority than a keto group (Fig. 16.10). 

Alternative treatment of the sulfoxide with aldehydes in the presence of tetra-w-butylammonium fluoride gives the phenyl-sulflnylcarbinol and thence the phenylthiocarbinol following reduction. The two last-named compounds are intermediates in the synthesis of cyclobutanones and cyclobutenes, respectively (eqs 3 and 4).2h,2c,2e... 

Like aldehydes ketone functions take precedence over alcohol functions double bonds halogens and alkyl groups m determining the parent name and direction of numbering Aldehydes outrank ketones however and a compound that contains both an aldehyde and a ketone carbonyl group is named as an aldehyde In such cases the carbonyl oxy gen of the ketone is considered an 0x0 substituent on the mam chain... 

It IS hard to find a class of compounds in which the common names of its members have influenced organic nomenclature more than carboxylic acids Not only are the common names of carboxylic acids themselves abundant and widely used but the names of many other compounds are derived from them Benzene took its name from benzoic acid and propane from propionic acid not the other way around The name butane comes from butyric acid present m rancid butter The common names of most aldehydes are derived from the common names of carboxylic acids—valeraldehyde from valeric acid for exam pie Many carboxylic acids are better known by common names than by their systematic ones and the framers of the lUPAC rules have taken a liberal view toward accepting these common names as permissible alternatives to the systematic ones Table 19 1 lists both common and systematic names for a number of important carboxylic acids... 

Nitriles contain the —C=N functional group We have already discussed the two mam procedures by which they are prepared namely the nucleophilic substitution of alkyl halides by cyanide and the conversion of aldehydes and ketones to cyanohydrins Table 20 6 reviews aspects of these reactions Neither of the reactions m Table 20 6 is suitable for aryl nitriles (ArC=N) these compounds are readily prepared by a reaction to be dis cussed m Chapter 22... 

Acetals and Acylals. Acetals, which contain the group >C(OR)2, where R may be different, are named (1) as dialkoxy compounds or (2) by the name of the corresponding aldehyde or ketone followed by the name of the hydrocarbon radical(s) followed by the word acetal. For example, CH3—CH(0CH3)2 is named either (1) 1,1-dimethoxyethane or (2) acetaldehyde dimethyl acetal. 

When the aldehyde group is directly attached to a carbon atom of a ring system, the suffix -carbaldehyde is added to the name of the ring system, e.g., 2-naphthalenecarbaldehyde. When the aldehyde group is separated from the ring by a chain of carbon atoms, the compound is named (1) as a derivative of the acyclic system or (2) by conjunctive nomenclature, for example, (1) (2-naphthyl)propionaldehyde or (2) 2-naphthalenepropionaldehyde. 

For oximes, the word oxime is placed after the name of the aldehyde or ketone. If the carbonyl group is not the principal group, use the prefix hydroxyimino-. Compounds with the group Z = N—OR are named by a prefix alkyloxyimino- as oxime O-ethers or as O-substituted oximes. Compounds with the group r C=N(0)R are named by adding A-oxide after the name of the alkylideneaminc compound. For amine oxides, add the word oxide after the name of the base, with locants. For example, C5H5N—O is named pyridine A-oxide or pyridine 1-oxide. 

The common method of naming aldehydes corresponds very closely to that of the related acids (see Carboxylic acids), in that the term aldehyde is added to the base name of the acid. For example, formaldehyde (qv) comes from formic acid, acetaldehyde (qv) from acetic acid, and butyraldehyde (qv) from butyric acid. If the compound contains more than two aldehyde groups, or is cycHc, the name is formed using carbaldehyde to indicate the functionaUty. The lUPAC system of aldehyde nomenclature drops the final e from the name of the parent acycHc hydrocarbon and adds al If two aldehyde functional groups are present, the suffix -dialis used. The prefix formjlis used with polyfunctional compounds. Examples of nomenclature types are shown in Table 1. 

A cyanohydrin is an organic compound that contains both a cyanide and a hydroxy group on an aUphatic section of the molecule. Cyanohydrias are usually a-hydroxy nitriles which are the products of base-cataly2ed addition of hydrogen cyanide to the carbonyl group of aldehydes and ketones. The lUPAC name for cyanohydrias is based on the a-hydroxy nitrile name. Common names of cyanohydrias are derived from the aldehyde or ketoae from which they are formed (Table 1). 

Two aldehydes (qv) have made their mark in the field of disinfection, namely formaldehyde [50-00-0] and glutaraldehyde [111-30-8]. Other aldehydes do not match these compounds in activity (111,112). 

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