Meth- prefix

The name of a carbon compound shows how many carbon atoms it contains, the type(s) of chemical bonds present between the carbon atoms, and the other atoms bonded to the carbon chain. The word methane, for example, shows that the compound has one carbon atom with only single bonds. All carbon compounds with one carbon atom begin with the prefix meth. In this case, the -ane ending shows that the compound contains only single bonds. All carbon compound names follow these rules. 

Aldehydes, acids, and esters have roots for one and two carbons that are usually form- and acet-, rather than meth- and eth-, because these prefixes had been used so long they were grandfathered into the naming system (formaldehyde and acetic acid, rather than methanal and ethanoic acid). Departures from IUPAC nomenclature often occur for very common substances and, fortunately, they rarely can be misunderstood (ethyl alcohol instead of ethanol). 

Now in the prefix meth- Figure 7.20 od of naming things the molecule in Figure 6.12 (p. 119) would he called isohexane because there are six carhon atoms total and it s the first rearrangement you can create heyond having all six carbons in a row. In the lUPAC system the molecule in Figure 6.12 is called 2-methylpentane. The... 

Owing to the numerous possibilities in which a 1,4-diene can be assembled, especially when heteroatoms are included, a nomenclature issue arises that needs to be addressed from the outset. According to the Hantzsch-Widman nomenclature system in combination with the lUPAC rules, hetera-di-ir-meth-ane reactions are those transformations in which a particular heteroatom replaces the caiixin atom of the 1,4-diene moiety the position is specified by means of a numerical prefix. We will use this suggested nomenclature for the di-Tr-methane photorearrangement as indicated for the substrates shown in Scheme 1. 

Any compound that has only one carbon atom in it has the prefix medi in its name. Any saturated hydrocarbon with a general formula C H2 +2 will have a name ending in ane. Hence CH3H would be meth... ane, or methane. 

The name of each of the members of the hydrocarbon classes has two parts. The first part, the prefix—meth-, eth-, prop-, but-, and so on—reflects the number of carbon atoms. When more than four carbons are present, the Greek or Latin number prefixes are used penP, hex-, kept-, oct-, non-, and dec-. The second part of the name, or the suffix, teUs the class of hydrocarbon. Alkanes have carbon-carbon single bonds, alkenes have carbon-carbon double bonds, and alkynes have carbon-carbon triple bonds and are indicated by the suffixes -ane, -ene, and -yne, respectively. 

First look at the first few letters of the name (meth, eth, prop, but, etc.). This is the prefix that tells the number of carbons in the parent chain. Next look at "an," "en," or "yn." These infixes indicate the nature of the carbon-carbon bonds in the parent chain.The letters that follow the infix are part of the suffix, which determines the class of compound to which the molecule belongs. 

The International Union of Pure and Applied Chemistry (lUPAC) method of naming alkanes is fairly simple. The names of all alkanes end in one. The prefixes, based on the number of carbons in the molecule, make naming a lot like counting. Meth- (1 carbon), eth- (2), prop- (3), but- (4), pent- (5), hex-(6), hep- (7), oct- (8), non- (9), and dec- (10) are the basic prefixes. If you know these, you will be able to breeze through naming. 

Latin word for a given number, but there are exceptions. A one-carbon unit has the prefix meth, two carbons are eth, three carbons are prop, four carbons are but, and five, six, seven, eight, nine, and ten carbons are derived from the Latin terms pent, hex, hept, oct, non, and dec, respectively. 

In this table, the carbon atom that serves as the point of attachment for the substituent to the main chain is shown in orange. The prefix for a C1-C20 substituent is meth->icos as in Table 4.1. Combining the yl suffix and the alkane prefixes indicates that a one-carbon substituent is methyl, a two-carbon substituent is ethyl, a three-carbon substituent is propyl, a four-carbon substituent is butyl, etc. 

Indicate the prefix that is used for the molecule (CH3)2CH(CH2)2CH20H meth, eth, prop, but, pent, or hex. 

To name a metal alkoxide, name the cation first, followed by the name of the anion. The name of the anion is derived from the prefix showing the number of carbon atoms and their arrangement meth-, eth-, isoprop-, tert-but-, and so on) followed by... 

In a strict sense, the prefix "iso" can only be applied to aldehydes showii meth. -brandui. It should be remembered that also odier internal aldehydes nmybe chiraL Ihis is an important reason why the description n/iso is more and more repbced by Hb. But both descriptions are useless when the ratio of two chiral centers has to be described. In diis situation, odier nomenclatures Imve to be applied, like a/p, syn/anti, or the Cahn—Ii old—Prelog (CIP) s tem. 

An alkyl group is an alkane from which an end hydrogen atom has been removed. If, on paper, we remove a hydrogen atom from methane, CH4, we get —CHj, where the dash indicates a bond that the alkyl is able to form with another atom. This —CH3 group, appearing in the structural formula of a compound, is called a methyl group. The term is made up of the prefix meth- for one carbon (Table 21.2) and the suffix -yl, which is applied to alky/ groups. If we compare two compounds. 

Produced synthetically, amphetamines (known as uppers ) are stimulants of the central nervous system much like epinephrine, but they also increase cardiovascular activity and depress the appetite. They are sometimes used to bring about weight loss, but they can cause chemical dependency. Methedrine is used to treat depression and in the illegal form is known as crank or crystal meth. The prefix meth means that there is one more CH3— group on the nitrogen atom. 

As mentioned already, alcohols are compounds that have a hydroxyl group (-OH) attached to a carbon atom. The most common alcohols are alkanes that have an oxygen atom inserted between one of the carbon atoms and a hydrogen atom. There are thousands, if not milUons, of alcohols. However, the alcohols people encounter most frequently are methanol, or methyl alcohol (CH3OH) ethanol, or ethyl alcohol (CHjCHjOH) and isopropyl alcohol (CjH OH). In fact, most people just use the word alcohol for any alcoholic beverage instead of the correct name, ethyl alcohol, but everyone knows what they mean. By the way, be sure to note the continued use of the prefixes meth, or methyl, for one carbon eth, or ethyl, for two carbons and prop, or propyl, for three carbons. 

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