Chain attached to a ring

Reactivity of the Side Chain Attached to a Ring Carbon 661... 

The mass spectrometric behavior of alkylated pyrazines resembles that of a-alkyl-substituted pyridines, which also have the side chain attached to a ring carbon adjacent to a nitrogen (Biemann,10 pp. 184, 132 Biemann in12, p. 534). A prominent cleavage reaction in such compounds occurs at a C-2—C-3 bond in the side chain (cf. (65)- -[66]), probably because the positive charge at C-2 of the chain is stabilized in the same manner as in [68a]. 

A further interesting polyazamacrocycle (67) carrying a functional group in the side chain attached to a ring carbon atom has been synthesized using the tosylate method (Equation (27)) <88HCA602>. 

The shorter form implies no additional carbon atoms, and is used when the group is part of a chain. The long form implies one more carbon atom than the parent stmcture, and is used when the group is attached to a ring, or for other reasons is not conveniently named as part of a carbon skeleton. 

Prostaglandin F, a hormone that causes uterine contraction during childbirth, has the following structure. Are the two hydroxyl groups (-OH) on the cyclopentane ring cis or trans to each other What about the two carbon chains attached to the ring ... 

Note This method is used for assemblies of non-identical systems also it is sometimes preferable to that of Rule A-55 for assemblies of identical systems when a group to be specified as a suffix or as a separate word is present in a chain attached to the ring assembly. 

Exercise 5-6 Examine the structures of /3-carotene and vitamin A shown on p. 33 and p. 50 and determine the configuration at each of the double bonds in the chain attached to the ring(s). Are these substances chiral or achiral ... 

Next consider the synthesis of M from readily available starting materials. The relevant facts about M are that (a) it contains an aromatic ring, an acetate ester, and a vinyl group (b) it has a straight chain attached to the ring and (c) all the functional groups are isolated. 

Functional groups on the aliphatic side-chains attached to aromatic rings behave in a manner typical of aliphatic compounds. 

Remember that the principal chain must contain the aldehyde or ketone group and that an aldehyde group occurs only at the end of a chain. The aldehyde carbon is carbon 1 in an acyclic compound, and the suffix -carbaldehyde is used when the aldehyde group is attached to a ring. 

The suffixes -oic acid, -oyl halide, -amide, -nitrile, and -al are used when the functional group is at the end of a carbon chain, as in pentanoic acid. The endings -carboxylic acid, etc., are used when the group is attached to a ring, as in 2-pyridinecarboxylic acid. 

Hydroxymethyl -CH -OH), when attached to a ring or onto the side of a chain. Hydroxymethyl was found to be inactive at 300 C, when it formed the end of a straight unbranched molecule (or polymer chain), but its activity increases strongly with increasing temperature. 

The carboxylic group attached to a ring or a side-chain carbon atom in the... 

Several reagents can effect dehydrochlorination from an alkyl side chain attached to a cyclopropane ring. Thus, for example, short heating of equivalent amounts of (1,1-di-chloroethyl)cyclopropane (1) and quinoline gave an 80% yield of (l-chloroethenyl)cyclo-propane (2) no isomeric ethylidenecyclopropane was reported. 

Carboxylic acids are almost always named using a suffix. The suffix oic acid is attached to the name for the longest continuous carbon chain. If the acid group is attached to a ring the suffix carboxylic acid is used. 

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