Organic Functional Groups - Organic Chemistry

A secondary amine is an amine (nitrogen atom) that is attached to two carbon-containing groups (alkyl groups or aryl groups). The nitrogen in ephedrine is attached to two alkyl groups, making it a secondary amine.

Primary amines are generally written as . Secondary amines are generally written as . A tertiary amine will be bound to three different R-groups. Quaternary amines require a positive charge on the nitrogen atom to accommodate a fourth R-group.

An amino group is a nitrogen-containing functional group, and is the part pictured on the right of the given molecule. This amine has three substituents: the alkyl ketone, the methyl, and the ethyl. Hydrogens do not count as "substituents." Any amine with three substituents is considered a "tertiary" amine.

This amine is chiral because it has four different substitutions at the nitrogen atom, which is the definition of chirality.

Note: "tetriary" is not a real term in organic chemistry.

A tertiary amine has three organic groups bonded to it. Triethylamine has three ethyl groups bonded to it, so that is the correct answer. Ammonia is , so it has no organic groups attached. Piperidine is a six-membered ring with a nitrogen as one of the members, making it a secondary amine. Aniline is a benzene ring with a bonded to it, so it is a primary amine.

C is the correct answer.

The molecule pictured above is an anime because it contains a nitrogen group bonded to two hydrogen atoms and one R-group. A shows an aldehyde, B shows an amide, and D shows a carboxylic acid.

A molecule is anti-aromatic when it follows all of the criteria for an aromatic compound, except for the fact that it has pi electrons rather than pi electrons, as in this case.

A molecule is aromatic when it adheres to 4 main criteria:

1. The molecule must be planar

2. The molecule must be cyclic

3. Every atom in the aromatic ring must have a p orbital

4. The ring must contain pi electrons

The carbon on the left side of this molecule is an sp3 carbon, and therefore lacks an unhybridized p orbital. The molecule is non-aromatic.

Ketones are carbonyls with two R-groups attached the the carbonyl carbon.

This is an acid halide, were X is any halogen (group VII). They are the most reactive of all the carboxylic acid derivatives.

Carboxylic acids are composed of one R goup and a hydroxy group bound to the carbonyl carbon. The hydroxyl group gives the molecule acidic properties.

This is a hemiketal. Hemiketals are formed from the reaction of a ketone with an alcohol. The alcohol attacks the carbonyl carbon, reducing the double bond and adding a hydroxyl group.

Ketals have two -OR groups bound to a central carbon. The R groups attached to the oxygens are not necessarily the same. Ketals result from the reaction of a ketone with two equivalents of alcohol.

Acid anhydrides are relatively reactive, since they have a fairly good leaving group (the conjugate base of a carboxylic acid) \[COO-\]. They are formed by reacting two carboxylic acids via dehydration synthesis.

This is an amide. It is very unreactive since its leaving group is the conjugate base of an amine \[HNR-\].

Esters are relatively unreactive since the leaving group is an alkoxide ion (OR-), which is the conjugate base of an alcohol (a relatively weak acid).

The correct answer is D.

The molecule pictured above is an aldehyde because it contains an oxygen double bonded to the last carbon on the carbon chain. A contains a amide group, B contains a ketone, and C contains a carboxylic acid group.

In this question, we're shown the structure of the nucleoside called guanosine. We're asked to determine how many amide functional groups exist in this molecule.

First, to answer this question, we need to know what an amide functional group is. Amides consist of a carbon atom double bonded to an oxygen atom, and single bonded to a nitrogen atom. Note that this is distinct from the similarly named amine functional group, which contains a nitrogen atom with a lone pair of electrons and single bonded to three other atoms, which can be hydrogen or "R-groups" containing carbon atoms.

When looking at the molecular structure of guanosine, we can see that there is only a single amide group.

For this question, we're being asked to identify a characteristic of ammonia.

First, we need to remember what ammonia is. Ammonia is a molecule that consists of a nitrogen atom bonded to three separate hydrogen atoms. In doing so, these three bonds contribute to six of the valence shell electrons for nitrogen. The remaining two valence electrons exists on the nitrogen atom as a lone pair. Thus, there is only one lone pair of electrons (pair being two).

Also, the lone pair of electrons on ammonia allows it to act as a Lewis base by donating them (not a Lewis acid, which accepts electrons). Furthermore, this tendency for ammonia to donate its electrons would make it a nucleophile, not an electrophile.

The molecule's longest carbon chain has 3 carbons (thus, "prop"), and the lack of double bonds makes it an alkANe (thus "propan-"). The only functional group on this molecule is the amino group (thus "propanamine"), located on carbon number 1 if read from right to left, or carbon number 3 if read from left to right. The IUPAC rules state that the correct name for a molecule numbers the carbon chain such that functional groups get the lowest numbers possible. Thus "1-propanamine."

For a compound to be considered aromatic, it must be flat, cyclic, and conjugated and it must obey Huckel's rule. Huckel's rule states that an aromatic compound must have pi electrons in the overlapping p orbitals in order to be aromatic (n in this formula represents any integer). Only compounds with 2, 6, 10, 14, . . . pi electrons can be considered aromatic. Compound A has 6 pi electrons, compound B has 4, and compound C has 8. This eliminates answers B and C. Answer D is not cyclic, and therefore cannot be aromatic. The only aromatic compound is answer choice A, which you should recognize as benzene.

The correct answer is (8) Annulene. This is because all aromatic compounds must follow Huckel's Rule, which is 4n+2. Note that "n" in Huckel's Rule just refers to any whole number, and 4n+2 should result in the number of pi electrons an aromatic compound should have. For example, 4(0)+2 gives a two-pi-electron aromatic compound.

It is also important to note that Huckel's Rule is just one of three main rules in identifying an aromatic compound. An annulene is a system of conjugated monocyclic hydrocarbons. A compound is considered anti-aromatic if it follows the first two rules for aromaticity (1. Pi bonds are in a cyclic structure and 2. The structure must be planar), but does not follow the third rule, which is Huckel's Rule.

(8) Annulene follows the first two rules, but not Huckel's Rule, and is therefore antiaromatic; no value of a whole number for "n" will result in 8 with the formula 4n+2.