Chapter 1 - Nomenclature Flashcards
What is the general formula for alkanes?
The general formula for alkanes is
CnH2n+2
where n is an integer
Name the first ten straight chain alkanes
- Methane: CH4
- Ethane: CH3CH3
- Propane: CH3CH2CH3
- Butane: CH3CH2CH2CH3
- Pentane: CH3CH2CH2CH2CH3
- Hexane: CH3(CH2)4CH3
- Heptane: CH3(CH2)5CH3
- Octane: CH3(CH2)6CH3
- Nonane: CH3(CH2)7CH3
- Decane: CH3(CH2)8CH3
What are the six steps to naming a compound?
- Find the highest priority functional group (most oxidized carbon) in the compound. This carbon receives the number 1, and the compund will end with the IUPAC suffix for this group, e.g. -oate for an ester or -al for an aldehyde.
- Find the longest continuous carbon chain attached to the highest priority functional group in the compound; numbering begins here, with the functional carbon receiving the number 1. If there are two or more chains of equal length, the most substituted chain gets priority.
- Number the chain so that the most substituents get the lowest number.
- Name the substituents. Carbon chain substituents are named according to their number root followed by -yl. These terms are places at the beginning of the compound, as prefix, followed by the name of the longest chain.
- Assign a number to each substituent. This applies even if the prefixes di-, tri- or tetra- are used.
- Complete the name. Begin with the substituents, listed in alphabetical order; with each substituent name preceeded by its assigned number.
Name the substituent:
t-butyl
Name the substituent:
neopentyl
Name the substituent:
isopropyl
Name the substituent:
sec-butyl
Name the substituent:
isobutyl
General formula for cycloalkanes:
The general formula for cycloalkanes is
CnH2n
where n is an integer. For every ring in the structure there will be two fewer hydrogens than in the straight-chain counterpart. Cycloalkanes have one degree of unsaturation (two fewer H than straight chain) for each ring.
How are ring structures named?
Cycloalkanes are named by the number of carbon atoms in the cyclo-. The ring is numbered starting at the point of greatest substitution, with substituents receiving the lowest possible numbers.
How is functional group priority determined?
Priority is based on the oxidation state of the functional group’s carbon. Oxidation is the loss of electrons (LEO), and so the most electropositive carbon will be the highest priority. Generally, however, the carbon with the most bonds to oxygen tends to be the most oxidized.
Ethylene: formula and structure
The smallest alkene: CH2CH2
Propylene: Formula and structure
CH2CHCH3
General formula for an alkene
The general formula for alkenes is
CnH2n
where n is an integer. For every double bond in the structure there will be two fewer hydrogens than in the straight-chain counterpart. Alkenes have one degree of unsaturation (two fewer H than straight chain) for each double bond.
Name the following alkanes:
- n-hexane
- 3-methylpentane
- 2-methylpentane
- 2,2-dimethylbutane
- 2,3-dimethylbutane
Vynil derivatives
Monosubstituted ethylenes (ethenyl-), such as chloroethene (vynil chloride) below. Vynil derivatives have a substituent group attached to the double-bonded carbon.
Allyl derivatives
A substituent with the structural formula H2C=CH-CH2-R, where R is the rest of the molecule. It consists of a methylene bridge (-CH2-) attached to a vinyl group (-CH=CH2). 3-bromo-1-propene (allyl bromide) is an example.
Name the following compound
2-propen-1-ol (allyl-alcohol)
Name the following compound. What is interesting about this molecule?
Ethenol (vynil alcohol). Vynil alcohols are unstabel and exist in equilibrium with their aldehyde counterparts: under normal conditions, ethenol converts (tautomerizes) to acetaldehyde.
Methylene
A methylene group is any part of a molecule that consists of two hydrogenatoms bound to a carbon atom, which is connected to the remainder of the molecule by a double bond. Methylene cyclohexanse, below, is an example.
If there is a tie when assigning priority in a molecule with double and triple bonds, which takes precedence?
The double bond
Cycloalkenes
Rings containing one or more double bonds. These are named like cycloalkanes, but with the suffix –cyclo(x)ene rather than –cyclo(x)ane. If there is only one double bond and no other substituents the ring does not have to be numbered, e.g. cyclohexene:
Name the following compound.
trans-4-methylcyclooctene
cis and trans configurations of alkenes
Alkynes
Compounds with at least one carbon-carbon triple bond. Alkynes have the suffix **-yne **and adhere to the general formula CnH2n-2. An alkyne has two degrees of unsaturation because it has two pi bonds. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2(IUPAC, ethyne)
Name the following compound
Acetylene (IUPAC, ethyne)
Name the following compound
4-methylhex-2-yne
Name the following compound
Cyclodecyne
When there are both double and triple bonds in an alkyne, how does one name the compound?
The molecule’s name will end in “y-root-en-x-yne,” where the first number y describes the position of the double bond, the second number x describes the position of the triple bond, and *root *is the prefix representing the length of the principle carbon chain.These numbers are chosen to give the sum of x and y the smallest possible value, and the double bond is given the lowest number.
Haloalkanes
Alkanes that contain a halogen (F, Cl, Br, or I) substituent. These are commonly called alkyl halides. Chloroethane (ethyl chloride) is an example
How are haloalkanes named?
Alkyl halides do not receive a special suffix and instead use that of the alkane group (-ane). The backbone chain should be numbererd so that the substituents have the lowest numbers possible, however, with the halide taking precedence over alkyl groups, e.g 1-chloro-2-methylcyclohexane below:
How are alcohols named according to the IUPAC system?
In the IUPAC system, alcohols are named by replacing the -e of the corresponding alkane with -ol, and the chain is numbered so that the hydroxyl (-OH) group receives the lowest number possible. alcohols take precedence over alkenes and alkynes.
Name the following compound
hept-6-en-1-ol
What are the common names and formulas for the following simple alcohols
- 1-propanol
- 2-propanol
- 2-butanol
- 2-methyl-1-propanol
- 2-methyl-2-propanol
- 1-propanol: n-propyl alcohol CH3CH2CH2OH
- 2-propanol: isopropyl alcohol (CH3)2CHOH
- 2-butanol: sec-butyl alcohol (CH3)CH(OH)CH2CH3
- 2-methyl-1-propanol: isobutyl alcohol (CH3)2CHCH2OH
- 2-methyl-2-propanol: t-butyl alcohol (CH3)3COH
Diols
AKA glycols. Molecules with two hydroxyl groups, such as Propane-1,3-diol:
HO-CH2CH2CH2OH
vicinal and geminal diols
- Vicinal diols: compounds with hydroxyl groups on adjacent carbons
- Geminal diols (hydrates): compounds with hydroxyl groups on the same carbon
Ethers
a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R
Ether IUPAC naming system
In the IUPAC nomenclature system, ethers are named using the general formula “alkoxyalkane”, for example
CH3CH2OCH3
is methoxyethane. The simpler alkyl radical is written in front, so CH3OCH2CH3 would be methoxy (CH3O) ethane (CH2CH3). as substituents ethers go by the (alk)oxy designation, e.g. ROCH3 would be a “methoxy-“ group.
Ethers: common name system
Common names for ethers are derived by naming the two alkyl groups in alphabetical order, followed by the word ether, e.g. ethyl methyl ether (methoxyethane):
CH3CH2OCH3
Cyclic ethers: naming conventions
numbering of the ring begins at the oxygen and proceeds to provide the lowest numbers for the substituents. Three membered rings are called oxiranes by IUPAC, but they are olmost always referred to by their common name, epoxides.
Tetrahydrofuran (THF): structure
Name the following compound
Oxirane (ethylene oxide)
1-isopropoxyhexane: structure and common name
n-hexyl isopropyl ether
Aldehyde: structure and naming convention
Terminal carbonyl. Always receives the number 1 if it is highest priority. named by replacing -e from the parent alkane with -al. As a substituent aldehydes are named with the prefix oxo-.
Formaldehyde (structure)
Also known by the IUPAC name methanal, this is the simplest aldehyde.
acetaldehyde (strucure)
Name the following compound
commonly known as propionaldehyde (IUPAC propanal)
Acetone
The simplest ketone
Ketone: structure and naming convention
Ketones feature a carbonyl group (C=O) bonded to two other carbon atoms. They are named with the suffix -one instead of the -e of the parent alkane. As a substituent ketones are named with the prefix oxo-. The common name for ketones is derived by listing the alkyl groups in alphabetical order followed by the word ketone, e.g. methyl vinyl ketone (IUPAC 3-butene-2-one):
Name the following compound:
5-chloro-2-pentanone
Name the following compound:
3-(5-oxohexyl)cyclohexanone
alpha (beta, etc.) carbons: naming system
Alternative numeric designation used for carbonyl compounds that names all of the carbons relative to the carbonyl group. The carbon adjacent to the carbonyl carbon is the alpha carbon, with successive carbons receiving higher letters of the greek alphabet (beta, gamme, etc.)
Carboxylic acids
An organic compound that contains the terminal carboxyl group (COOH), and bearing the general formula R-COOH. Carboxylic acids are the highest priority functional group, do every other functional group on the compound will be named as a substituent. The IUPAC suffix is -oic acid, while the prefix is carboxy-.
Formic acid (structure)
This is the simplest carboxylic acid, and is referred to almost exclusively by its common name.
(IUPAC is methanoic acid)
Name the following compound
acetic acid
This compound goes almost exclusively by its common name (IUPAC name is ethanoic acid).
Name the following compound
propionic acid.
This compound goes almost exclusively by its common name (IUPAC name is propanoic acid).
Amine
Functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. They have the suffix -amine and the prefix amino-. Amines may be primary, secondary, or teritiary, with the prefix N- showing substitution on the nitrogen atom.
aminopentan-2-amine (structure)
Name the following structure
2-ethyl-N-methylpentan-1-amine
heptan-4-amine (strucure)
2-aminoheptanoic acid (strucure)
Anhydride
An organic compound that has two acyl groups bound to the same oxygen atom. Symmetrical anhydrides are named by replacing the word acid in the name of the parent carboxylic acid by the word anhydride. Thus, (CH3CO)2O is called acetic anhydride. Mixed (or unsymmetrical) anhydrides, such as acetic formic anhydride, are also known.
Ester
chemical compounds consisting of a carbonyl adjacent to an ether linkage. The IUPAC suffix for esters is -oate, while the prefix is alkoxycarbonyl-.
Amide
An amine functional group adjacent to a carbonyl. Prefix amido-, suffix -amide
Nitrile/Cyanide
Nitriles are named witht he cyano- prefix and the -nitrile suffx
4-ethyl-1,2-dimethylcyclohexane
cis-1-ethoxy-2-methoxycyclopentane
