IUPAC Nomenclature Chem12A, Organic Chemistry I

Transcription

1 IUPAC Nomenclature ChemA, rganic Chemistry I IUPAC PEFIXES Prefix Substituent Group Number of Carbons meth- methyl eth- ethyl prop- propyl but- butyl pent- pentyl hex- hexyl hept- heptyl 7 oct- octyl 8 non- nonyl 9 dec- decyl 0 ISMES F SUBSTITUENT GUPS Name Formula Structure -n-propyl -- CH7 -isopropyl -- CH7 -n-butyl -- CH9 -isobutyl -- CH9 -sec-butyl -tert-butyl -- CH9 -- CH9

2 Primary, : attached to only one other carbon Secondary, : attached to two other carbons Tertiary, : attached to three other carbons F ALKANES:.) Find the longest chain of connected carbon atoms this is your base chain. The number of carbons in the chain determines the prefix for the name. prefix + ane (i.e., carbons but + ane, butane).) Number so that the lowest possible number is on the substituent encountered first. -methylbutane NT -methylbutane.) If both substituents can be equally low, give the lowest number to the substituent that comes first alphabetically ethyl--methylheptane NT -ethyl--methylheptane The prefixes sec- and tert- do not count for alphabetical order, but iso- does..) Name each substituent. The number of carbons included in the substituent (only carbons not a part of the base chain) determines the prefix for the name. # - prefix + yl,-dimethylpentane If substituents are repeated, include the number of each substituent s location and add a numerical prefix before its name. #,#-numerical prefix + prefix+yl

3 .) Add substituents before the base chain name in alphabetical order. Add hyphens between all but the last substituent and no spaces. #-substituent + base chain #-substituent-#-substituent + base chain F CYCLALKANES:.) The ring will always be your base chain of carbons. The number of carbons in the ring determines the prefix for the name. Indicate the cyclic structure by adding a cyclo- prefix before the carbon prefix and the single bonds by adding a -ane suffix after the carbon prefix. cyclo+prefix+ane (i.e., carbons in a ring cyclo+pent+ane, cyclopentane).) Number so that the starts on the substituent encountered first. -methylcyclopropane (methylcyclopropane) NT -methylcyclopropane.) For two or more substituents, number so that the smallest possible range can be given.,-dimethylcyclopentane NT,-dimethylcyclopentane.) Priority for numbering substituents follows the same rules as alkanes..) Naming for substituents follows the same rules as alkanes..) Naming the overall compound follows the same basic rules as alkanes, but must include cis-trans isomerization if it is present. If there is only one substituent in the position, the number can be dropped. #-substituent + base chain #-substituent-#-substituent + base chain For two substitutients, cis-trans isomerization may present. Prefixes of cis- (for both substituents pointing up or both pointing down) or trans- (for one substituent pointing up and the other pointing down) must be used.

4 cis trans cis-,-dimethylcyclopentane trans-,-dimethylcyclopentane cis/trans-#-substituent-#-substituent + base chain F ALKENES:.) Find the longest chain of connected carbon atoms that contains all carbons that form the double bonds this is your base chain..) Indicate the number of double bonds present by adding a numerical prefix before the ene suffix; retain the ending vowel on the carbon prefix if a numerical prefix is used. prefix+numerical prefix+ene (i.e., carbons + double bonds buta+di+ene, butadiene).) Number so that the lowest possible number is on the first encountered double bond. -methyl--butene NT -methyl--butene.) Indicate the position of the double bond with its position before the base chain name. If there is only one double bond present in the position, it can be dropped. #-prefix+numerical prefix+ene (i.e., carbons + double bond on the position -butene or butene).) If two double bonds can be equally low, number the substituent the lowest possible. -ethyl-,-butadiene NT -ethyl-,-butadiene.) Priority for numbering substituents follows the same rules as alkanes.

5 -ethyl--methyl-,-pentadiene NT -ethyl--methyl-,-pentadiene 7.) Naming substituents follows the same rules as alkanes. 8.) Naming the overall compound follows the same basic rules as alkanes, but must include cis-trans E/Z isomerization if it is present. If both carbons in the C=C have one H attached, use cis- (both H s pointing up or both down) or trans- (one H pointing up and one down) prefixes. cis/trans-#-substituent-#-substituent-#-base chain+ene cis trans cis--butene trans--butene If each C in the C=C is attached to two different substituents, use E (one higher priority is pointing up and the other down) or Z (both higher priority are pointing up or both down) Z-isomer (Z)-,-dimethyl-,-hexene E-isomer (E)-,-dimethyl-,-hexene F ALKYNES:.) Follow the same rules for nomenclature as alkenes, but include a -yne suffix. #-substituent-#-base chain+yne #-substituent-#-substituent-#-base chain+yne F CYCLALKENES:.) Follow the same rules for nomenclature as cycloalkanes, but different numbering..) Number so that the lowest numbers are on the carbons involved in the double bonds.

6 -methylcyclohexene NT -methyl--cyclohexene..) rder the numbers so that the double bonds extend for the smallest possible range.,-cyclohexadiene NT,-cyclohexadiene.) If all carbons in the double bonds can be equally low, give the lowest possible number to the substituent encountered first. -methylcyclopentene NT -methylcyclopentene.) Priority and naming for substituents follows the same rules as alkanes..) Naming overall compounds follows the same rules as alkenes, but a cyclo- is added. #-substituent-cyclo+base chain+ene #-substituent-#-substituent-+cyclo+base chain+ene F BENZENE AS A SUBSTITUENT:.) Name any benzene substituent on any larger chain (CH- group) as phenyl-. F BENZENE DEIVATIVES:.) Find the aromatic benzene ring this is your base chain..) For monosubstituted benzene derivatives, the position is given to the substituent, but can be dropped from the name.

7 Br -bromo-benzene or bromobenzene.) Four special monosubstituted benzene derivatives always take priority. They are always numbered as the position and retain their common names, which replace benzene in the base chain name. NH H H toluene aniline phenol benzoic acid.) For disubstituted or trisubstituted benzene derivatives, number in such a way to assign the lowest possible range for the two substituents. Br Br Br Br Br,-dibromobenzene NT,-dibromobenzene -bromotoluene For disubstitued benzene derivatives, prefixes can stand in for numbering. For,-, the prefix ortho- or o- can be substituted. For,-, the prefix meta- or m- can be substituted. For,- the prefix para- or p- can be substituted. ortho- (o-) meta- (m-) para- (p-) ortho-dimethylbenzene meta-dimethylbenzene para-dimethylbenzene o-dimethylbenzene m-dimethylbenzene p-dimethylbenzene,-dimethylbenzene,-dimethylbenzene,-dimethylbenzene

8 .) Naming the overall compound follows the same basic rules as alkanes. If there is no special substituent, then name substituents in alphabetical order. If there is a special substituent, name the non-special substituents first in alphabetic order, then replace benzene with the name of the special substituent. #-substituent- special name #-substituent-#-substituent- special name F FUNCTINAL GUPS: Functional Group Formula Suffix carboxylic acid H -oic acid acid anhydride ester acid chloride amide Cl N -oic anhydride -oate -oyl chloride -amide nitrile N -nitrile aldehyde ketone H -al (common: aldehyde) -one alcohol H -ol thiol SH -thiol

9 amine N alkene -amine -ene alkyne -yne ether -oxy- (common: ether) alkyl halide X F = fluoro-, Cl = chloro, Br = bromo, I = iodo F FUNCTINAL GUPS:.) Find the longest chain of connected carbon atoms that contains all carbons/atoms directly bonded to/starting the functional group highest in priority. H H -propyl-,-ethanediol The base chain must contain all carbons that directly bonded to any alcoholic group. Indicate the number of alcoholic groups present by adding a numerical prefix before the ol suffix; retain the ending vowel on the first prefix if a numerical prefix is used. prefix+numerical prefix+ol.) Number so that the lowest possible number is on the first encountered functional group. H H -propanol or propanol NT -propanol.) Indicate the position of the alcohol with its number before the base chain name.

10 If there is only one alcohol present and it resides in the position, the number can be dropped from the name and understood. #-prefix+numerical prefix+ol.) If two functional groups can be equally low, give the lowest number possible to the substituent encountered first. H H H H -ethyl-,-butanediol NT -ethyl-,-butanediol.) Naming the overall compound follows the same rules as alkanes. #-substituent-#-base chain (i.e., -ethylbutanol) #-substituent-#-substituent-#-base chain (i.e., -ethyl-,-dimethyl--pentanol)