HEM 109A Nomenclature of rganic ompounds - KEY 1. Name the following compounds. LAS a. 2,3-Dimethyl-pentane b. 5-sec-Butyl-5-isopropyl-2-methyl-nonane c. 4-Isopropyl-2,5-dimethyl-heptane l d. 1-hloro-2-methyl-4-propyl-cyclopentane e. yclobutyl-cyclohexane f. H 1-Methyl-cyclopentanol Br H g. 5-Bromo-hexan-3-ol Page 1 of 7
HEM 109A Nomenclature of rganic ompounds - KEY LAS H h. 2-Methyl-propan-1-ol -or- isobutyl alcohol N i. 3-aminohexane -or- 3-hexanamine -or- 1-Ethyl-butylamine N j. tert-butylamine -or- 2-amino-2-methylpropane -or- 2-methyl-2-propanamine 2. Draw the following compounds. a. 3-chloro-2,3-dimethylcyclopentanol H l 3-chloro-2,3-dimethylcyclopentanol b. 4,5-diethyl-3-iodo-4-octanamine I N 4,5-diethyl-3-iodo-4-octanamine c. sec-butyl chloride l sec-butyl chloride d. tert-butyl isobutyl ether tert-butyl isobutyl ether Page 2 of 7
HEM 109A Nomenclature of rganic ompounds - KEY e. neopentyl alcohol LAS H neopentyl alcohol f. dimethyl ether dimethyl ether g. ethane ethene h. methanal methanal i. ethanoic acid H ethanoic acid j. isobutyl amine N isobutylamine Additional Information: List of ommon Functional Groups on inside back cover of text or my website Steps for naming compounds 5 parts to a name Stereoisomerism Substituents Parent Hydrocarbon Unsaturation Functional Group Stereoisomerism indicates whether double bonds are cis/trans, E/Z and stereo centers (R, S). Will be covered in another handout. Substituents groups coming off of the parent hydrocarbon. Parent Hydrocarbon main/longest chain of carbons that includes functional groups > double bond(s) > triple bond(s) when appropriate. Unsaturation identifies any double or triple bonds -ane all single bonds -ene 1 or more double bonds -yne 1 or more triple bonds Functional Group functional group after which the compound is named. Page 3 of 7
HEM 109A Nomenclature of rganic ompounds - KEY Alkanes ( n n+2 ): ane, [Alkenes ( n n ): -ene, Alkynes ( n n-2 ): -yne later in 109A and beginning of 109B] 1. Determine the # of atoms in the longest continuous chain (parent chain) Watch for branches! Table 2.1 Nomenclature of Straight-hain Alkanes # of carbons Stem Name of alkane Molecular formula or skeletal structure of alkane 1 meth- 2 eth- 3 prop- 4 but- 5 pent- 6 hex- 7 hept- 8 oct- 9 non- 10 dec- 11 undec- 12 dodec- LAS 2. Number the chain in the direction that gives any substituent a lower number. (Numbers are not used in common names) a. If numbering in both directions gives the same number to a substituent, number in the direction that gives the lowest number to the alphabetically first substituent. Table 2.2 Names of ommon Alkyl Groups (same as previous Table 2.1, only ending has been changed to yl) Name hemical Formula Methyl H 3 Ethyl Propyl Isopropyl H 3 H 3 H 3 H Butyl H 3 H 3 H2 H 3 Isobutyl H 3 H Page 4 of 7
HEM 109A Nomenclature of rganic ompounds - KEY LAS sec-butyl H 3 H tert-butyl H 3 H 3 H 3 H 3 Pentyl H 3 H 3 Isopentyl Hexyl H 3 H 3 H H 3 Isohexyl H 3 H 3. Substituents are listed in alphabetical order, preceded by the # of the they are attached to. Prefixes, as well as sec and tert are ignored when alphabetizing, but iso and cyclo are NT. a. Numbers and words are separated by hyphens and numbers are separated by commas. b. Prefixes are used when there is more than one of the same substituent i. di, tri, tetra. 4. If there are two chains with the same number of s, choose the one with the most substituents as the parent chain. EX. 2,3-dimethylhexane 2,3-dimethylhexane 2,2,4-Trimethyl-hexane ycloalkanes: cyclo- -ane 1. Ring is parent unless the substituent has more s than the ring 2. If the ring has a. nly one substituent do NT number it (it will always be assumed to be on #1) b. Two substituents, cite them alphabetically and give the number 1 position to the first substituent. Page 5 of 7
HEM 109A Nomenclature of rganic ompounds - KEY LAS c. Three or more substituents, the substituent given the number 1 is the one that results in a second substituent getting as low a number as possible. i. If two substituents have the same low number, the ring is numbered in a direction that gives the third substituent the lowest possible number. EX. 1,1-dimethylcyclohexane 1-Ethyl-2-methyl-cyclopentane 1,1-Dimethyl-cyclohexane Alkyl Halides: -ide 1. Name of the alkyl group followed by the name of the halogen with ide ending. 2. Alkyl halides are named as substituent alkanes. The prefixes for the halogen end with o (fluoro, chloro, bromo, iodo). an be classified as 1 o, 2 o or 3 o (primary, secondary or tertiary) if the attached to the halide is attached to 1, 2 or 3 other s, respectively. EX. 2-fluoropropane F l l 2-Fluoro-propane isopropyl fluoride, 2 o 1-hloro-4-methyl-pentane isohexyl chloride, 1 o Table 2.2 Names of ommon Alkyl Groups (same as previous Table only ending has been changed to yl) Ethers: (R--R, R--R') oxy or ether ommon Name: 1. Name the two alkyl substituents in alphabetical order, followed by the word ether. Systematic Name: 2. Name the ether as an alkane with an R substituent (replace the yl ending with oxy). Page 6 of 7
HEM 109A Nomenclature of rganic ompounds - KEY LAS EX. ethoxy ethane 1-Isopropoxy-3-methyl-butane Ethoxy-ethane -or- diethyl ether -or- ethyl ether Alcohols: -ol ommon Name: 1. Name the alkyl group to which the H group is attached, followed by the word alcohol. Systematic Name: 2. Replace the e ending of the parent hydrocarbon with the suffix ol. l EX. 5-methyl-3-hexanol H H l 5-Methyl-hexan-3-ol -or- 5-methyl-3-hexanol H 4-hloro-cyclohexanol Amines: -amine ommon Name: 1. Name the alkyl groups bonded to the nitrogen in alphabetical order, followed by the word amine the entire name is written as one word. Systematic Name: 2. A number denotes the carbon to which the nitrogen is attached (can appear before the name, or before the amine ). 3. Replace the e ending of the parent hydrocarbon with the word amine. 4. Substituents whether attached to the nitrogen or to the parent hydrocarbon are listed in alphabetical order, and a number or and N is assigned to each one. EX. N N,N-dimethyl-3-pentamine N,N-diethyl-1-propamine or- diethylpropylamine N Page 7 of 7