Condensed Structures of alkanes e can represent an alkane in a brier form or in many types of extended form a condensed structure does not show bonds but lists atoms. such as CH3 CH2CH3(propane) CH3(CH3)2CCH3 (2, 2-dimethylpropane
Condensed Structures of Alkanes • We can represent an alkane in a brief form or in many types of extended form • A condensed structure does not show bonds but lists atoms, such as CH3CH2CH3 (propane) CH3 (CH3 )2CCH3 (2,2-dimethylpropane)
p30 Alkyl group-remove one h from an alkane (a part of a structure General abbreviation"R(for radical, an incomplete species or the"rest of the molecule) Name: replace -ane ending of alkane with ending CH, is "methyl"(from methane) =CH_CH3 is"ethyl"(from ethane) See table 2. 4 for a list
• Alkyl group – remove one H from an alkane (a part of a structure) • General abbreviation “R” (for Radical, an incomplete species or the “rest” of the molecule) • Name: replace -ane ending of alkane with -yl ending ⺷CH3 is “methyl” (from methane) ⺷CH2CH3 is “ethyl” (from ethane) • See Table 2. 4 for a list p.30
Types of Alkyl groups Classified by the connection site(See Figure 2.3) a carbon at the end of a chain [primary(a)alkyl group a carbon in the middle of a chain [secondary(1 alkyl groupl a carbon with three carbons attached to it [tertiary (叔) alkyl group] H R-C—H R-C-H R-C-H R-C-R R R Primary carbon (1y Secondary carbon(2) Tertiary carbon (3) quaternary carbon(4) is bonded to one is bonded to two is bonded to three is bonded to four other carbon other carbons other carbons other carbons
Types of Alkyl groups Classified by the connection site (See Figure 2.3) – a carbon at the end of a chain [primary(伯) alkyl group] – a carbon in the middle of a chain [secondary(仲) alkyl group] – a carbon with three carbons attached to it [tertiary (叔) alkyl group]
p28 Bu Prl. Bul Bu CH3CHCH3 CH3CHCHCH3 CHCHCH CH C-Cik isopropyl sec-butyl isobutyl Ch tert-butyl 异丙基 仲丁基 异丁基 叔丁基 CH CH3CHCH2CH CH3 CH3-C-CH3 isopentyl(amyl) Ch neopentyl CH,CH tert-pentyl 异戊基 新戊基 叔戊基
CH3CHCH3 CH3CH2CHCH3 CH3CHCH2 CH3 CH3 C CH3 CH2CH3 CH3CHCH2CH2 CH3 CH3 C CH3 CH3 CH2 isopropyl 异丙基 sec-butyl 仲丁基 isobutyl 异丁基 tert-butyl 叔丁基 isopentyl(amyl) 异戊基 neopentyl 新戊基 tert-pentyl 叔戊基 CH3 C CH3 CH3 p.28 Pri - Bui - But Pri - - iPr- tBu-
2.3 Naming Branched-Chain 30 Alkanes Compounds are given systematic names by a process that uses Prefix-Parent-Suftix Follows specific rules Named as longest possible chain Carbons in that chain are numbered in sequence substituents are numbered at their point of attachment Compound name is one word( German style Complex substituents are named as compounds would See specific examples in text
2.3 Naming Branched-Chain Alkanes • Compounds are given systematic names by a process that uses – Prefix-Parent-Suffix • Follows specific rules – Named as longest possible chain – Carbons in that chain are numbered in sequence – substituents are numbered at their point of attachment – Compound name is one word (German style) – Complex substituents are named as compounds would be • See specific examples in text p.30