Formation and reactions of ipso adducts from chlorination of 2-methyl-2-aryloxypropanoic acids
| dc.contributor.author | Ji, Ruizhi | |
| dc.contributor.supervisor | Fischer, Alfred | |
| dc.date.accessioned | 2018-06-21T00:17:24Z | |
| dc.date.available | 2018-06-21T00:17:24Z | |
| dc.date.copyright | 1990 | en_US |
| dc.date.issued | 2018-06-20 | |
| dc.degree.department | Department of Chemistry | |
| dc.degree.level | Doctor of Philosophy Ph.D. | en_US |
| dc.description.abstract | Chlorination of 2-methyl-2-aryloxypropanoic acids with aqueous hypochlorous acid gives spiro chloro adducts in moderate to high yields. In chlorination of 2-methyl-2-(2-methylphenoxy)propanoic acids, 1,2-adducts are formed, while in the case of 2-methyl-2-(4-methylphenoxy)propanoic acids, 1,4-adducts are obtained. In addition to the spiro adducts, 2-methyl-2-(4-chlorophenoxy)propanoic acids in the former case, and 2-methyl-2-(2-chlorophenoxy)propanoic acids in the latter case are formed, respectively. No 6-chlorosubstituted products are detected on chlorination of any of the substrates. Chlorination of 2-methyl-2-(2,4-dimethylphenoxy)propanoic acid affords only the 1,4-adduct. However, chlorination of 2-methyl-2-(5-chloro-2,4-dimethylphenoxy)propanoic acid gives both the 1,2- and the 1,4-adduct. 2-Methyl-2-(3,5-di-t-butylphenoxyl)propanoic acid on chlorination yields the diastereomeric secondary chloro adduct, 8-chloro-7,9-di-t-butyl-3,3-dimethyl-1,4-dioxaspiro (4,5) deca-6,9-dien-2-one. Under neutral and non-polar conditions, most of the 1,2-adducts undergo a thermal rearrangement of the chlorine which is shown to be a (1,5) sigmatropic chlorine shift. The rearrangement rates are highly dependent on the nature of the substituents in the diene systems. Under acidic and non-nucleophilic conditions, most of the 1,4-adducts undergo an intramolecular 1,2 chlorine shift followed by aromatization to give the 3-chloro-substituted products. For the dienes in which the 3-position is originally substituted, successive 1,2 chlorine migrations and/or side chain substitution are observed. On the other hand, the 1,2-adducts under similar reaction conditions undergo an intermolecular 1,4 chlorine shift to give the 5-chlorosubstituted products. In the case that the 5-position is substituted by a methyl group, side chain substitution at the 5-methyl takes place. In the presence of added base, solvolyses of the 1,4-adducts in methanol affords simple solvolysis products and/or 1,2 carboxyl rearranged products. The kinetic studies of the solvolyses of the 1,4-adducts have been carried out. The results reveal the substituent effects on both the simple solvolysis displacement and the rearrangement reactions. | en_US |
| dc.description.scholarlevel | Graduate | en_US |
| dc.identifier.uri | http://hdl.handle.net/1828/9486 | |
| dc.language | English | eng |
| dc.language.iso | en | en_US |
| dc.rights | Available to the World Wide Web | en_US |
| dc.subject | Organochlorine compounds | en_US |
| dc.subject | Chlorine compounds | en_US |
| dc.subject | Aromatic compounds | en_US |
| dc.subject | Reactivity | en_US |
| dc.title | Formation and reactions of ipso adducts from chlorination of 2-methyl-2-aryloxypropanoic acids | en_US |
| dc.type | Thesis | en_US |