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20220104090749.0 |
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880713s1987 xx a bm 000 0 eng d |
| 035 |
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|9 AAB3397AM
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|a (OCoLC)18207307
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| 035 |
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|a (OCoLC)ocm18207307
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|a TXA
|b eng
|c TXA
|d OCLCQ
|d OCLCF
|d OCLCO
|d OCLCQ
|d TXA
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| 049 |
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|a TXAM
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| 099 |
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|a 1987
|a Dissertation
|a B686
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| 100 |
1 |
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|a Bokser, Allan David.
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| 245 |
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|a Reaction mechanism of the buffer-catalyzed and substituted [beta]-cyclodextrin-catalyzed hydrolysis of catechol cyclic phosphates.
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| 264 |
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|c 1987.
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| 300 |
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|a xviii, 218 leaves :
|b illustrations ;
|c 29 cm
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| 336 |
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|a text
|b txt
|2 rdacontent
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| 337 |
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|a unmediated
|b n
|2 rdamedia
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| 338 |
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|a volume
|b nc
|2 rdacarrier
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| 500 |
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|a Typescript (photocopy).
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| 500 |
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|a Vita.
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| 502 |
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|b Ph. D. in Chemistry
|c Texas A & M University
|d 1987
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| 504 |
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|a Includes bibliographical references (leaves 194-200).
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|a The mechanism for the imidazole-catalyzed hydrolysis of catechol cyclic phosphate has been investigated. The Bronsted β-value obtained for the buffer-catalyzed hydrolyses at a 1:1 buffer ratio was 0.41. The Hammett φ-value obtained for the 1:1-[imidazole]: [imidazolium ion] buffer-catalyzed hydrolysis of substituted catechol cyclic phosphate was 1.08. The proton inventory plots for the imidazole-catalyzed hydrolysis of catechol cyclic phosphate at buffer ratios 75:25, 50:50, and 25:75 [imidazole]: [imidazolium] were dome-shaped, linear, and bowl-shaped, respectively. These different proton inventories indicate that the rate determining step of the reaction changes with the [imidazole]: [imidazolium] ratio and, thus, supports a stepwise mechanism for this reaction. An inverse solvent isotope effect for the hydroxide catalyzed hydrolysis of catechol cyclic phosphate (k(D₂O)/k(H₂O) = 1.63) and the decrease in the normal solvent isotope effects for the imidazole-catalyzed hydrolysis of 4-chlorocatechol cyclic phosphate and 4-nitrocatechol cyclic phosphate (k(H₂O)/k(D₂O) = 1.44, 1.83, respectively) further support this stepwise mechanism. Based on the ³¹P-NMR spectra for the β-cyclodextrin and substituted β-cyclodextrin-catalyzed hydrolysis of 4-tert butyl catechol cyclic phosphate, 6, the reaction occurs with inclusion of the 4-tert butyl catechol cyclic phosphate into the cavity of the cyclodextrin followed by the formation of the product. Heptakis-(2,6-dimethoxy)-β-cyclodextrin and heptakis-(2,3,6-trimethoxy)-β-cyclodextrin were poorer catalysts for the hydrolysis of 6 and 6-mono-imidazole β-cyclodextrin was a better catalyst for the hydrolysis of 6 than β-cyclodextrin. The solvent isotope effects, k(H₂O)/k(D₂O), for the β-cyclodextrin-catalyzed and the 6-mono-imidazole β-cyclodextrin-catalyzed hydrolyses of 6 were 1.35 and 2.35, respectively. Based on the proton inventory for the 6-mono-imidazole β-cyclodextrin-catalyzed hydrolysis of 6, the reaction mechanism is similar to that for the simple model study.
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| 650 |
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|a Bioorganic chemistry.
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| 650 |
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|a Catechol.
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| 650 |
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|a Cyclodextrins.
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| 650 |
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|a Enzymes.
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| 650 |
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4 |
|a Major chemistry.
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| 655 |
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7 |
|a Academic theses
|2 lcgft
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| 700 |
1 |
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|a Hogg, John L.,
|e degree supervisor.
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| 700 |
1 |
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|a Raushel, Frank M.,
|e degree committee member.
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| 700 |
1 |
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|a Sander, Eugene G.,
|e degree committee member.
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| 700 |
1 |
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|a Wong, Chi-Huey,
|e degree committee member.
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| 710 |
2 |
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|a Texas A & M University,
|e degree granting institution.
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| 856 |
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|u http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=754020041&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD
|z Link to ProQuest copy
|t 0
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| 856 |
4 |
1 |
|u https://hdl.handle.net/1969.1/DISSERTATIONS-26894
|z Link to OAKTrust copy
|t 0
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| 994 |
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|a C0
|b TXA
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|a Texas A&M University
|b J.J. Pickle Campus
|c High Density Repository
|s HDR
|d Remote Storage
|t 0
|e 1987 Dissertation B686
|h Other scheme
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|m A14839623777
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| 952 |
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|a Texas A&M University
|b College Station
|c Electronic Resources
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|e 1987 Dissertation B686
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|a 1987 Dissertation B686
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