Studies of Some beta-Propanolamines, Imidazo [2,1-b] Thiazoles and Ylides, by X-Ray Analysis

Cameron, Ian R (1975) Studies of Some beta-Propanolamines, Imidazo [2,1-b] Thiazoles and Ylides, by X-Ray Analysis. PhD thesis, University of Glasgow.

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In this thesis, single crystal X-ray diffraction techniques have been used to determine the crystal and molecular structures of ten compounds. The contents are presented in four Parts, the first of which is a brief discussion on some theoretical aspects of these techniques, with special emphasis being placed on the Direct Methods of structure determination used predominantly in this research. In Part 2, X-ray analysis has been used to study the molecular structures and conformations of five similar compounds of interest in the treatment of certain heart disorders. In particular, the compound Inderal (1-(2-Hydroxy-3-isopropylamino-propoxy)-naphthalene) is used extensively as a beta-adrenergic receptor blocking agent, and in order to investigate possible characteristic conformational differences and/or similarities between active and inactive beta-blocking agents and their relationship to the conformationally-restricted anti-depressant Vivalan (2-(2-Ethoxy-phenoxymethyl)morpholine), the crystal-structures of the five compounds, (+) 1-(2-Hydroxy-3-isopropylaminopropoxy)-naphthalene hydrochloride, (+/-)1-(2-Eydroxy-3-isopropylaminopropoxy)-naphthalene hydrochloride, (+/-) 1-(4-Acetamidophenoxy)-3-isopropylaminopropan-2-ol perchlorate, (+/-)2-(2-Ethoxyphenoxy-methyl)morpholine oxalate and (+/-) 1-(2,6-Dichlorophenoxy)-3-isopropylaminopropan-2-ol hydrochloride have been determined and appropriate comparisons have been made. In addition, since the conformations of flexible molecules in the solid state need not necessarily correspond with the conformations which pertain in solution, the solid-state study has been matched by spectroscopic studies and by theoretical predictions of the free molecule conformation (both undertaken elsewhere). To date, neither of these latter projects have been completed, but where possible the solid state conformations have been compared with the conformations indicated by the other techniques. Part 3 is concerned with the elucidation of the molecular structures of the similar compounds, 6beta-(1-Ethyl-1-hydroxypropyl)-5dv-phenyl-2,3,5,6-tetrahydroimidazo [2,1-b] thiazole and 5,5-Diphenyl-6-oxo-2,3,5,6-tetrahydroimidazo [2,1-b] thiazole. In the former case, the method of synthesis may feasibly result in either of the two isomers, 6beta-(1-Ethyl-1-hydroxypropyl)-5ck-phenyl-2,3,4,5-tetra-hydroimidazo [2,1-b] thiazole or 5beta-(1-Ethy 1-1-hydroxypropyl)-6alpha-phenyl-2,3,5,6-tetrahydroimidazo [2,1-b] thiazole and since conventional spectroscopic techniques were unable to differentiate between these possibilities an X-ray analysis has been carried out. Spectroscopic studies of the minor product of the reaction of ethylene dibromide with 5,5-diphenyl-2-thiohydantoin showed apparent anomalies from expected results and in order to confirm the detailed molecular structure of 5,5-Diphenyl-6-oxo-2,3,5,6-tetrahydroimidazo [2,1-b] thiazole, an X-ray analysis has been carried out. The contents of Part 4 include a brief discussion of the various modes of pi bonding postulated for second-row ylides and since N-dichlorophosphinoyl-l-triphenylphosphazene and N-diphenylphosphazene may both be regarded as belonging to this class of compound, the crystal-structure analyses of both these ylides have been carried out in order to obtain further information regarding the bonding systems and conformations exhibited by second-row ylides. These results have also been compared with the known dimensions of similar bonding systems and appropriate comparisons have been made. Also included in Part 4 is the X-ray analysis of the final product obtained from reacting a methanolic solution of methyl 6beta-phenyl-acetamido-penicillanate with chloramine T, at room temperature. The spectroscopic analysis of this product revealed three possible structures and since one possibility was an unusual ylide, and since comparison of this compound with other ylide systems was thought to afford the opportunity for detailed investigations of bonding and conformational patterns within second-row ylide systems, the crystal structure analysis has been carried out and the compound characterised.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Organic chemistry
Date of Award: 1975
Depositing User: Enlighten Team
Unique ID: glathesis:1975-78657
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 30 Jan 2020 15:05
Last Modified: 30 Jan 2020 15:05

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