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Title: Studies on the chemistry of benzothiazines and thiochromones
Author: MacKenzie, Neil E.
ISNI:       0000 0001 3615 4958
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1979
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In Chapter 1 the history of the isolation and synthesis of the trichochrome pigments, responsible for the red colouration of hen feathers and human hair, is described followed by a review of the ring-contractions of 6-membered sulphur heterocycles including condensed 1,4-thiazines. In Chapter 2,3-aryl-2H-1,4-benzothiazine, equivalent to half the trichochrome structure, are elaborated by oxidation, azo coupling, and condensation with aromatic aldehydes. Tautomerism of the 2-aryl- hydrazono derivatives obtained is investigated in some detail. Tetrazines obtained as a by-product of the azo coupling reactions are also discussed. In Chapter 3 further attempts to increase the conjugation of the 3-aryl-2H-1,4-benzothiazines led to the formation of novel 3-aryl-3-hydroxy-2,3-dihydronaphtho-1,4-thiazine 5,10-quinones, the chemistry of which was studied including an interesting modification to the Puimnerer rearrangement. In Chapter 4 the chemistry of 3H and 1H phenothiazinones is reviewed. While new 3H-phenthiazin-3-ones were prepared, all attempts to isolate new 1H-phenothiazin-l-ones failed. Included in this Chapter is a discussion (with model reactions) of the substitution and addition chemistry of naphtho-1,2- and -1,4-quinones. Finally in Chapter 5 the ring contraction reactions of cyclic sulphoxides are discussed and studied extensively. This led to the elucidation of the reaction pathway for the formation of thioindigo from 4-thiochromanone which involves a novel ring contraction.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available