Abstract

The preparation of 6-alkoxy- and 6-ary 1oxy-5-diazo-l,6- -dihydrouracils, from 5-diazouracil, is presented. A synthetic route to the parent compound, 5-diazo-l,6-dihydrouracil, is described and the EI-MS and FAB-MS of these novel compounds are given. The modified heterocyclic bases of nucleic acids often show biological activity, in particular, bases modified at the C-5 position of uracil. It is hoped that these compounds will show antibiotic and antitumour activity.

The reaction of diazouracils with dmso led to the formation of 5.5- dimethy1-1,3,2-dioxathio1oC3,4-d]pyrimidines and the reaction with olefins resulted in the isolation of furanoC2,3-d]pyrimidines. A 1,3-dipolar mechanism for the above reactions is presented.

The thermal decomposition of 5-diazouracil and 5-diazo-6- -methoxy-l,6-dihydrouracil with a variety of reagents was investigated. Reaction with alcohols afforded 5-alkoxy- and 5.6- dia1koxy- uracils. 5-Methoxyuracil was obtained in the reactions of 5-diazo-6-methoxy-l,6-dihydrouraci1. This suggested an intramolecular rearrangement of the intermediate obtained from the loss of the diazo group, and this was explored by isotopic labelling.

Additions of amines to the diazouracil gave a variety of 3-substituted 5(1-triazeno)uraci1s. An attempt to form an azaxanthine by the cyclisation of one of the isolated products, 5(3-propy1-l-triazeno)uraci1, was undertaken.

The formation of 3,3a,5a,6,7,8-hexahydro-4H,8H-pyrazolo- -13, 2:7,7alfurano[2,3-d]pyrimidin-7,9-dione via the addition of allyl alcohol to 5-diazouracil is reported.

Two approaches to the synthesis of 5-diazo-6H-uridine were attempted. One of the methods involving diazo transfer was found to be more promising resulting in the impure, desired product.

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Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > QD Chemistry
Departments:	School of Science & Technology School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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