David M. McKinnon

Carbon-13 nuclear magnetic resonance spectra of N-, O-, and S-methylated uracil and thiouracil derivatives

13C nmr chemical shifts have been recorded for a number of uracil, thiouracil, and pyrimidine derivatives. These data are discussed in relation to what is known of the lactam–lactim tautomerism in such systems and possible correlations of chemical shifts with normal aromatic substituent chemical shift parameters. The chemical shifts for the CH3 groups in simple methylated derivatives of uracil are very characteristic of the site of methylation and should prove useful as a tool for assigning structures to alkylated derivatives of this general type.

The preparation and properties of some thioacylmethylenethiazolines and isothiazolines

Thiazoline-2-thiones and isothiazoline-3-thiones are converted into the 2- or 3-thiophenacylidene derivatives, respectively, by reaction with phenacyl bromide, treatment with pyridine, and thionation. The former compounds react with dimethyl acetylenedicarboxylate to form mono- and diadducts as well as some decomposition products. Attempts to demonstrate valency isomerism in the 3-thiophenacylideneisothiazoline derivatives were unsuccessful.

OXIDATION PRODUCTS OF CYCLIC THIONES

Abstract A large number of cyclic thiones has been synthesized. These include alicyclic and heterocyclic thiones, the latter including those with potential aromatic character. It is the intention of this paper to summarize the reactions of a number of simple systems of this type with a variety of reagents which lead to modification of the thione function. Reactions may either lead to oxidation of the molecule, replacement of the thione sulfur atom by oxygen, or even replacement by hydrogen. Data are also included for some thiols which are capable of tautomerism with thiones and give similar or related products.

SOME INVESTIGATIONS ON BRIDGED AND POTENTIALLY BRIDGED ISOTHIAZOLES

Abstract This review deals with some investigations on isothiazoles and benzisothiazoles, where there is potential or actual bonding of the ring sulfur or nitrogen atom to an exocyclic atom, to form an extra ring. The possibility of interactions due to hypervalent sulfur or polarizability effects is discussed.

A novel solvolytic rearrangement of 2,2-dimethyl-5-(1-Bromomethylethylidene)-1, 3-dioxane-4,6-dione

Abstract Treatment of the title compound under basic aqueous conditions leads to 2,2-dimethyl-5-(2-ketopropyl)-1,3-dioxane-4,6-dione; the structure and mechanism of formation of this compound is described.