1-Thia-3,4-diazolidene-2,5-dione Derivatives: Precursors to Diimide, Carbenes , Carbonyls and Photodegrable Polymers

Sometimes a new functional group is discovered that shows a surprising range of new chemistry and is almost immediately of value to the synthetic chemistry community. We have recently begun looking at such a functional group, 1-thia-3,4-diazolidine-2,5-diones (I). This functional group and its derivatives are proving to be useful synthetically in several ways (see figure below). They represent an easy and facile route into the pharmaceutically useful 1,3,4-oxadiazolinone functionality (II) and it is useful as a photochemical hydrogenation reagent via diimide (III). In addition it can be used to generate several interesting reactive intermediates. Azo compounds (IV) can be produced photochemically in high yields from 3,4-dialkyl-1-thia-3,4-diazolidine-2,5-diones and this route should also lead to production of diazirines (V) and hence carbenes (VI). An interesting series of molecules which could be produced is the oxy-diazirines (VII). These hitherto unknown compounds could act as thermal precursors for carbenes or photochemical precursors for carbonyl compounds. Polymers based on this functional group have the potential to be true photodegradable polymers, i.e. polymers which can be photodegraded to only small innocuous compounds (VIII) as well as potential precursors for surface bound species (IX). Thus the 1-thia-3,4-diazolidine-2,5-dione functional group promises to be of wide-ranging use in organic chemistry and this project centers on establishing the versatility of this new functional group