Synthesis of modifiable targets using benzothiazoles as formyl synthons in template-directed solid-state synthesis

ORGN 266

Poonam Kaushik, poonam-kaushik@uiowa.edu and Leonard R. MacGillivray, len-macgillivray@uiowa.edu. Department of Chemistry, University of Iowa, Chemistry Building, Iowa City, IA 52242-1294
We are involved in developing a synthetic method that utilizes templates to direct the reactivity of molecules within hydrogen-bonded assemblies in solids. We have shown that cocrystallization of resorcinol with trans-1,2-bis(4-pyridyl)ethylene produces hydrogen-bonded assemblies that undergo photochemical [2+2] reaction to produce the corresponding cyclobutane product with a controlled stereochemistry, namely rctt-1,2,3,4-tetrakis(4-pyridyl)cyclobutane. This approach has been used to construct biologically-relevant ladderanes as well as cyclophanes. Owing to the architecture of molecular assemblies in our studies, the molecules constructed via template-directed solid-state syntheses are pyridine derivatives. Although templates have been shown to provide a general means to control bimolecular reactivity in the solid state, the stability of pyridines toward chemical modification can limit the products in downstream synthetic applications. To explore a possible alternative to pyridines, we have investigated benzothiazoles as hydrogen-bond acceptor groups. The benzothiazole ring has been used as a formyl group equivalent in solution-phase organic synthesis. This presentation will illustrate our results in using the benzothiazole functionality as a functional group alternative to pyridines in template-controlled solid-state synthesis to obtain easily-modifiable targets.