In addition to carboxylic acids or acid chlorides, one skilled in the art will recognize that compound 2 may be made to react with a number of other readily available raw materials to provide compounds of formula I. For example, compound 2 may be made to react with sulfonyl chlorides (e.g.; R5SO2Cl) in the presence of an acid scavenger to provide compounds of formula I where J is a bond and R3 is