halogenating agent preferably oxalyl chloride or bromide the free 5 carboxylic acid or salt may also be converted to the acid halide by treatment with conventional agents employed in the production of acid halides such as pcl 5 pcl 3 pocl 3 socl 2 and the like in the presence of an acid acceptor such as pyridine the n protected tetrazole 5 carbonyl halide products and the intermediates formed in their production represent the compound aspect of this invention the carbonyl halide products are intermediates useful in the production of antiallergic agents such as are disclosed in our co pending application ser no 669 570 filed march 23 1976 now u s pat no 4 013 647 in practice the n protected tetrazole 5 carbonyl halides of this invention are condensed with a desired amine and the protective group of the tetrazole is removed to yield the desired anti allergic agent thus the n protecting group present in the initial azide reactant is carried through the entire reaction sequence leading to the desired anti allergic agent hence the protecting group r 1 ch 2 must be stable under all reaction conditions involved in the multi step process resulting in the production of a desired ultimate compound while having the attribute of.