Pyridylmethylsulfonamide series were the first reported example of positive allosteric modulators (PAM) of the mGlu(2) receptor. The hydroxyacetophenone scaffold is a second series of mGlu(2) PAMs we have identified. This series of molecules are potent mGlu(2) potentiators and possess significant CysLT1 (cysteinyl leukotriene receptor 1) antagonist activity, showing in vivo efficacy in a dural plasma protein extravasation (PPE) model of migraine. In this paper, we describe the dual SAR, pharmacokinetics and preclinical in vivo efficacy data for a tetrazole containing hydroxyacetophenone scaffold. (C) 2016 Elsevier Ltd. All rights reserved.