The invention relates to compound of the formula Iin which the substituents are as defined in the specification in free form or in salt form to its preparation, to its use as medicament and to medicaments comprising it.本發明係關於式I之化合物其中各取代基係如說明書中所定義;其呈游離形式或呈鹽形式;係關於其製備、其作為藥劑之用途及包含其之藥劑。(無元件符號說明)