The present invention relates to compounds of formula (I):or pharmaceutically acceptable salts thereof, wherein R1, R2, X, Y, and HET are as defined herein. The invention also relates to pharmaceutical compositions comprising these compounds, methods of using these compounds in the treatment of various diseases and disorders, processes for preparing these compounds and intermediates useful in these processes本發明係關於式(I)化合物：或其醫藥學上可接受之鹽，其中R1、R2、X、Y及HET如本文所定義。本發明亦係關於包含此等化合物之醫藥組合物、使用此等化合物治療各種疾病及病症之方法、製備此等化合物之製程及適用於此等製程之中間物。
