MOESM5 of Efficacy and safety of a novel topical agent for gallstone dissolution: 2-methoxy-6-methylpyridine ChoiHo ChoSuk KimOk-Hee SongJin HongHa-Eun LeeSang KimKee-Hwan YouYoung HongTae KimEun ParkJung NaGun YouDong HanJae ParkJae KwakBong LeeTae AhnJoseph LeeHwan KangSeung HwangKyu-Seok JungJae-Kyung JungKwan-Young KimSay-June 2019 Additional file 5.  The change of NMR spectroscopy of MTBE with increasing Co2+ cation.