compound 4-alpha-methylzymosterol C28H46O InChI=1S/C28H46O/c1-18(2)8-7-9-19(3)22-12-13-24-21-10-11-23-20(4)26(29)15-17-28(23,6)25(21)14-16-27(22,24)5/h8,19-20,22-24,26,29H,7,9-17H2,1-6H3/t19-,20?,22?,23+,24?,26+,27-,28+/m1/s1 CHEBI:1949 UPa:UPC05103 4alpha-methylzymosterol compound KEGG:C05103