... Identity was indi- cated by comparison with literature data (20) and established by comparison with a synthetic sample. ... VOL. ... for C1,H2,O4 (M+): 278.1518; found: 278.1522 (4), 260 (38), 247 (42), 233 (36), 229 (loo), 218 (24), 203 (21), 201 (41), 188 (20), 187 (52), 173 (31), 171 ...