prov:value
| - In formulae (C1) and (C2), R1 and R2 each are hydrogen or a straight, branched or cyclic alkyl group of 1 to 20 carbon atoms, which may contain a hetero atom such as oxygen, sulfur, nitrogen or fluorine, R3, R4, R5 and R6 each are a straight, branched or cyclic alkyl group of 1 to 20 carbon atoms, an aryl group or an aralkyl group, which may contain a hetero atom such as oxygen, sulfur, nitrogen o
|