prov:value
| - , a cyano group, a carboxyimide group, an isocyanate group, an isothiocyanate group, an azide group, a sulfonic acid group, a sulfonamide group, a halogenated sulfonyl group, a halogenated carbonyl group, an N-succinimidyloxycarbonyl group or an N-phthalimidyloxycarbonyl group; R1 is a halogen atom, an alkyl group or an aryl group; R2, R3, R4 and R5 which may be the same or different represent a h
|