About: http://webisa.webdatacommons.org/127488296

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	R3 and R4 in the general formula (II) are, respectively, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, such as methyl group, ethyl group, propyl group and butyl group, similarly to R1 and R2 described above.
http://www.w3.org/ns/prov#wasQuotedFrom	google.es