Purification Methods
Crystallise the acid once from pet ether (b 60-80o), twice from 60% aqueous MeOH and finally from EtOH (m 100-101o). UV has max 207 and 260nm (log 4.64 and 4.28). [King et al. J Chem Soc 4011 1964, Schrecker & Hartwell J Org Chem 21 381 1956.]