1-Piperazineethanol, 4-(diphenylmethyl)-alpha-(4-hydroxyphenyl)-beta-methyl-, (R*,R*)-(+-)-, (R-(R*,R*))-2,3-dihydroxybutanedioate (2:1) (salt) 87429-93-4 dl-erythro-2-(4-Diphenylmethylpiperazinyl)-1-(4-hydroxyphenyl)propanol semitartrate