1977-33-9 1990-07-4 4-((2,4-Dihydroxy-3,3-dimethyl-1-oxobutyl)amino)butanoic acid Butanoic acid, 4-((2,4-dihydroxy-3,3-dimethyl-1-oxobutyl)amino)- GABA pantoate GABA-pantoyl Homopantothenic acid Hopantenic acid Pantogab Pantoyl-GABA