.beta.,.beta.-Dimethacrylic acid .beta.,.beta.-Dimethylacrylic acid .beta.-Methylcrotonic acid 2-Butenoic acid, 3-methyl- 3,3-Dimethylacrylic acid 3-Methyl-2-butenoic acid 3-Methylcrotonic acid 541-47-9 Crotonic acid, 3-methyl- NSC97179 Senecioic acid WLN: QV1UY1&1