1068-58-2 2-Methyl-2-thiopseudourea, monohydrobromide 2986-19-8 Methylisothiouronium bromide Psuedourea, 2-methyl-2-thio-, monohydrobromide S-Methylisothiourea hydrobromide S-Methylisothiuronium bromide USAF PD-31