Glen Research offers a selection of 5’-Amino-Modifiers with a variety of chain lengths to fit exactly the desired application
6-(N²-methyl-N¹-phthalimidyl)-hexyl-1-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite
12-(N²-methyl-N¹-phthalimidyl)-dodecyl-1-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite
10-(N²-methylphthalimidyl-N¹-ethyl)-triethyleneglycol-1-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite