We don't have synonyms for morpholino yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are morpholine.
(n) :
(genetics) A structural analog of natural nucleic acid used to modify gene expression, in which the ribose or deoxyribose rings of nucleic acids are replaced with morpholine rings and the phosphodiester intersubunit linkages of nucleic acids are replaced with phosphorodiamidate linkages.
(n) :
(genetics) A structural analog of natural nucleic acid used to modify gene expression, in which the ribose or deoxyribose rings of nucleic acids are replaced with morpholine rings and the phosphodiester intersubunit linkages of nucleic acids are replaced with phosphorodiamidate linkages.