The present invention relates to a method of preventing modification of a
synthetic oligonucleotide or oligonucleotide analog during removal of at
least one cyanoethyl protecting group from the oligonucleotide or
oligonucleotide analog. The method involves contacting the
oligonucleotide or oligonucleotide analog with a basic solution having at
least one acrylonitrile scavenger, such as t-butylamine, at a sufficient
temperature and for a sufficient period of time to remove at least one
.beta.-cyanoethyl protecting group. The present invention also relates to
a method of producing a synthetic oligonucleotide or oligonucleotide
analog.