We have studied the reactions between adenosine 5'-phosphorimidazolide and 9-(2-amino-2-deoxyxylofuranosyl) adenine (I) or 3'-methylamino-3'-deoxy-adenosine (II), both with and without a poly (U) template. We find that both amino compounds react much more rapidly than does adenosine, in the absence of a template. The rate of reaction is greatly enhanced by a poly (U) template in the case of I, but the enhancement is slight in the case of II.