Convenient and efficient methods of the synthesis of N6-and N4-substituted derivatives of adenine and cytosine and their 2′-deoxyribosides were developed. The reactions of either unprotected nucleobases (adenine, cytosine) or unprotected 2′-deoxyribosides with aryl or alkyl aldehydes give corresponding Schiff bases that can be reduced to the target title compounds with high overall yields. In the case of aryl aldehydes the imine derivatives are ...