The tetraribonucleoside triphosphates ApUpUpC(10),CpGpGpA(25) and the tetranucleotide ApUpUpCp(30) corresponding to 58-61 and 62-65 fragments of the yeast alanine transfer ribonucleic acid molecule together with another tetraribonucleoside triphosphate ApUpCpU (16) have been synthesized.As shown in Fig.1,2,3,and 4,protected tetranucleoside triphosphates and tetranucleotide were obtained by condensation of the appropriately protected dinucleotide with protected dinucleoside monophosphates or protected dinucleotides.The protected dinucleotides and dinuc;leoside monophosphates were prepared by coupling the appropriate protected nucleotide with proteoted nucleo ride and nucleoside respectively.