Patent ID: 6153742
Filing Date: 2000-11-28
Classification: C07H,Y02P

Abstract:
A process for preparation of a single stranded cyclic oligonucleotide of formula (I), or a salt or solvate thereof, by solid phase synthesis ##STR8## wherein the B groups in the oligonucleotide of formula I are the same or different from each other and each B is selected from the group consisting of endocyclic nitrogen radicals of nucleobases, each of said nucleobases being selected from the group consisting of thymine, uracil, adenine, cytosine and guanine (T, U, A, C or G); the oligonucleotide of formula I has a plurality of furanose groups with 3'-hydroxy groups and 5'-hydroxy groups which are the same or different from each other, are substituted at said 3'-hydroxy groups and 5'-hydroxy groups, and are biradicals of D-2-deoxyribofuranose or biradicals of D-ribofuranose; and n is an integer between 0 and about 50; said process comprising the steps of:a) protecting and anchoring a nucleotide of formula (IV) having a 3'-terminal phosphate group and a 5'-hydroxy group to a polymeric support via said phosphate group, ##STR9## wherein B' is a radical of one of said nucleobases, said radical not being protected when said nucleobase is said thymine or said uracil, and being protected with a protecting group bound to an exocyclic amine group when said nucleobase is said adenine, cytosine or guanine; R.sub.3 is a protecting group of the 5'-hydroxy group and is structured for chain elongation; R.sub.2 is a protecting group bound to the 3'-terminal phosphate group; X is a biradical consisting of an anchoring group bound to the 3'-terminal phosphate group and to a polymeric support (P) to protect as well as anchor said phosphate group to the polymeric support (P) and P' is a radical of said polymeric support (P) or a radical of a modified polymeric support including a spacer/bonding group;b) after the protecting and anchoring of the nucleotide of formula (IV) in step a), removing the protecting group R.sub.2 of the 3'-terminal phosphate group;c) performing a chain elongation consisting of a sequence of n+1 chain elongation steps using a nucleotide having a predetermined one of said nucleobases in each of said chain elongation steps; wherein said nucleotides used in said chain elongation steps each have 5'-hydroxy groups and a 3'-phosphate group and protecting groups R.sub.3 bound to said 5'-hydroxy groups to protect said 5'-hydroxy groups; said protecting groups R.sub.3 are equal or different from each other and structured for said chain elongation; said nucleotides used in each of said chain elongation steps are protected at said 3'-phosphate group with a chain phosphate protecting group R.sub.1, said chain phosphate protecting groups R.sub.1 are the same or different from each other, and are selected so that R.sub.2 and R.sub.3 are removable under conditions in which a bond between the anchoring group X and P', the protecting group R.sub.1 and the protecting groups of said adenine, cytosine or guanine in said B' remain unaltered; so that a protected and anchored intermediate oligonucleotide of the formula (III) is obtained; ##STR10## d) removing said protecting group R.sub.3 and said protecting group R.sub.2 of the anchored intermediate oligonucleotide (III) if said protecting group R.sub.2 was not previously removed sequentially in any order to form a resulting product; cyclizing the resulting product in the presence of a cyclizing reagent to obtain a cyclized, anchored intermediate of the formula (II); ##STR11## e) removing the protecting groups R.sub.1 from the 3'-phosphate groups in the cyclized anchored intermediate (II), cleaving the cyclized anchored intermediate (II) from the polymeric support and removing the protecting groups of the adenine, cytosine or guanine in said B' groups to form said cyclic oligonucleotide of formula (I); andf) isolating said cyclic oligonucleotide of formula (I), or said salt or said solvate thereof.