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Chemgenes Corporation

Praveen K Shukla

Suresh C Srivastava

Alok Kumar Srivastava

Sant K Srivastav

Santhosh Kumar Thatikonda

Santhosh K Thatikonda

This invention is related to nucleic acid chemistry and describes novel 1,2-dithiolane functionalized nucleoside phosphoramidites (1, Chart 1) and corresponding solid supports (2, Chart 1). In addition to these derivatives, 1,2-dithiolane moiety can also be functionalized to at the various positions of the nucleobase and sugar part as shown in Schemes 1 to 8. The nucleosides of our invention carry a primary hydroxyl for DMTr (4,4'-dimethoxytrityl) function for chain elongation. Furthermore, the phosphoramidite function is attached at the 3&#x2032;-hydroxyl of the nucleoside. This allows oligonucleotide chain extension under standard DNA and RNA synthesis chemistry conditions and techniques, thus leading to high quality oligonucleotides. These derivatives are useful for introduction of reactive thiol groups either at 3&#x2032;- or 5&#x2032;-end of the oligonucleotides on the solid supports such as gold, silver and quantum dots.

Dithiolane functionalized nucleoside amidites and supports for stronger immobilization of bio-molecules on solid surfaces

The thiol modified oligonucleotides have vast number of applications in the field of nucleic acid chemistry. The conjugates generated by mono thiol groups are unstable at higher temperature, in high salt concentration buffers and in presence other thiols. There is strong need to develop a novel thiol modifier probes that can generate multiple thiol groups. Described herein are efficient processes and compounds, dithiolane phosphoramidites derivative and dithiolane succinyl supports. The advantage of our cyclic disulfide thiol modifier is multifold a) each incorporation introduces two thiol groups; b) it can be introduced at any desired site of oligonucleotides; c) The symmetrical branching nature of the spacer in the linker arm of dithiolane allows for clean oligo synthesis, where cleavage of the linker arm and thereby of loss of oligo chain is prevented. We have successfully made 20-mer oligonucleotide containing single dithiolane derivative at 3', and 21-mer oligonucleotides containing single dithiolane derivative at 5&#x2032; or in the middle of the mixed base sequence. HPLC and ESI MS analysis of these oligonucleotides indicated satisfactory purity and correct composition of these oligos, respectively.

Dithiolane based thiol modifier for labeling and stronger immobilization of bio-molecules on solid surfaces

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Burlington, MA, United States of America

Praveen K Shukla