The use of gaseous ammonia for the deprotection and cleavage steps during the solid-phase synthesis of oligonucleotides, and analogs

The use of NH3 gas under pressure offers an efficient alternative to hot aqueous ammonium hydroxide for the deprotection, and cleavage steps during the large-scale synthesis of oligonucleotides, and their analogs prepared using N-pent-4-enoyl (PNT) nucleoside phosphoramidites and H-phosphonates.