DEprotEction VolumE 4 AltErnAtiVES to
St with my equipment and purification strategy
DEprotEction VolumE 4 AltErnAtiVES to Ammonium HyDroXiDE
Back in the 1990s, deprotection of DNA oligos was carried out using ammonium hydroxide overnight at 55 . the only option to increase the speed was to raise the deprotection temperature to 80 (and even above!) with the time being halved for every 10 the temperature was increased. But in those days, the most common application for oligos was as sequencing primers so a small percentage of unprotected ibu-dG was never noticed. the first attempt to increase the speed of deprotection was the introduction1 of dmf-dG (and dmf-dA) as “fastphoramidites” since dmf-dG is deprotected at about twice the rate of ibudG. In our view, there was no downside to the adoption of dmf-dG but dmf-dA proved to be rather too labile for routine use and was discontinued. However, ammonium hydroxide was still the only deprotection method at this time. Although ammonium hydroxide is still immensely popular for deprotection of DNA oligos, the advent of high throughput synthesis, labile bases and fluorescent tags has led to the adoption of a variety of newer procedures.2565656-71-3 Synonym In this article, Deprotection Volume 4, we will describe some of the most popular deprotection procedures and will note when they may be most applicable. As usual, when reviewing the variety of procedures available to deprotect any modified or unmodified oligonucleotide, you must heed the primary consideration: First, Do No Harm.81409-90-7 site you can then proceed with confidence to Deprotect to Completion. FIrst, do no Harm! As we have stated in the past, determination of the appropriate deprotection scheme should start with a review of the components of the oligonucleotide to ascertain if any group is sensitive to base and requires a mild deprotection or if there are any pretreatment requirements. sensitive products are defined as such on the Analytical Report, certificate of Analysis, or technical Bulletin. occasionally, some products require a special pretreatment to prevent unwanted side reactions. If the oligo has several unusual components, you must follow the mildest procedure recommended. As you might expect, some highly modified oligos can become VeRy challenging. ultraFast deprotectIon the use of dmf-dG to speed up deprotection with ammonium hydroxide was only an incremental improvement in speed.PMID:29999881 However, ultrafast deprotection quickly became a commercial reality with the introduction2 of deprotection using using ammonium hydroxide/methylamine (AmA). By adding an equal volume of 40% aqueous methylamine solution to ammonium hydroxide to form AmA, it is possible to speed up the deprotection of oligonucleotides enormously.2 Deprotection can be completed in 5 minutes at 65 , thereby allowing oligonucleotides to be delivered to customers on the same day of manufacture. the only change required in the synthesis strategy is the substitution of Ac-dc for Bz-dc to avoid transamination of dc by displacement of benzamide by methylamine to form the mutant N4-medc.3 this modification is well tolerated and probably codes perfectly as dc in any case. However, as with dmf-dG described above, we see no downside to the use of Ac-dc and recommend it at all times. ultrafast deprotection has found favor with groups processing many oligonucleotides where the decreased processing time, and, therefore, cost savings, becomes highly significant. options for ultrafast deprotection, where the removal of the dG protecting group is.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
