That depends on the modification, but in general, we obtain a 20-40% isolated yield of triphosphate >90% pure (and often >95%) if the nucleoside is clean and behaves normally. That translates very roughly into 10-15 μmoles of nucleotide. The yield can be much lower or higher in any individual case.
The answer depends on many factors, beginning with how easy it is to prepare your particular compound. In general, we are willing to consider quoting on kilogram or multi-kilogram quantities of straightforward phosphoramidites, such as our linkers. We are able to prepare modified nucleotides in 10 grams or more per single synthetic prep if the purification is not problematic. Before we consider a large scale synthesis, we will try it on a much smaller scale first. We can also prepare multiple smaller synthetic batches (this reduces risk to both parties) that can be recombined prior to analysis to prepare single large lots. Please contact us to discuss your particular project.
A phosphoramidite is the actual building block we use to chemically synthesize oligonucleotides. It usually consists of a protected nucleoside with a 3’ phosphitylating reagent, where phosphorus is in the trivalent state and protected with a stable amine and ester. The amine is activated during synthesis with acid, producing a good leaving group. The phosphorus is then attacked by the 5’ hydroxyl of the growing oligonucleotide chain. After coupling, the phosphorus is oxidized to the pentavalent phosphorus state using iodine and water.
Before we agree to do a triphosphate conversion, we need to look at the structure of your specific modified nucleoside. Based on the structure, we can determine whether or not we will be able to convert it to a triphosphate. You will only be charged if we are successful in the conversion.