Substituting maple syrup for maple extract

I would take some of the maple syrup that you have and cook it down in to granulated Maple Sugar. A tutorial is here. Then, as maple sugar is about twice as sweet as regular sugar, substitute it into your recipe accordingly. That should help infuse your scones with additional maple goodness.

"Pure" maple extract is made by concentrating the alcohol soluble aroma molecules, although artificial or natural maple extract may use barks or other ingredients entirely, potentially using oil, heat, chemical isolation processes, or alcohol to create an aroma compound that smells like maple.

You may be able to make your own maple extract by infusing maple syrup in alcohol, but I'm not sure how effective that will be; my own fruit infused liqueurs can take anywhere from a week to a year to mature. Just reducing the syrup by boiling it is unlikely to produce the result of the recipe you're working with, although there's a good chance it would taste just fine.

If I just wanted to avoid spending the 8 bucks on the extract, I might try making my own extract with a high-proof rum or vodka (100-150 proof considering you're just mixing with a mild-smelling sugar), but I'm not sure it would be worth the effort, considering I'd be buying maple syrup and liquor at retail prices for that purpose, and the odds are pretty good that the result won't actually be superior to a commercial product. Food producers can buy neutral grain spirits at something on the order of $1/liter, and it's unlikely that you can. They also have various techniques and equipment at their disposal that you probably won't be able to replicate.

Concentrated maple syrup is not very intense in flavor, and you're further diluting it with the flour and butter when you make scones. The function of the extract is to heighten the perception of flavor that's lost in the process of mixing with other ingredients. You may get very good results without the extract, but I'm sure the flavor will be fairly subtle and almost unnoticeable if you aren't looking for it.

With your reworded question, realistically, you're going to need more than just a quantity of maple syrup to simulate the extract, because you're most likely going to cause caramelization if you reduce maple syrup to the point where the intended flavor is achieved, and then you'll have "maple caramel", most likely, a pleasant but distinctly different flavor than the alcohol soluble aroma compounds in an extract would add.