I have a large tax bill this year , but will have a large loss next year due to default on loan I made. Can I file amended tax next year to regain this years tax paid?

I made a hard money real estate loan in 2017 for $200K. It is in default, and the 1st position (I am in 2nd) is foreclosing but it hasn't gone to auction yet. Last year I sold (closed on 31 Dec 2018) property on which I will owe about $75K Federal tax on my 2018 return. Can I offset the tax due with the loss on the defaulted loan? How about the $20,000 interest that was due on the defaulted loan and not paid? If not, perhaps because it hasn't yet been closed out yet, can I file amended tax returns in future years when the loss on the loan has been determined and recover some of the 75K tax I will have to pay this year?

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