That would be a pro-drug type of compound. I have made a lot of pro-drugs. One problem is that the pro-drug, your reduced caffeine palmitate, is also a potentially biologicaly active molecule, it could have unwanted (or wanted) effects on the human body. You could alkylate the "imidazole" nitrogen with chloromethyloxypalmitoate, this would give you a "Bundgaard" type of pro-drug. this would be a quaternized compound. Here are some references chatGPT suggested regarding modifications of the caffeine molecule: