# Ferrocenoylation of Uracil Derivatives: Study of Reaction Regioselectivity and Biological Activity

## TL;DR

This paper studies how to attach ferrocene groups to uracil at specific positions and evaluates the biological activity of the resulting compounds.

## Contribution

The study identifies optimal conditions for regioselective N-ferrocenoylation of uracil and demonstrates the biological activity of the products.

## Key findings

- Reactions in DMF produce only the N1 product, while reactions in CH3CN yield N1 and N1/N3 products.
- Extended reaction time and triethylamine maximize yield of N1/N3-diferrocenoyl uracil.
- The conjugates show oxidative and immunomodulatory activity, indicating biological potential.

## Abstract

The N-ferrocenoylation of uracil was studied to evaluate regioselectivity and optimise preparation protocols. Regioselectivity was monitored under various reaction conditions, with particular attention paid to the effects of the solvent and the base. Reactions in DMF were regiospecific, yielding only the N1 product, while reactions in CH3CN produced both N1 and N1/N3 products, with ratios depending on the reaction conditions. The highest yield of N1/N3-diferrocenoyl uracil was achieved with an extended reaction time of 90 min using uracil and triethylamine. Optimised conditions were applied to C5-uracil derivatives, producing N1 and N1/N3 products. Regioselectivity and N-substitution were confirmed by NMR, and solvent effects were supported by quantum chemical calculations. The resulting ferrocene–pyrimidine conjugates exhibited oxidative and immunomodulatory activity, highlighting their biological potential.