# Green-Light Photocatalysis: Borylated Benzo[c][1,2,5]thiadiazole (BTZ) Enables Phosphorylation of Quinoline Derivatives

## TL;DR

Scientists developed new green-light photocatalysts that efficiently phosphorylate quinoline compounds, enabling streamlined antibacterial drug production.

## Contribution

A novel library of green-light-responsive photocatalysts enables efficient phosphorylation and automated synthesis of antibacterial compounds.

## Key findings

- The new photocatalysts achieved up to 73% conversion in phosphorylation under recycle flow conditions.
- A dual photocatalyst system enabled a two-step phosphorylation and Minisci coupling process for antibacterial compound synthesis.
- The process uses low-energy green light and inexpensive starting materials for streamlined drug production.

## Abstract

A library of 10 novel organophotocatalysts (ORG-PRCs) has been prepared by the one-pot, two-step ortho-borylation of 4,7-diarylbenzo­[c]­[1,2,5]­thiadiazoles
(BTZs). The borylation reaction was accompanied by a
substantial bathochromic shift in both the absorption and emission
spectra (up to 142 nm), allowing these photocatalysts to operate using
low-energy green light instead of the high-energy near-UV light that BTZ photocatalysts typically require. The library of photocatalysts
was tested using the phosphorylation of quinoline compounds under
both batch and recycle flow conditions, achieving up to 40 and 73%
conversion, respectively, in 4 h. The versatility of the recycle flow
system was further tested by developing a sequential two-step phosphorylation
followed by a Minisci coupling procedure using a dual photocatalyst
system. This allowed automated production of the target antibacterial
phosphorylated quinoline derivative with a total conversion of 64%
from abundant, inexpensive, and late-stage modifiable starting materials
in a streamlined process.