# Investigation for the easy and efficient synthesis of 1H-benzo[d][1,3]oxazine-2,4-diones

## TL;DR

This paper presents a simple and efficient two-step method to synthesize 1H-benzo[d][1,3]oxazine-2,4-diones from 2-aminobenzoic acids.

## Contribution

The novel contribution is a streamlined synthetic route using specific carbonyloxy groups and thionyl chloride for efficient compound formation.

## Key findings

- A two-step synthesis method was successfully developed for 1H-benzo[d][1,3]oxazine-2,4-diones.
- The use of Fmoc, Cbz, and EtOCO groups as carbonyloxy sources proved effective.
- Thionyl chloride effectively promoted activation, cyclization, and compound formation.

## Abstract

We investigated a two-step approach for the easy and efficient synthesis of 1H-benzo[d][1,3]oxazine-2,4-diones starting from 2-aminobenzoic acids, using the urethane type fluorenylmethyloxycarbonyl (Fmoc), benzyloxycarbonyl (Cbz) and ethyloxycarbonyl (EtOCO) groups as the source of carbonyloxy group, and thionyl chloride to promote activation, cyclization and 1H-benzo[d][1,3]oxazine-2,4-diones formation.

We report the synthesis of 1H-benzo[d][1,3]oxazine-2,4-diones from 2-aminobenzoic acids, using fluorenylmethyloxycarbonyl (Fmoc), benzyloxycarbonyl (Cbz) and ethyloxycarbonyl (EtOCO) groups as the source of carbonyloxy group, and thionyl chloride.