Carbamate Synthesis Using a Shelf-Stable and Renewable C₁ Reactant

Area of Science:

• Green Chemistry
• Organic Synthesis
• Renewable Feedstocks

Background:

• 4-Propylcatechol carbonate is a stable, renewable C1 reactant.
• It is synthesized from wood-derived 4-propylcatechol and CO2-derived dimethyl carbonate.
• Reactive distillation facilitates its efficient preparation.

Purpose of the Study:

• To utilize 4-propylcatechol carbonate for a two-step carbamate synthesis.
• To achieve synthesis under mild reaction conditions.
• To demonstrate the recyclability of the byproduct.

Main Methods:

• A two-step reaction sequence was employed.
• Step 1: Reaction of 4-propylcatechol carbonate with alcohols (50-80°C) using a Lewis acid catalyst (Zn(OAc)2·2H2O).
• Step 2: Reaction of intermediate alkyl 2-hydroxy-propylphenyl carbonates with amines at room temperature in 2-methyltetrahydrofuran.

Main Results:

• The synthesis of carbamates was achieved under mild conditions.
• The process yielded target carbamates and 4-propylcatechol as a byproduct.
• The byproduct 4-propylcatechol can be recycled for reactant regeneration.

Conclusions:

• 4-Propylcatechol carbonate is an effective and sustainable reactant for carbamate synthesis.
• The developed method is efficient, operates under mild conditions, and incorporates a circular economy principle through byproduct recycling.
• This approach contributes to greener synthetic strategies in organic chemistry.