New CO₂ chemistry for fine chemical synthesis

There is a great need in the chemical industry for developing CO2 as a C1 building block as an important step towards "green chemistry". CO2 is also attractive as a chemical feedstock because it is readily available, inexpensive, nontoxic and it can replace toxic building blocks such as phosgene and CO. Industrially, megatons of CO2 are used each year for the production of urea, inorganic carbonates, salicylic acid, and polycarbonates, yet this is still miniscule compared to the immense potential that is still yet to be harnessed in using this versatile building block. This thesis discusses how a novel methodology was developed for synthesising a benzotriazole (Bt) urea directly from CO2 in a two-step, one-pot synthesis. The procedure involves trapping CO2 with a primary or secondary amine in the presence of DBU, and reaction of the resultant carbamate salt with triphenylphosphine and chlorobenzotriazole (BtCl) to produce Bt ureas in moderate to high yields. The Bt group may serve as a leaving group in nucleophilic substitution reactions, therefore it is also shown here how the Bt urea presents itself as a precursor for an array of useful organic intermediates. These intermediates include ureas, amides, S-thiocarbamates and sulfonylureas.

Grantor dc:publisher.institution

Department of Chemistry

Year dc:date.issued

2011

Author dc:creator

• Msutu, Ath'enkosi

Advisor dc:contributor.advisor

• Hunter, Roger

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/13102

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/13102