217088-67-0Relevant academic research and scientific papers
Spontaneous and direct transformation of N,O-diaryl carbamates into N,N′-diarylureas
Yamasaki, Ryu,Honjo, Yutaka,Ito, Ai,Fukuda, Kazuo,Okamoto, Iwao
, p. 880 - 884 (2018)
We have discovered a spontaneous reaction of N,O-diaryl carbamates to afford symmetrical N,N′-diarylureas. Optimization of the conditions indicated that N,N-dimethylformamide (DMF) was the best solvent and triethylamine (Et3N) was the best additive for this transformation. The reaction requires the presence of aryl groups on the nitrogen and oxygen atoms of carbamates. Substrates bearing an electron-donating methoxy group on either of the aryl groups reacted slowly under these conditions.
Multilevel selectivity in the mild and high-yielding chlorosilane- induced cleavage of carbamates to isocyanates
Chong, Pek Y.,Janicki, Slawomir Z.,Petillo, Peter A.
, p. 8515 - 8521 (2007/10/03)
The silane-induced cleavage of a series of N-p-tolylcarbamates and N- phenethylcarbamates to isocyanates has been investigated as a function of chlorosilane, carbamate substituent, and reaction conditions. Reaction yields were determined from the isolated ureas, which were formed by trapping the corresponding isocyanates with isobutylamine. Under room-temperature conditions, multilevel selectivity in carbamate activation has been demonstrated. This selectivity together with the generality of the methodology enhances the utility of carbamates as synthetic intermediates and protecting groups. To demonstrate the effectiveness of this selectivity, a series of biscarbamates were selectively monoactivated to isocyanates in excellent yields.
