Health & Environmental Research Online (HERO)


Print Feedback Export to File
6953171 
Journal Article 
Expedient phosgene-free synthesis of symmetrical diarylureas from carbamates 
Elghamry, I; Abdelsalam, M 
2019 
2019 
6 
83-92 
English 
WOS:000521363100008 
A convenient method for synthesis of symmetrical diarylureas from carbamtes is reported. The diarylureas were obtained in excellent yield when carbamates were boiled at reflux in dry benzene in the presence of sodium hydride as a catalyst and 18-Crown-6 (18C6) as a co-catalyst. A plausible mechanism explains the formation of 1,3-diarylureas from carbamates in the presence of basic catalyst is reported. The chemical structure of the diarylureas was confirmed by spectroscopic techniques and compared with an authentic sample prepared using previously reported methods. O O Ar R Ar NaH/dry benzene/18C6 Ar N O 3 h, 80- 90% yield N N H H H 1a-h 2a-d © ARKAT USA, Inc 
Carbamates; phosgene free; symmetrical diaryl urea; 18-crown-6