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      https://www.ias.ac.in/article/fulltext/jcsc/128/06/0875-0881

    • Keywords

       

      Carbodiimide; isocyanate; guanidine; urea; Zn catalyst; guanylation.

    • Abstract

       

      We report the highly chemo-selective catalytic addition of N–H bonds from various aromaticamines to carbodiimides and isocyanates using (Ar-BIAO)ZnCl2 complexes [Ar-BIAO = N-(aryl)iminoacenapthenone,Ar = 2,6-$Me_{2}C_{6}H_{3}$ (1), 2,4,6 $Me_{3}C_{6}H_{2}$ (2), $2,6-^{i}$ $Pr_{2}C_{6}_H{3} (3)] as the pre-catalyst to prepareguanidine and urea derivatives in 55-90% yield. The complex 3 showed higher catalytic activity than analogouscomplexes 1 and 2 under similar reaction conditions. The catalytic guanylation of N–H bonds with heterocumulenesdisplays a broad substrate scope. The amines having electron donating groups underwent higher conversionthan the amines having electron withdrawing groups to afford corresponding guanidine or urea derivatives.A possible mechanism involving penta-coordinated zinc transition state for the catalytic reaction is presented.

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  • Journal of Chemical Sciences | News

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