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One‐Step Synthesis of 2‐Amino‐5 H ‐pyrimido[5,4‐ b ]indoles, Substituted 2‐(1,3,5‐triazin‐2‐yl)‐1 H ‐indoles, and 1,3,5‐Triazines from Aldehydes
Author(s) -
Biswas Subhasish,
Batra Sanjay
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200276
Subject(s) - chemistry , amidine , guanidine , indole test , yield (engineering) , hydrochloride , reaction conditions , medicinal chemistry , combinatorial chemistry , catalysis , reaction mechanism , stereochemistry , organic chemistry , materials science , metallurgy
An efficient one‐step synthesis of 2‐amino‐5 H ‐pyrimido[5,4‐ b ]indoles through a copper‐catalyzed cascade reaction between 3‐haloindole‐2‐carbaldehydes and guanidine hydrochloride is described. In contrast, the base‐mediated reactions of either 3‐haloindole‐2‐carbaldehydes or substituted indole‐2‐carbaldehydes with substituted amidine hydrochlorides in DMSO result in the formation of 2‐(1,3,5‐triazin‐2‐yl)‐1 H ‐indole derivatives in one step in excellent yields. Studies toward exploring the utility of the method demonstrate that even substituted benzaldehydes undergo a similar reaction to efficiently yield 2,4,6‐trisubstituted 1,3,5‐triazines. A plausible mechanism for the formation of substituted 1,3,5‐triazines identifies the role of DMSO as an oxidant during the reaction.