Microwave-assisted synthesis of indole- and azaindole-derivatives in water via cycloisomerization of 2-alkynylanilines and alkynylpyridinamines promoted by amines or catalytic amounts of neutral or basic salts

Microwave-assisted synthesis of nitrogen-containing heterocycles

“…Earlier, the same group [34] produced similar indoles in moderate to good yields (16-77%) from same reactants 37 under MW irradiation in water without any added metal catalyst, acid, or base in 0.25-1.5 h.…”

Efficient synthesis of indoles from 2-alkynylaniline derivatives in water using a recyclable copper catalyst system

“…1,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] In particular, the introduction of transition metal reagents as catalysts (such as palladium, [19][20][21][22][23][24] gold, 5,10,14,25-28 rhodium, [29][30][31][32] ruthenium, 27,31,[33][34][35][36] platinum, 37 copper 6,18,22,[38][39][40][41][42][43][44][45][46][47][48] ) has deeply improved on the synthesis of indole and its derivatives. Among them, the ring closing of 2-ethynylaniline derivatives or their precursors (such as 2-bromo-anilines), 5,[49][50][51][52] which can be easily provided by well-established procedures, is one of the most efficient and basic app...…”

Microwave‐Assisted Synthesis of Substituted Pyrrolo[2,3‐d]pyrimidines

“…[15] The reaction of 4-amino-5-bromopyrimidine through ketone αarylation with acetophenone provides the 6-phenylpyrrolopyrimidine in 62 % yield. [17,18] Despite the wide range of methods available for the preparation of pyrrolopyrimidines, very few of them provide an efficient procedure with which to obtain the heterocyclic system with a range of substituents. The cyclization reaction of 2-alkynylanilines constitutes an interesting procedure with which to obtain 2-substituted indoles, azaindoles or other heterocyclic cores including pyrrolopyrimidines.…”