- Dibenzo-fused seven-membered nitrogen heterocycles by a tandem reduction-lactamization reaction
-
Efficient syntheses of dibenz[b,f][1,4]oxazepin-11(10H)-one, 5,10-dihydro-11H-dibenzo[b,e][1,4]-diazepin-11-one and 5,11-dihydro-6H-dibenz[b, e]azepin-6-one are described using a tandem reduction-lactamization sequence. Precursors for these ring systems are available in 1-3 steps using nucleophilic aromatic substitution and Ullmann coupling methodology. Direct reduction-lactamization of these compounds using iron powder in acetic acid at 115° affords the target heterocycles in ≥90% yield.
- Bunce, Richard A.,Schammerhorn, James E.
-
p. 1031 - 1035
(2007/10/03)
-
- Process for the preparation of 1-aminoanthraquinone
-
A process for preparing 1-aminoanthraquinone, comprising the steps of: A. reacting o-chloromethylphenylisocyanate with at least an equivalent amount of benzene in anhydrous hydrofluoric acid at a temperature of about -10° to 200° C to form the lactam of 2-amino-diphenylmethane-2'-carboxylic acid, B. saponifying the lactam of 2-amino-diphenylmethane-2'-carboxylic acid with aqueous alkali at a temperature above about 100° C to form the 2-amino-diphenylmethane-2'-carboxylic acid, C. contacting the 2-amino-diphenylmethane-2'-carboxylic acid with an acid condensation agent, thereby to convert the carboxylic acid to 4-amino-anthrone, and D. contacting the 4-aminoanthrone with an oxidizing agent in an acid or alkaline medium, thereby to convert the aminoanthrone to 1-aminoanthraquinone. Special conditions are also recited for carrying out the individual steps to obtain high yields.
- -
-
-