A directive effect of heterofunctions in cyclocondensation reactions of acetylenylquinones with hydrazine

Acetylenic derivatives of quinones

“…The replacement of the arylethynyl substituent in perialkynyl-1,4-naphthoquinones by a g-hydroxyalkynyl group changes the regioselectivity of condensation. 28,97 Under the same conditions, the reactions of 3-diethylamino-5-(3-hydroxyalkyn-1-yl)-1,4-naphthoquinones 150 with NH 2 NH 2 . H 2 O, unlike those of 5-arylethynyl derivatives 146, lead to the closure of the seven-membered diazepine ring (analogously to the reactions of peri-alkynylanthraquinones).…”

“…2-Alkynyl-1-chloroanthraquinones 155, in which the halogen atom has high nucleofugic lability, are readily condensed with NH 2 NH 2 on heating in pyridine. 94,97 Under these conditions, the reactions of quinones bearing hydrocarbon (Alk or Ar) acetylenic substituents can follow two pathways with the pyrazole-ring closure involving either the carbonyl group of the quinoid ring (compound 156) or the triple bond (compound 157). The regioselectivity of the reaction depends on the nature of the substituent in the starting alkynylquinone.…”

Synthesis of sulfur-containing heterocyclic compounds by cyclocondensation of acetylenic derivatives of anthraquinone with sodium sulfide

“…The crude product was chromatographed on silica gel in a benzene-ether mixture to yield 1.84 g (84%) of 1-chloro-2-(3-hydroxy-3-methylbutynyl)anthraquinone 1c; 17 …”

“…Earlier we reported the synthesis of a number of condensed N-and O-heterocyclic quinoid systems based on acetylenic derivatives of quinones as key precursors. [9][10][11][12][13][14][15][16][17][18] One would expect that the same "acetylenic" approach will turn out to be fruitful for the construction of an anthrathiophene system as well. Recently, a method for synthesis of substituted benzo [b]thiophenes by cyclization of orthomethylthio-and ortho-benzylthio(alkynyl)benzenes under the action of electrophilic agents was elaborated.…”

A Simple Synthesis of Angular Anthrathiophenediones via Acetylenic Derivatives of Anthraquinone

“…Earlier, we reported the synthesis of condensed quinoid structures including pyrrole, furan, pyridine, pyridazine, pyrazole, pyran and diazepin rings, which was based on acetylenic derivatives of anthraquinone and naphthoquinone as key intermediates. [7][8][9][10][11][12] In this work we used the same approach for the synthesis of an anthrathiophenedione system. Recently, a method for the synthesis of substituted benzo[b]thiophenes by cyclization of ortho-(methylthio)alkynyl-and ortho-(benzylthio)alkynylbenzenes under the action of electrophilic agents was elaborated.…”