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

Abstract

Reaction of vic-alkynylchloro-and vic-chloro-(1-oxoalk-2-ynyl)-anthraquinones with Na 2 S in ethanol, with short heating, has been shown to afford anthrathiophenediones and anthrathiopyrantriones, respectively, generally in good yields. Under the same conditions, 1-alkynylanthraquinones also undergo cyclocondensation to give anthra[2,1-b]thiophene-6,11-diones.

Microwave-assisted three-component coupling-addition-SNAr (CASNAR) sequences to annelated 4H-thiopyran-4-ones

“…Prior to our studies, only a few examples of S N Ar-Michael addition of hydrosulfide to alkynones had been reported. 20 Hence, the remaining methodological challenge is the development of a general rapid one-pot three-component coupling-addition-S N Ar (CASNAR) process.…”

Thiophene-Fused π-Systems from Diarylacetylenes and Elemental Sulfur

“…As thiophene-containing π-systems show high charge transport properties, they are widely used in organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and organic photovoltaics (OPVs) . Since thiophene-annulation reactions, the so-called thienannulations, can produce various thiophene-fused π-systems, a number of thienannulation reactions have been investigated. , In most cases, it is necessary to introduce two functional groups (e.g., halogen, alkynyl, or sulfur-containing groups) on the arenes prior to thienannulation (Figure , eqs 1 and 2) . Although several examples exist, in which only one functional group is required, e.g.…”

One-Pot Synthesis of 2-R-Naphtho[2,3-b]thiophene-4,9-diones via Cyclization of 2-(R-Ethynyl)-1,4-naphthoquinones with Na2S2O3

“…In addition, we suggest the in-place synthesis of 2-( R -ethynyl)-NQ during a one-pot process from commercially available 2-Br-NQ and alkynes. For comparison, the conversion of an alkyne substrates, for example, 1,3-enynes, 1,3-diynes, , or activated ethynylarenes, − into the corresponding thiophenes is usually accomplished by using sulfur reagents capable of generating a reactive trisulfur radical anion (S 3•– ) under alkaline conditions on heating up to 130 °C …”