The CH-cyclization of alkynyl-9,10-anthraquinones 1 into thienoanthraquinones 2 is shown to be initiated by the neutral S₂ molecule and not by the sulfide anion as it is assumed in the existing model of CH-cyclization with the nucleophiolic substitution of H. The formation of S₂ takes place in the reaction medium due to the partial reduction of the substrate 1 by Na₂S into the corresponding anthrahydroquinone, which is inactive in the main reaction. We present a new cyclization mechanism with the key stage involving the electrophilic displacement of H, which results in the formation of the reaction product 2 and elimination of S. In the reaction medium atomic sulfur is transformed into S₂, which initiates the next cyclization act. This determines the chain nature of cyclization with the participation of S₂. Within this model, the route to increase the yield of target thienoanthraquinones is proposed through the introduction of a neutral quinone able to generate S₂ by means of easy reduction.

炔基-9,10-蒽醌的CH-环化1到thienoanthraquinones 2被示出为通过中性S为发起₂分子，不是如假定在CH-环化的现有模型的nucleophiolic取代的硫化物阴离子H. S ₂的形成在反应介质中发生，这是因为底物1被Na ₂ S部分还原成相应的蒽氢醌，而后者在主反应中没有活性。我们提出了一种新的环化机理，其关键阶段涉及H的亲电置换，这导致了反应产物2的形成。在反应介质中，原子硫被转化为S ₂，从而引发下一个环化作用。这决定了在S ₂的参与下环化的链性质。在该模型中，通过引入能够通过简单还原生成S ₂的中性醌，提出了提高目标硫代蒽蒽醌产率的途径。