351186-41-9Relevant articles and documents
Triple Mode of Alkylation with Ethyl Bromodifluoroacetate: N, or O-Difluoromethylation, N-Ethylation and S-(ethoxycarbonyl)difluoromethylation
Polley, Arghya,Bairy, Gurupada,Das, Pritha,Jana, Ranjan
supporting information, p. 4161 - 4167 (2018/09/21)
In this report, we have explored a triple mode of chemical reactivity of ethyl bromodifluoroacetate. Typically, bromodifluoroacetic acid has been used as a difluorocarbene precursor for difluoromethylation of soft nucleophiles. Here we have disclosed nucleophilicity and base dependent divergent chemical reactivity of ethyl bromodifluoroacetate. It furnishes lithium hydroxide and cesium carbonate promoted difluoromethylation of tosyl-protected aniline and electron-deficient phenols respectively. Interestingly, switching the base from lithium hydroxide to 4-N,N-dimethylamino pyridine (DMAP) tosyl-protected anilines afforded the corresponding N-ethylation product. Whereas, highly nucleophilic thiophenols furnished the corresponding S-carboethoxydifluoromethylation product via a rapid SN2 attack to the bromine atom prior to the ester hydrolysis. This mechanistic divergence was established through several control experiments. It was revealed that difluoromethylation reaction proceeds through a tandem in situ ester hydrolysis/decarboxylative-debrominative difluorocarbene formation and subsequent trapping by the soft nucleophile-NHTs or electron-deficient phenolic ?OH groups. In the presence of DMAP the hydrolysis of the ester is perturbed instead a nucleophilic attack at the ethyl moiety provides the N-ethylation product. Hence, besides the development of a practical base-promoted N-difluoromethylation of amines and electron-deficient phenols, divergent reactivity pattern of inexpensive and user-friendly ethyl bromodifluoroacetate has been explored. (Figure presented.).
A Convenient Multigram Synthesis of DABSO Using Sodium Sulfite as SO2 Source
Van Mileghem, Seger,De Borggraeve, Wim M.
supporting information, p. 785 - 787 (2017/05/29)
A convenient synthesis of DABCO·(SO2)2 (abbreviated as DABSO) is reported. Using a two-chamber setup, sulfur dioxide is generated in one chamber and consumed in the other. This closed system overcomes safety issues related to working
Aminosulfonylation of aromatic amines, sulfur dioxide and hydrazines
Zheng, Danqing,Li, Ying,An, Yuanyuan,Wu, Jie
supporting information, p. 8886 - 8888 (2014/08/05)
A facile route to aryl N-aminosulfonamides under mild conditions is provided. The reaction of aromatic amines (including heteroaromatic amines), sulfur dioxide, and hydrazines proceeds efficiently with good functional group tolerance. The in situ generated diazonium ion is involved in the aminosulfonylation process. This journal is the Partner Organisations 2014.
