Synthese von nitro‐ und aminosubstituierten Thiobenzamiden durch Thiolierungsreaktionen mit elementarem Schwefel unter milden Bedingungen

Abstract

Synthesis of Nitro‐ and Amino‐Substituted Thiobenzamides by Thiolation Reactions with Elemental Sulfur at Mild Conditions The Synthesis of thiobenzamides 2–7 by basecatalyzed thiolation of nitro‐benzyl‐halides (type 1), especially at low temperatures, and the selective synthesis of p‐ and m‐nitro‐thio‐benzamides (2, 3) or p‐and m‐amino‐thiobenzamides (5, 6), respectively, are described. o‐Nitro‐benzylhalides (→ 4, 7) are less reactive than p‐ and m‐nitro‐benzylhalides. The reaction of nitrobenzylhalides (type 1) with elemental sulfur and amines occuring at low temperatures to give 2–4 leads via structures of the type 11, 15 and 16.

A Domino Annulation Reaction under Willgerodt−Kindler Conditions

“…With the activating para -nitro group of 5g , the synthesis of the corresponding tricyclic hetarene 8g′ is successful, despite the reduction of the nitro group, which must have taken place after the nucleophilic cyclization. Indeed, under moderate reaction conditions (diluted with DMF as solvent and just 100 °C for 12 min), we were able to isolate the monocyclization product 10g with an intact nitro group. According to orientating experiments, this type of acetyl benzothiophenes can indeed be oxidatively cyclized under the rather harsh reaction conditions A.…”

Substituted 1,4,2-dithiazines: synthesis by ring expansion of 1,3-dithiolium cations, solution redox properties and X-ray crystal structures of a monocyclic and a bicyclic derivative

“…Surprisingly, the highest yield (14%) of compound 19, which is unsubstituted at C-5 and C-6, was obtained with 1 equivalent of iodine; 5 equivalents of iodine reduced the yield of 19 to only 6%. 1,4,2-Dithiazines lla-d, 22 and 23 are air-stable for at least several months at room temperature; derivatives 19-21 and 24, however, are substantially less stable, requiring storage at 0 "C; decomposition occurs at room temperature to yield numerous unidentified products (TLC evidence). The low isolated yield of 19 in the presence of an excess of iodine could be due to oxidation of the product by the halogen.…”