Isomerization of Trimethyl α-Keto Trithioorthocarboxylates into α,α-Bis(methylthio) Thiolcarboxylates. A New Rearrangement of Synthetic Interest
摘要:
A study was made of the isomerization reaction of a great variety of trimethyl alpha-keto trithioorthocarboxylates to alpha,alpha-bis(methylthio) thiolcarboxylates, intermediates of high synthetic value for the synthesis of alpha-arylpropionic acids. The reaction was carried out In methylene chloride in the presence of catalytic amounts of trityl perchlorate or methanesulfonic acid and was complete in 2 h at rt. In most of the investigated cases the result was positive, the yields usually being greater than 90%. Also the reaction mechanism was subjected to an experimental study.
A study was made of the isomerization reaction of a great variety of trimethyl alpha-keto trithioorthocarboxylates to alpha,alpha-bis(methylthio) thiolcarboxylates, intermediates of high synthetic value for the synthesis of alpha-arylpropionic acids. The reaction was carried out In methylene chloride in the presence of catalytic amounts of trityl perchlorate or methanesulfonic acid and was complete in 2 h at rt. In most of the investigated cases the result was positive, the yields usually being greater than 90%. Also the reaction mechanism was subjected to an experimental study.
An Interesting Synthetic Application of S-Alkyl (Aryl)bis(alkylsulfanyl)thioacetates: General Procedure for the Preparation of (±)-α-Arylpropionic Acids
Reported here is a new procedure for the synthesis of α-arylpropionic acids 1 in the racemic form, starting from derivatives of aromatic carboxylic acids 2 (i.e., esters), via 1-aryl-2,2,2-tris(alkylsulfanyl)ethanones 4-6, S-alkyl (aryl)bis(alkylsulfanyl)thioacetates 7-9, S-alkyl α-aryl-α-(alkylsulfanyl)thiopropionates 10-12 and S-alkyl α-arylthiopropionates 13-15. Each stage takes place easily and