Studies of heterocyclic compounds. Part VI. NN-dimethylthioform-amide: a new reagent in the Vilsmeier reaction

Abstract

NN-Dimethylthioformamide is a superior reagent in the Vilsmeier reaction. Examples of its use are described.

Kinetic and Mechanistic Study of Transition Metal Ion Catalyzed Vilsmeier–Haack Cyclization and Formylation Reactions with Acetanilides

“…Earlier publications from our laboratory [19,20] on solvent effect studies of VH reactions suggested a change in the nature of the reactive species on passing from high dielectric ACN medium to less dielectric DCE. In ACN (high dielectric media) participation of ion-pair species of VH adduct V and substrate was proposed in the slow step to give phosphorous oxychloromethyleniminium intermediate B followed by elimination of HCl.…”

“…A perusal of literature [17][18][19][20] coupled with the research published from our laboratory [19,20] suggest that VH reagent exists as covalent, ion-pair, and cationic forms of reactive species, in solution, as shown in structures I to V in DMF/ POCl 3 and V to X in DMF/SOCl 2 system:…”

“…[19,20] Kinetic Method Methodology to follow the progress of reaction and the kinetic data analysis is similar to the one reported by us earlier. [19,20] Aliquots of the reaction mixture were transferred into hot water as a function of time and kept a side for at least 2 h. During this period unreacted VH adduct hydrolyzes to give mixture of acids (HCl and H 2 SO 4 in the case of DMF/ SOCl 2 ; and HCl and H 3 PO 4 in the case of DMF/POCl 3 ). Acid content thus liberated is titrated with standard NaOH using Bromocresol green as indicator.…”

“…VH reactions with organic compounds in general and hydrocarbons with excess pi-electrons in particular undergo formylation very easily on synthetic scale. [15][16][17][18][19][20][21][22][23] During the past several years transition metal slats and complexes have received the attention of chemists and biochemists as catalysts in large array of chemical and biochemical reactions. This could be probably due to the reason that transition metals can both lend electrons to and take electrons from other molecules.…”

Rate Enhancements in the Acetylation and Benzoylation of Certain Aromatic Compounds with Vilsmeier-Haack Reagents Using Acetamide, Benzamide and Oxychlorides under Non-Conventional Conditions

“…VH reagents could be prepared form equimolar mixture of formamide or N, N'-dialkyl formamides such as N, N'-dimethyl formamide (DMF), N, N'-diethyl formamide (DEF), along with oxy halides such as POCl 3 and SOCl 2 at freezing temperatures. Recent reports on Vilsmeier-Haack (VH) reactions revealed that organic compounds in general and hydrocarbons with excess pi-electrons in particular undergo formylation very easily on synthetic scale [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. However, these reactions are known to afford acetyl derivatives when N, N'-dialkyl formamides are replaced by acetamide or N, N'-dialkyl acetamides such as N, N'-dimethyl acetamide (DMA) and N, N'-diethyl acetamide (DEA) in VH reagent.…”