16120-49-3

Upstream product

• 4636-16-2 iodoacetophenone 
• 91-56-5 indole-2,3-dione 
• 532-27-4 1-chloroacetophenone 
• 70-11-1 α-bromoacetophenone 
• 3486-31-5 isatin sodium salt 

Downstream Products

• 74588-82-2 2-benzoyl-1H-indole-3-carboxylic acid 
• 144294-91-7 3-hydroxy-2-(4-nitrophenyl)-4-oxo-1,4-dihydroquinoline 
• 1217043-16-7 2'-amino-4'-benzoyl-2'-methylspiro[indole-3,5'-[1,3]oxathiolane]-2(1H)-one 
• 859068-01-2 (2-oxo-indolin-3-yl)-phenyl-ethanedione 

Relevant academic research and scientific papers

Polyfunctional 4-quinolinones. Synthesis of 2-substituted 3-hydroxy-4-oxo-1,4-dihydroquinolines

We present here two new methods based on rearrangement reactions to obtain novel 2-substituted 3-hydroxy-4-oxo-1,4-dihydroquinolines, an important family of heterocycles with potential applications. Alkyl 3-hydroxy-4-oxo-1,4-dihydroquinoline-2-carboxylates were obtained by alkoxide promoted rearrangement of alkyl isatinacetates. A second synthetic route involves the alkoxide promoted reaction of both isatin and N-methylisatin, with alkylating agents having acidic methylenes. This reaction leads to the formation of spiroepoxyoxindoles via Darzens' condensation. When phenacyl bromides are used, the initially obtained benzoyl substituted spiroepoxyoxindoles were smoothly transformed into the corresponding 2-benzoyl-3-hydroxy-4-quinolinones with good to excellent yields.

Facile synthesis of functionalized spiro[indoline-3,2'-oxiran]-2-ones by Darzens reaction

A series of functionalized spiro[indoline-3,2'-oxiran]-2-ones was efficiently synthesized by Darzens reaction of phenacyl bromides with isatins both with N-alkyl groups and without N-substituent in the presence of potassium carbonate as a base catalyst. When two equivalents phenacyl bromides were used in the reaction, the N-substitution reaction of isatin also finished with the formation of spiro-oxirane-oxindoles.

Reaction of isatin with alkylating agents with acidic methylenes

The reaction of isatin (1) with different alkyl halides 2 and alkaline carbonates in aprotic polar solvents leads mainly to N-alkyl derivatives 3. The use of alkylating agents that have acidic methylenes leads to competitive formation of the corresponding epoxide 5. The formation of 5 is favored by low-polarity solvents at low temperatures and strong bases. Epoxides 5c, d obtained using NaEtOH/EtOH at 0-5 °C are transformed into the corresponding 4-quinolinones 6 at higher temperatures. The use of Ag2CO3 allows obtaining compounds 3 as major products, along with varying amounts of labile O-alkyl derivatives 4 and dimerization products.

Simple and efficient microwave assisted N-alkylation of isatin

We present herein the results of microwave promoted N-alkylations of isatin (1) with different alkyl, benzyl and functionalized alkyl halides. Reactions were carried out under different conditions, always employing methodologies compatible with MW assisted chemistry. Generation of isatin anion employing diverse bases and solvents or using the preformed isatin sodium salt was tested. The best results were achieved using K2CO3 or Cs 2CO3 and a few drops of N,N-dimethylformamide or N-methyl-2-pyrrolidinone. These reactions present noteworthy advantages over those carried out employing conventional heating.