Catalyst-free esterification of alcohols using 2-acyl-4,5-dichloropyridazinones under microwave conditions

Efficient Transfer of Chelating Amides into Different Types of Esters and Lactones

“…Isopropyl Benzoate (25a): 22 Synthesised according to General Procedure B. Purification by column chromatography (silica gel; CH 2 Cl 2 ) to give 25a (0.59 g, 3.60 mmol, 88 %) as a colourless liquid. 1 H NMR (400 MHz, CDCl 3 ): δ = 1.36 (s, 3 H, C H 3 ), 1.37 (s, 3 H, C H 3 ), 5.25 [sept, J = 6.3 Hz, 1 H, OC H (CH 3 ) 2 ], 7.40–7.45 (m, 2 H, ArH), 7.51–7.56 (m, 1 H, ArH), 8.02–8.06 (m, 2 H, ArH) ppm.…”

Recent Progress in the Chemistry of Pyridazinones for Functional Group Transformations

“…The tautomerization depends on the solvent’s dielectric constant and the electronic structure (e.g., the electron-donating vs electron-withdrawing groups) of substituents on the pyidazin-3­(2 H )-one. Since pyridazin-3­(2 H )-one readily forms the stable anion, stabilized by the resonance, it could act as a good leaving group. − Pyridazin-3­(2 H )-ones are also the ambient anions under basic conditions. , The regioselectivity of their N - and O -alkylations depends on the nature of the base, the structure of alkyl halide, the substituents on the heterocycle, and the reaction conditions such as temperature and solvent. , Pyridazin-3­(2 H )-ones can be easily removed and isolated for reuse during synthetic processes.…”

“…The substrate scope of 2-acylpyridazinones for acylation is not limited to amines; this reaction could be exploited for acylation of alcohols. Kim et al , described catalyst-free esterification of alcohols with 2-acyl-4,5-dichloropyrdazin-3­(2 H )-ones 3 under microwave or reflux conditions. Reaction of aliphatic and aromatic alcohols with 3 gives the corresponding esters in good to excellent yields (Scheme a).…”

Stereoselective and regioselective synthesis of $N$-substituted methyl 2-((azolyl)methyl)-3-arylacrylates from Baylis--Hillman acetates

“…14,15 * Correspondence: ilcelik@anadolu.edu.tr N -Acylazoles, which are effective acylating agents, are among the useful synthetic auxiliaries derived from these ring systems. They show great potential in organic synthesis as activated carboxylic acid derivatives to prepare amides, 18,19 esters, 18,20,21 thioesters, 18,21 ketones, 22,23 and some useful heterocycles. 24,25 Because there are few methods for the synthesis of N -substituted azole acrylates and the present methods have some drawbacks, herein we aimed to develop a more general method to synthesize N -substituted derivatives of imidazole, benzimidazole, and benzotriazole from the reaction between N -acylazoles and Baylis-Hillman adducts.…”