A Novel Base‐Solvent Controlled Chemoselective Azide Attack on an Ester Group versus Keto in Alkyl 3‐Substituted 3‐Oxopropanoates: Mechanistic Insights. Issue 21 (25th July 2017)

• Record Type: Journal Article
• Authors: Pokhodylo, Nazariy T.; Shyyka, Olga Ya.; Matiychuk, Vasyl S.; Obushak, Mykola D.; Pavlyuk, Volodymyr V.
• Is Part Of: ChemistrySelect. Volume 2:Issue 21(2017)
• Page Start: 5871
• Page End: 5876
• Publication Date: 2017-07-25
• Subjects: azides -- chemoselectivity -- cyclocondensation -- β-ketoesters -- 1, 2, 3-triazoles; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201700577
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: During the exploration of arylazides reactions with alkyl 3‐substituted‐3‐oxopropanoates under the Dimroth reaction conditions (MeONa‐MeOH) azide attack on ester group versus keto was found out in few examples yielding stable 3‐alkyl‐2‐diazo‐3‐oxo‐ N ‐(aryl)propanamides instead of obvious target 1‐aryl‐5‐alkyl‐1 H ‐1, 2, 3‐triazole‐4‐carboxylic acids. The formation of diazocompounds was observed in case of 3‐(4, 4‐diethoxymethyl)‐, isopropyl‐, cyclopropyl‐3‐oxopropanoate in the reaction with arylazides, especially, those containing electro‐withdrawing substituents. Influence of the base‐solvent system on diazo products yields was investigated and mechanistic insights of Dimroth reaction were discussed. Abstract : Attack of the azido group on the ester group instead of the keto‐ in β‐ketoesters was discovered and studied. Non‐classical, atypical, not described before formation of stable 3‐alkyl‐2‐diazo‐3‐oxo‐N‐(aryl)propanamides instead of obvious target 1‐aryl‐5‐alkyl‐1 H ‐1, 2, 3‐triazole‐4‐carboxylic acids was found. A number of unique 1‐aryl‐5‐alkyl‐1 H ‐1, 2, 3‐triazole‐4‐carboxylic were prepared from readily available starting materials in excellent yields.