Herstellung und Reaktionen von 1‐Aryl‐3‐hydroxy‐3‐methyl‐2,5‐pyrrolidindionen

Abstract

Preparation and Reaction of l-Aryl-3-hydroxy-3-methyl-2,5-pyrrolidhedionesThe acetoacetamides 1 react with potassium cyanide to give the N-substituted 3-hydroxy-3-methyl-2,5-pyrrolidinediones 2. The unsubstituted 3-hydroxy-3-methyl-2,5-pyrrolidindione 14 is obtained by saponification of the 2-arylimino-3-hydroxy-3-methyl-5-pyrrolidinones 13, which are obtainable in the same reaction under somewhat modified conditions. These reactions are also observed with other P-ketocarboxamides, for example 18; their mechanisms are discussed. The 3-hydroxy-3-methyl-2,5-pyrrolidinediones 2 react with isocyanates to form the urethanes 21 and with thionyl chloride to give the 3-chloro-3-methyl-2,5-pyrrolidinediones 22. The latter easily eliminate hydrogen chloride to yield the 3-methyl-3-pyrroline-2,s-diones 23. Their hydrogenation, bromination, nitration, and reaction with cyclopentadiene are described.

Use of the N–O Bonds in N-Mesyloxyamides and N-Mesyloxyimides To Gain Access to 5-Alkoxy-3,4-dialkyloxazol-2-ones and 3-Hetero-Substituted Succinimides: A Combined Experimental and Theoretical Study

“…H NMR (400 MHz, CDCl 3 ):  = 8.48 (bs, 1 H, NH), 7.43-7.37 (m, 5 H, Ar-H), 3.23 (d, J = 18.4 Hz, 1 H, CHHCO), 3.10 (d, J = 18.4 Hz, 1 H, CHHCO). HRMS (ESI): m/z calcd for [C 10 H 8 NO 3 ] -: 190.0504; found: 190.0503.The analytical data are in agreement with the literature 32. …”

“…As already reported, 20b easily forms maleimide 18 with elimination of H 2 O, which is also found here as the cause of its low stability. 32 It is not yet possible to say at this point by which mechanism the reaction shown actually takes place. DFT calculations indicate that the postulated concerted [3,3] mesyloxy rearrangement is not probable because no corresponding transition state could be found.…”

“…As already reported, 20b easily forms maleimide 18 with elimination of H 2 O, which is also found here as the cause of its low stability. 32…”

Pyrrolidinetrione Derivatives: Synthesis And Applications in Heterocyclic Chemistry

“…Synthesis of these compounds was performed by chance during multi-step processes leading to bioactive pyrrolidine-2,5-diones. 45 Various studies indicate that these compounds exist essentially in the entirely enolized form 41 (Figure 8, Scheme 13). 45,46 Scheme 13…”

Gold(I)/Copper(II)‐Cocatalyzed Tandem Cyclization/Semipinacol Reaction: Construction of 6‐Aza/Oxa‐Spiro[4.5]decane Skeletons and Formal Synthesis of (±)‐Halichlorine

“…[23] Next, ozonolysis of the terminal olefin followed by dehydration provided amide 7 in a 36 % yield in two steps. [24] The high-pressure hydrogenation conditions successfully transformed compound 7 into compound 8 in an 88 % yield. A known three-step transformation method, to introduce the desired carboncarbon double bond and a configuration reversion of the C-14 methyl, was successfully achieved to give amide 9, although in a relatively low yield of 25 %.…”