Pyrrolidine-2,4-diones acids

Moffett [179] determined chromium in seawater by Zeeman corrected graphite tube atomisation atomic absorption spectrometry. The chromium is first complexed with a pentan-2,4 dione solution of ammonium 1 pyrrolidine carbodithioc acid, then this complex extracted from the water with a ketonic solvent such as methyl isobutyl ketone, 4-methylpentan-2-one or diisobutyl ketone. 

Wittig-Smiles reaction.l The reaction of a triarylmethylphosphonium halide and a base with an a-keto dicarboxylic acid halide imide such as 1 results in a Wittig reaction followed by a Smiles rearrangement to provide a pyrrolidine dione... 

H-Pyrrole-2,5-dione, 1,T-(phenylene) bis-. See m-Phenylenedimaleimide IH-Pyrrole, 1-(2-furanylmethyl)- Pyrrole, 1-furfuryl-. See 1-Furfuryl-1H-pyrrole 2-Pyrrolidine carboxylic acid Pyrrolidine-2-carboxylic acid. SeeL-Proline 2,5-Pyrrolidinedione. See Succinimide... 

Hunig and Salzwedel (20) report that the acylation of the pyrrolidine enamine of 3-methylcyclohexanone with propionylchloride followed by the hydrolysis and the base cleavage of the resulting dione isomers (71) and (72) and subsequent reduction of the keto groups gave a 3 7 mixture of the carboxylic acids (73 and 74), respectively. Vig et al. (39), however, found o o o o... 

FIGURE 7.23 Decomposition of a Boc-amino-acid /V-carboxyanhydnde by tertiary amine. Two molecules combine with the release of two molecules of C02 to form a pyrrolidine-2,4-dione. 

Quinoxaline derivatives (36), and not the expected sydnones, were obtained from the Af-nitroso derivatives of 3-arylamino-l-aryl-pyrrolidine-2,5-diones (35). The precise nature of this rearrangement has not so far been determined.40 The derived quinoxaline-2,3-dicarboxylic acid mono-jV-arylamides (37) were obtained in 40-60% yield. The latter compounds were also made by the conventional reaction of quinoxaline 2,3-dicarboxylic anhydride and an amine.40... 

The three-component reaction of pyruvic acid, aldehydes and anilines can also yield pyrrolidine-2,3-dione [198], but in most cases the products of such multicomponent condensations are quinoline carboxylic acids identical to compounds obtained via the reaction of arylidenepyruvic acids [217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228]. 

Reduction of 2,2-dimethyl-cyclohexane-1,3-dione (50) with Baker s yeast gave alcohol (ee 98.3%) whose tetrahydropyranyl derivative on methoxycarbonylation produced (51) quantitatively. Michael addition of (51) with methyl vinyl ketone followed by heating the adduct under reflux with pyrrolidine in benzene yielded (52) in 85% yield as stereoisomeric mixture whose separation presented problems. In order to eliminate the complexity due to a chiral center in tetrahydropyranyl protective group, deprotection of (52) was achieved by treatment with p-toluenesulphonic acid in methanol. The product obtained was a mixture of the lactone (53) and hydroxy ester (54). Probably the stereoisomer of... 

Formation of an enamine radical cation 45 was proposed as the chain initiation step in the autooxidation of enamines and SchifFs bases of a,/ -unsaturated ketones to give unsaturated 1,4-diones37. Pyrrolidine enamine of 10-methyl-A1(9)-octal-2-one (44) reacts with oxygen at room temperature to produce, after acid hydrolysis, 10-methyl-A1 (9)-octalin-2,8-dione (47) in 20% yield. Addition of a catalytic amount of FeCl3, Cu(OAc)2 or CuCl2 causes a pronounced enhancement in the oxidation rate and increases the yield to 80-85% after 1 h. 

Alkyl isocyanides undergo a smooth reaction with isopropylidene Meldrum s acid 396 in the presence of pyrrole or indole to produce 1-alkyl-3,3-dimethyl-4-(l//-pyrrole-2-carbonyl)-pyrrolidine-2,5-diones 400 (Scheme 86) or 1-alkyl-4-(lf/-indole-3-carbonyl)-3,3-dimethyl-pyrrolidine-2,5-diones 401 (Equation 94) in good yields <2004S0989>. 

The final series of five procedures presents optimized preparations of a variety of useful organic compounds. The first procedure in this group describes the preparation of 3-BROMO-2(H)-PYRAN-2-ONE, a heterodiene useful for (4+2] cycloaddition reactions. An optimized large scale preparation of 1,3,5-CYCLOOCTATRIENE, another diene useful for [4+2] cycloaddition, is detailed from the readily available 1,5-cyclooctadiene. Previously, the availability of this material has depended on the commercial availability of cyclooctatetraene at reasonable cost. A simple large scale procedure for the preparation of 3-PYRROLINE is then presented via initial alkylation of hexamethylenetetramine with (Z)-1,4-dichloro-2-butene. This material serves as an intermediate for the preparation of 2,5-disubstituted pyrroles and pyrrolidines via heteroatom-directed metalation and alkylation of suitable derivatives. The preparation of extremely acid- and base-sensitive materials by use of the retro Diels-Alder reaction is illustrated in the preparation of 2-CYCLOHEXENE-1.4-DIONE, a useful reactive dienophile and substrate for photochemical [2+2] cycloadditions. Functionalized ferrocene derivatives... 

Acylation of tetramic aclds. This Lewis acid is generally superior to BFs etherate or SnCU for acylation of tetramic acids (pyrrolidine-2,4-diones), particularly when the acyl group is unsaturated. An example is shown in equation (I). 

In this reaction, the formation of two series of compounds is proposed because in the chromatographic separations of polypeptide pyrolysates, an additional peak is noticed for each 3-alkenyl-5-alkyl-pyrrolidin-2,4-dione. This second peak is assigned to the corresponding 2,4-dialkyl-3,5-diketopyrroline (position isomers are not possible when R2 and R3 are identical) [1]. The list of different compounds from these two classes that may be formed during laser irradiation of different mammalian tissues [13a] due to peptide (protein) pyrolysis and the amino acid pair that can generate them is given in Table 12.2.3. 

Heyl and Herr developed an efficient method for the conversion of A -androstene-3,17-dione into testosterone involving in the first step selective enamine formation at C3. The diketone was refluxed with 4 equivalents of pyrrolidine and a trace of p-toluenesulfonic acid under a water separator, and the reaction was stopped when 1 mole of water had been collected. With the C3 carbonyl function protected," the keto group at C17 could be reduced smoothly. Hydrolysis of the enamine group with a weakly acidic buffer afforded testosterone. 

EljN (1.52 g, 15 mmol) was added to cooled formic acid (0.69 g, 15 mmol) at — 20°C. Then 1-(aminobicycIo[n.l.0]alkyl)pyrrolidine-2,5-dione (5 mmol) was added at 20°C and the mixture was stirred for 5 h at 140°C. The amine was isolated by extraction of the cooled mixture at 20°C with pentane (3 X 20 mL) and purified by addition of 5% HCl (20 mL), removal of the pentane extract, basification of the aqueous layer with 5% KOH and extraction with pentane (3 x 20 mL). The pentane solution was washed with citrate buffer (pH = 3.75 or 4.5 see table above). Pure amine was obtained from the pentane solution by evaporation of the solvent and distillation of the residue in a Kugelrohr apparatus. 

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