“…The heterocyclic α-diketones 7 and 8 were prepared according to literature procedures. 2,2,5,5-Tetramethylfuran-3,4(2H,5H)-dione 7 [56,57] was synthesized in 45 % overall yield by the mercuric acetate-catalyzed cyclization of 2,5-dimethyl-3-hexyne-2,5-diol in dilute aqueous sulfuric acid, [58][59][60] followed by oxidation of the resulting dihydrofuranone with selenium dioxide in dioxane. [61,62] 2,2,5,5-Tetramethylthiophene-3,4(2H,5H)-dione 8 [63] was obtained in 80 % yield by the reaction of 2,5-dibromo-2,5-dimethylhexane-3,4-dione with sodium sulfide in methanol.…”
The synthesis and extraction of americium(III) and europium(III) from aqueous nitric acid solutions by the new BTBP ligands 6,6'-bis (5,5,7,7-tetramethyl-5,7-dihydrofuro[3,4-e]-1,2,4-triazin-3-yl)-2,2'-bipyridine (Cy 5 -O-Me 4 -BTBP) and 6,6'-bis (5,5,7,7-tetramethyl-5,7-dihydrothieno[3,4-e]-1,2,4-triazin-3-yl)-2,2'-bipyridine (Cy 5 -S-Me 4 -BTBP) is described. The affinity for Am(III) and the selectivity for Am(III) over Eu(III) of Cy 5 -S-Me 4 -BTBP were generally higher than for Cy 5 -O-Me 4 -BTBP. For both ligands, the extraction of Am(III) and Eu(III) from 3 M HNO 3 into 3 mM organic solutions varied with the diluent used. The highest distribution ratios and separation factors observed were in cyclohexanone and 2-methylcyclohexanone, respectively. For Cy 5 -S-Me 4 -BTBP, there is a strong correlation between the distribution ratio for Am(III) and the permittivity of the diluent used. With 1-octanol as the diluent, low distribution ratios (D(Am) < 1) were observed for Cy 5 -S-Me 4 -BTBP although this ligand extracts Am(III) selectively (SF Am/Eu = 16-46 from 1-4 M HNO 3 ). For Cy 5 -S-Me 4 -BTBP, Am(III) is extracted as the disolvate. The distribution ratios for Am(III), and the separation factors for Am(III) over Eu(III) are both significantly higher for CyMe 4 -BTBP than they are for Cy 5 -O-Me 4 -BTBP and Cy 5 -S-Me 4 -BTBP in cyclohexanone. Changing the diluent from cyclohexanone to 2-methylcyclohexanone leads to a decrease in D(Am) but an increase in SF Am/Eu for Cy 5 -S-Me 4 -BTBP.
“…The heterocyclic α-diketones 7 and 8 were prepared according to literature procedures. 2,2,5,5-Tetramethylfuran-3,4(2H,5H)-dione 7 [56,57] was synthesized in 45 % overall yield by the mercuric acetate-catalyzed cyclization of 2,5-dimethyl-3-hexyne-2,5-diol in dilute aqueous sulfuric acid, [58][59][60] followed by oxidation of the resulting dihydrofuranone with selenium dioxide in dioxane. [61,62] 2,2,5,5-Tetramethylthiophene-3,4(2H,5H)-dione 8 [63] was obtained in 80 % yield by the reaction of 2,5-dibromo-2,5-dimethylhexane-3,4-dione with sodium sulfide in methanol.…”
The synthesis and extraction of americium(III) and europium(III) from aqueous nitric acid solutions by the new BTBP ligands 6,6'-bis (5,5,7,7-tetramethyl-5,7-dihydrofuro[3,4-e]-1,2,4-triazin-3-yl)-2,2'-bipyridine (Cy 5 -O-Me 4 -BTBP) and 6,6'-bis (5,5,7,7-tetramethyl-5,7-dihydrothieno[3,4-e]-1,2,4-triazin-3-yl)-2,2'-bipyridine (Cy 5 -S-Me 4 -BTBP) is described. The affinity for Am(III) and the selectivity for Am(III) over Eu(III) of Cy 5 -S-Me 4 -BTBP were generally higher than for Cy 5 -O-Me 4 -BTBP. For both ligands, the extraction of Am(III) and Eu(III) from 3 M HNO 3 into 3 mM organic solutions varied with the diluent used. The highest distribution ratios and separation factors observed were in cyclohexanone and 2-methylcyclohexanone, respectively. For Cy 5 -S-Me 4 -BTBP, there is a strong correlation between the distribution ratio for Am(III) and the permittivity of the diluent used. With 1-octanol as the diluent, low distribution ratios (D(Am) < 1) were observed for Cy 5 -S-Me 4 -BTBP although this ligand extracts Am(III) selectively (SF Am/Eu = 16-46 from 1-4 M HNO 3 ). For Cy 5 -S-Me 4 -BTBP, Am(III) is extracted as the disolvate. The distribution ratios for Am(III), and the separation factors for Am(III) over Eu(III) are both significantly higher for CyMe 4 -BTBP than they are for Cy 5 -O-Me 4 -BTBP and Cy 5 -S-Me 4 -BTBP in cyclohexanone. Changing the diluent from cyclohexanone to 2-methylcyclohexanone leads to a decrease in D(Am) but an increase in SF Am/Eu for Cy 5 -S-Me 4 -BTBP.
“…Another method, analogous to the one applied for the synthesis of azetidin-3-ones (vide supra), involved the lead(IV) acetate oxidation of 2,2,4,4-tetrasubstituted-3-hydroxyoxetane-3-carboxylic acids 205 (Scheme ). − 56 …”
Section: B2 Oxidation Reactionsmentioning
confidence: 99%
“…Treatment of 204 with stronger base resulted in 2,2,4,4-tetrasubstituted-3-hydroxyoxetane-3-carboxylic acid 205 via a benzylic acid type rearrangement. For the final conversion of the 3-hydroxyoxetane-3-carboxylic acid into the oxetan-3-one 206 , several methods (among which were pyrolysis, oxidation with NBS, oxidation with dilute potassium permanganate) proved to be unsuccessful . Only lead(IV) acetate seemed to be useful for this final transformation. − Of course, again, the scope of this reaction is limited due to the tetrasubstitution of the oxetane ring.…”
Section: B2 Oxidation Reactionsmentioning
confidence: 99%
“…The carboxylic acid 250 was cleaved further to α-hydroxycarboxylic acid 251 by hydrogen chloride, while hydrogen iodide in aqueous acetic acid gave a reductive cleavage to diphenylacetic acid 252 and diphenylmethane 253 . The reaction of tetramethyloxetan-3-one 249 (R = Me) with zinc in acetic anhydride resulted in the formation of α,α‘-diacetoxydiisopropyl ketone 255 and α-acetoxydiisopropyl ketone 256 …”
Section: C1 Ring Opening and Ring Expansion Of Oxetan-3-onesmentioning
confidence: 99%
“…141 Another method, analogous to the one applied for the synthesis of azetidin-3-ones (vide supra), involved the lead(IV) acetate oxidation of 2,2,4,4-tetrasubstituted-3-hydroxyoxetane-3-carboxylic acids 205 (Scheme 56). [143][144][145] Bromination of 2,2,5,5-tetramethyltetrahydro-3furanone 202 yielded the 4,4-dibromo derivative 203. 142 Synthesis of 2,2,5,5-tetramethyltetrahydrofuran-3,4-dione 204 has been achieved by base treatment of 203 142,143 or by direct oxidation of 202 with selenium dioxide in water.…”
I. Introduction 29 II. The Chemistry of Azetidin-3-ones 29 A. Structural Data 29 B. Synthetic Methods for Azetidin-3-ones 31 B.1. Carbonyl Group Generation in the Azetidine Ring 31 B.2. Intramolecular Cyclization Reactions 34 B.3. 1,3-Dipolar Cycloaddition Reactions 36 C. Chemical Properties of Azetidin-3-ones 37 C.1. Transformations of the Carbonyl Group 37 C.2. Condensation Reactions − Synthesis of 2-Benzylideneazetidin-3-ones 40 C.3. Ring Transformations of Azetidin-3-ones 40 C.4. Miscellaneous 41 III. The Chemistry of Oxetan-3-ones 42 A. Structural Data 42 B. Synthetic Methods for Oxetan-3-ones 43 B.1. Decomposition of Diazoketones 43 B.2. Oxidation Reactions 44 B.3. Intramolecular Displacement Reactions 46 B.4. Miscellaneous 47 C. Chemical Properties of Oxetan-3-ones 48 C.1. Ring Opening and Ring Expansion of Oxetan-3-ones 48 C.2. Transformations of the Carbonyl Group 49 IV. The Chemistry of Thietan-3-ones 50 A. Synthetic Methods for Thietan-3-ones 51 A.1. Synthesis from Acyclic Precursors 51 A.2. Synthesis by Ring Transformations 53 B. Chemical Properties of Thietan-3-ones 54 B.1. Transformations of the Carbonyl Group 55 B.2. Aldol Reactions 56 B.3. Ring Transformations 56 V. Acknowledgments 58 VI. References 58
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