Conversion of Ketone Enol Esters to β-Diketones by Intramolecular Thermal Rearrangement and by Intermolecular Acylations using Boron Fluoride

Young, Frank G.; Frostick, Frederick C.; Sanderson, James J.; Hauser, Charles R.

doi:10.1021/ja01164a088

Cited by 52 publications

(12 citation statements)

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“…In a similar procedure, (a) iodobutane and 2,4-pentanedione gave 3-n-butyl-2,4-pentanedione as a light yellow oil, 28%, bp 208°C (Ref. [27] bp 104-106"C/ 20 mm) and (b) isopropyl iodide and 2,4-pentanedione gave 3-isopropyl-2,4-pentanedione as a light yellow oil, 40%, bp 182°C (Ref. [28] bp 94"C/45 mm).…”

Section: Methodsmentioning

confidence: 99%

Pyrromethene–BF₂ complexes as laser dyes: 2

Boyer

Haag

Sathyamoorthi

et al. 1993

Heteroatom Chemistry

173

102

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Pyrromethene–BF2 complexes (P–BF2) 7 were obtained from α‐unsubstituted pyrroles 5 by acylation and condensation to give intermediate pyrromethene hydrohalides 6 followed by treatment with boron trifluoride etherate. Conversion of ethyl α‐pyrrolecarboxylates 4 to α‐unsubstituted pyrroles 5 was brought about by thermolysis in phosphoric acid at 160°C, or by saponification followed by decarboxylation in ethanolamine at 180°C, or as unisolated intermediates in the conversion of esters 4 to pyrromethene hydrobromides 6 by heating in a mixture of formic and hydrobromic acids. Addition of hydrogen cyanide followed by dehydrogenation by treatment with bromine converted 3,5,3′,5′‐tetramethyl‐4,4′‐diethylpyrromethene hydrobromide 9 to 3,5,‐3′,5′‐tetramethyl‐4,4′‐diethyl‐6‐cyanopyrromethene hydrobromide 6bb, confirmed by the further conversion to 1,3,5,7‐tetramethyl‐2,6‐diethyl‐8‐cyanopyrromethene–BF2 complex 7bb on treatment with boron trifluoride etherate. An alternation effect in the relative efficiency (RE) of laser activity in 1,3,5,7,8‐pentamethyl‐2,6‐di‐n‐alkylpyrromethene–BF2 dyes depended on the number of methylene units in the n‐alkyl substituent, ‐(CH2)nH, to give RE ≥ 100 when n = 0,2,4 and RE 65, 85 when n = 1,3. (The RE 100 was arbitrarily assigned to the dye rhodamine 6G). The absence of fluorescence and laser activity in 1,3,5,7‐tetramethyl‐2,6‐diethyl‐8‐isopropylpyrromethene–BF2 complex 7p and a markedly diminished fluorescence quantum yield (Φ 0.23) and lack of laser activity in 1,3,5,7‐tetramethyl‐2,6‐diethyl‐8‐cyclohexylpyrromethene–BF2 complex 7q were attributed to molecular nonplanarity brought about by the steric interference between each of the two bulky 8‐substituents with the 1,7‐dimethyl substituents. An atypically low RE 20 for a peralkylated dye without steric interference was observed for 1,2,6,7‐bistrimethylene‐3,5,8‐trimethylpyrromethene–BF2 complex 7j. Comparisons with peralkylated dyes revealed a major reduction in RE 0–40 for the six dyes 7u–z lacking substitution at the 8‐position. Low laser activity RE was brought about by functional group (polar) substitution in the 2,6‐diphenyl derivative 7I, RE 20, and the 2,6‐diacetamido derivative 7m, RE 5, of 1,3,5,7,8‐pentamethylpyrromethene–BF2 complex (PMP–BF2) 7a and in 1,7‐dimethoxy‐2,3,5,6,8‐pentamethylpyrromethene–BF2 complex 7n, RE 30. Diethyl 1,3,5,7‐tetramethyl‐8‐cyanopyrromethene‐2,6‐dicarboxylate–BF2 complex, 7aa, and 1,3,5,7‐tetramethyl‐2,6‐diethyl‐8‐cyanopyrromethene–BF2 complex, 7bb, offered examples of P–BF2 dyes with electron withdrawing substituents at the 8‐position. The dye 7aa, λlas 617 nm, showed nearly twice the power efficiency that was obtained from rhodamine B, λlas 611 nm.

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Section: Methodsmentioning

confidence: 99%

Pyrromethene–BF₂ complexes as laser dyes: 2

Boyer

Haag

Sathyamoorthi

et al. 1993

Heteroatom Chemistry

173

102

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“…7 (1 983) -Nr. 229 [16] Bei der Thermolyse von 11 bei 580" entstand hauptsachlich (lo), 63 (20). 55 (13), 54 (X), 53 (100, H C S -C O ) , 52 (29), 44 (20).…”

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Butatrien durch Thermolyse von Propiolsäure‐(2‐propinyl)ester

Bilinski

Dreiding

Hollenstein

1983

Helvetica Chimica Acta

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SummaryFlow thermolysis of 2-propynyl propiolate (5) at 580" afforded butatriene (6) (ca. 50%) and, as by-products, 4-methylene-2-cyclobuten-1 -one (7), 2-ethynylpropenal (€9, l-penten-4-yn-3-one (9), 4-penten-2-ynal (10) (total ca. 10 %), along with some propynal, acetylene, CO, and CO. In the same way, propiolic acid (1,1-D2)-2-propynyl propiolate (11) led to (1,l-DJ-butatriene (12) and a little 4-((D,)rnethylene)-2-~yclobuten-1-one (13). A mechanism is proposed for the transformation of 5 into 6 and of 11 into 12, which also accounts for the formation of 7, 8, 9 and 10, as well as 13. The position of one of the published I3C-NMR signals of butatriene (6) must be revised. Thermolysis of methyl-(1) and ethyl propiolate (2) resulted in small yields of 2-buten-4-olide (3) and 2-penten-4-olide (4).Auf der Suche nach Analogien zur a-Alkinon-Cyclisierung (A + C) [ J befassten wir uns mit der thermischen Umlagerung von Propiolsaureestern (B + D) (Schema I ) .Wahrend aus Propiolsaure-methyl-(1) und -8thylester (2) bei 600", wie erwartet, Lactone 3 bzw. 4 (Schema 2), allerdings in nur 6% bzw. 8% Ausbeuten entstanden (s. IS. Oktoher, 1982.

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“…The solvent was evaporated in vacuo, and the crude product was passed through a short column using hexane as eluant, to get 141.7 mg (67% yield) of the acetate. Under comparable conditions, reaction with isopropenyl acetate was found to proceed to ~ 40% conversion in 4 h. 1 H NMR (300 MHz, CDCl 3 ) inter alia δ 2.90 (dd, J = 6, 6 Hz, 1 H), 4.09 (ABX, υ A = 4.22, υ B = 3.96, J AB = 12 Hz, J AX = 6 Hz, J BX = 6 Hz, 2 H), 5.00 (m, 1 H); 13…”

Section: Reactions Listed In Equations 2-11mentioning

confidence: 89%

“…A mixture of (R)-Phenylglycine methyl ester (166.7 mg; 1 mmol) and isopropenyl acetate (1mL, 9.1 mmol) was stirred for 24 h at room temperature without any catalysts, the low boiling components were removed on the pump and the product was analyzed by GC and NMR. 1…”

Section: (R)-n-acetyl Phenylglycine Methyl Ester (Eq 8)mentioning

confidence: 99%

Metal-Catalyzed Acyl Transfer Reactions of Enol Esters: Role of Y₅(OⁱPr)₁₃O and (thd)₂Y(OⁱPr) as Transesterification Catalysts

and

RajanBabu

2000

Org. Lett.

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Primary and secondary alcohols react with vinyl or isopropenyl acetate at room temperature in the presence of catalytic amounts (0.05-1 mol %) of Y5(OiPr)13O to give the corresponding esters. In selected cases, the yttrium catalyst promotes the selective O-acylation of amino alcohols without the formation of the amide. Enol esters also react with alpha-amino acid esters in the absence of a catalyst, at room temperature, to give the corresponding amides.

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Conversion of Ketone Enol Esters to β-Diketones by Intramolecular Thermal Rearrangement and by Intermolecular Acylations using Boron Fluoride

Cited by 52 publications

References 1 publication

Pyrromethene–BF₂ complexes as laser dyes: 2

Pyrromethene–BF₂ complexes as laser dyes: 2

Butatrien durch Thermolyse von Propiolsäure‐(2‐propinyl)ester

Metal-Catalyzed Acyl Transfer Reactions of Enol Esters: Role of Y₅(OⁱPr)₁₃O and (thd)₂Y(OⁱPr) as Transesterification Catalysts

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Conversion of Ketone Enol Esters to β-Diketones by Intramolecular Thermal Rearrangement and by Intermolecular Acylations using Boron Fluoride

Cited by 52 publications

References 1 publication

Pyrromethene–BF2 complexes as laser dyes: 2

Pyrromethene–BF2 complexes as laser dyes: 2

Butatrien durch Thermolyse von Propiolsäure‐(2‐propinyl)ester

Metal-Catalyzed Acyl Transfer Reactions of Enol Esters: Role of Y5(OiPr)13O and (thd)2Y(OiPr) as Transesterification Catalysts

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Pyrromethene–BF₂ complexes as laser dyes: 2

Pyrromethene–BF₂ complexes as laser dyes: 2

Metal-Catalyzed Acyl Transfer Reactions of Enol Esters: Role of Y₅(OⁱPr)₁₃O and (thd)₂Y(OⁱPr) as Transesterification Catalysts