3-dicarbonyl Compounds Research Articles

ChemInform Abstract: New Synthetic Methodologies Involving Electron Transfer Process

The following new synthetic methodologies involving electron transfer process have been developed. (1) Cleavage of the carbon-silicon bond : The carbon-silicon bonds in organopentafluorosilicates are cleaved by various oxidizing agents via initial electron transfer. The carbon-silicon bonds in allylsilanes and α-heteroatom substituted organosilicon compounds are also cleaved by electrochemical oxidation. (2) Indirect electrochemical oxidation using polymeric electron carrier such as poly (vinylpyridinium) bromide. (3) Cycloaddition of 1, 3-dicarbonyl compounds : The radical species generated by electrochemical oxidation of 1, 3-diketones adds to the olefin to give the formal [3 + 2] cycloadducts, dihydrofurans or tetrahydrofurans. In the presence of molecular oxygen the formal [2 + 2 + 2] cycloaddition of 1, 3-diketone, olefin and molecular oxygen takes place. The electroinitiated radical chain mechanism is proposed.

電子移動過程を基礎概念とする新しい有機合成

The following new synthetic methodologies involving electron transfer process have been developed. (1) Cleavage of the carbon-silicon bond : The carbon-silicon bonds in organopentafluorosilicates are cleaved by various oxidizing agents via initial electron transfer. The carbon-silicon bonds in allylsilanes and α-heteroatom substituted organosilicon compounds are also cleaved by electrochemical oxidation. (2) Indirect electrochemical oxidation using polymeric electron carrier such as poly (vinylpyridinium) bromide. (3) Cycloaddition of 1, 3-dicarbonyl compounds : The radical species generated by electrochemical oxidation of 1, 3-diketones adds to the olefin to give the formal [3 + 2] cycloadducts, dihydrofurans or tetrahydrofurans. In the presence of molecular oxygen the formal [2 + 2 + 2] cycloaddition of 1, 3-diketone, olefin and molecular oxygen takes place. The electroinitiated radical chain mechanism is proposed.

Reaction of triphenylphosphine radical cation with 1,3-dicarbonyl compounds: Electrochemical one-step preparation of dioxomethylenetriphenylphosphoranes.

Electrochemical oxidation of Ph3P (1) in MeCN in the presence of 1, 3-dicarbonyl compounds, R1COCH2COR2 (3), with HCIO4 as the supporting electrolyte resulted in the formation of the phosphonium salts, Ph3P+-CH(COR1)COR2 ClO4- (4), provieded that R1 and/or R2 is a phenyl group. On the other hand, electrolysis in CH2Cl2 with 2, 6-lutidinium perhlorate gave the phosphoranes, Ph3P=C(COR1)COR2 (5), directly from 1 and 3 in fair to excellent yields : in this case, R1 or R2 need not necessarily be a phenyl group. Thus, the electrolysis is shown to be a convenient method to perpare 5 in a single step. Plausible processes for the formation of 4 and 5 are proposed, involving the reaction of electrochemically generated Ph3P+·with the enol form of 3 as the keystep.

Ｈｙｐｅｒｖａｌｅｎｔ有機よう素化合物を活用する有機合成 けい素，すず化合物との反応

Iodosylbenzene activated by the coordination of Lewis acids to the oxygen atom reacts readily with a variety of organosilicon and tin compounds to produce the hypervalent organoiodine (III) species. Allyl- and vinyliodine (III) compounds are highly reactive and act as the species equivalent to allyl and vinyl cations, because iodine (III) at the hypervalent state is a good Ieaving group. Reaction of alkynyliodine (III) compounds with stable enolates of 1, 3-dicarbonyl compounds produces substituted cyclopentenes via the (1, 5) C-H insertion of alkylidene carbene intermediates. 1, 4-Fragmentation of γ-tributylstannyl alcohols using iodosylbenzene, BF3, and DCC gives rise to unsaturated carbonyl compounds. The fragmentation, combined with conjugated addition of Bu3SnLi and reduction or alkylation, offers an efficient procedure for the reductive and alkylative ring opening of cyclic vinyl ketones.

ChemInform Abstract: REACTION OF 2‐FUNCTIONALIZED PYRIDINIUM SALTS WITH 1,3‐DICARBONYL COMPOUNDS: SYNTHESIS OF INDOLIZINE DERIVATIVES

AbstractUnter den angegebenen Reaktionsbedingungen reagieren die Pyridinium‐Salze (I) mit den Methylen‐aktiven Verbindungen (II) zu den lndolizinen (III).

Reaction of 2-Functionalized Pyridinium Salts with 1, 3-Dicarbonyl Compounds: Synthesis of Indolizine Derivatives

Abstract A number of derivatives of indolizine ring system have been prepared by reaction of 1-substituted 2-methylthio-4, 6-diphenylpyridinium iodides with 1, 3-dicarbonyl compounds in basic medium.

ChemInform Abstract: REACTIVITY OF 2‐METHYLENE‐1,3‐DICARBONYL COMPOUNDS. SYNTHESES OF 2,2,3‐TRISUBSTITUTED‐3,4‐DIHYDRO‐2H‐PYRANO(3,2‐C)(1)BENZOPYRAN‐5‐ONES

AbstractDas Hydroxy‐cumarin (III) reagiert mit den Methylen‐β‐dicarbonylverbindungen (II) zu den Addukten (IV), die sauer regioselektiv aber nicht stereoselektiv zu den Pyrano‐benzopyranen (V) und (VI) cyclisiert werden.

Reactivity of 2-methylene-1,3-dicarbonyl compounds. Syntheses of 2,2,3-trisubstituted-3,4-dihydro-2H-pyrano(3,2-c)(1)benzopyran-5-ones.

Michael condensation of 2-methylsulfinylmethyl-1, 3-dicarbonyl compounds (3) or 2-methylene-1, 3-dicarbonyl compounds (4) with 4-hydroxycoumarin (5) at ambient temperature gave 2-[(4-hydroxycoumarin-3-yl)methyl]-1, 3-dicarbonyl compounds (6). Treatment of 6 with methanolic hydrogen chloride resulted in the regioselective formation of 2, 2, 3-trisubstituted-3, 4-dihydro-2H-pyrano[3, 2-c][1]benzopyran-5-ones.

マスクされた求電子性オキソエチレン等価体としての共役ニトロオレフィンの合成的利用

Conjugated nitroolefins were found to react with silyl enol ethers, ketene silyl acetals, and 2-monoalkyl-and 2-unsubstituted 1, 3-dicarbonyl compounds to give 1, 4-diones, γ-ketoesters, triones, and furans, respectively. 1-Nitro-1-phenylthiopropene, a new nitroolefin, was synthesized and has been developed as the reagent for 3-methylfuran synthesis. Some of these reactions have also been applied to the total synthesis of gymnomitrol, curzerenone, epicurzerenone, evodone, ligularone, and isoligularone.

ChemInform Abstract: REGIOSELECTIVE SULFENYLATION OF DIANIONS DERIVED FROM 1,3‐DICARBONYL COMPOUNDS

AbstractÜber die Dianionen (II) erhält man aus (I) die Phenylthioderivate (IV) und mit (V) ein Gemisch der isomeren Phenylthiocarbonsäureester (IVa) und (VI).

Regioselective sulfenylation of dianions derived from 1,3-dicarbonyl compounds.

Regioselective sulfenylations of dianions derived from 1, 3-dicarbonyl compounds were investigated with readily available sulfenylating agents such as diphenyl disulfide, phenyl benzenethiosulfonate, and phenylsulfenyl chloride, employing sodium hydride and butyl lithium or lithium diisopropylamide as bases. Sulfenylations of the dianions prepared from the β-ketoesters Ia, Ib and VI, the β-ketoamide Ic, and the 1, 3-diketones X and XIII with diphenyl disulfide afforded IIIa, IIIb, VIII, IIIc, XII, and XV, respectively, in fairly good yields.

Reactions of 2, 2-Dibromo-1, 3-dicarbonyl Compounds with Sodium Alkoxides

The reactions of diethyl dibromomalonate [1] and 1, 3-diphenyl-2, 2-dibromopropane-1, 3- dione [13] with various sodium alkoxides were studied. The reaction of [1] with sodium ethoxide gave diethyl diethoxymalonate, diethyl carbonate [2], bromoform [3], ethyl dibromoacetate [4] and diethyl bromomalonate [5] D as main products. The reaction of [1] with the disodium alkoxides of 1, 2-diols gave the carbonic esters of the 1, 2-diols, [2], [3], [4] and [5] as main products. In the reaction of [13] with sodium ethoxide, ethyl benzoate, mandelic acid [15] and benzoic acid [16] were produced as main products. Finally, in the reaction of [13] with the disodium alkoxide of a 1, 2-dial, di- and mono-benzoyl esters of the 1, 2-diol, [15] and [16] were produced as main products. From these results, it is concluded that in the reactions of [1] and [13] with alkoxide ions, the main reaction is an attack of alkoxide ions to the carbonyl carbon of the substrates, and the substitution of bromine by alkoxide ions occurs as a side reaction.

S-Butylation of Alkali-Metal Salts of 1, 3-Dicarbonyl Compounds

アセチルアセトンおよびアセト酢酸メチルアルカリ金属塩のs-ブチル化反応について, O-アルキル化とC-アルキル化の配向性におよぼす溶媒効果,対イオンの影響を検討した。 反応の経過にともなってC/O比が変化せず,ずっと一定であることから,C-ブチル化の両反応同一反応次数の競争反応であり,しかも両者ともにSN2型の反応であることが明らかにされた。C/O比がアセト酢酸メチルナトリウム塩の場合 48/52であるのに対し,アセチルアセトナートの場合 27/73 (DMSO中, 60°C)であることから,反応種は二つの等価な反応中心Oをもつエノラートアニオンであると結論された。

Synthesis of derivatives of pyrrolo[1, 2-?]pyrmidine

Continuing investigations in the field of the synthesis of condensed heterocyclic systems containing pyrrole and indole fragments ¦1–3¦, we have condensed of 2-aminopyrrole derivatives with various 1, 3-dicarbonyl compounds. The reaction took place at the boil in solutions in pyridine or acetic acid, and also without a solvent at 150–160° C, forming in a single stage derivatives of pyrrolo[1, 2-a]pyrimidine (I–III) and pyrrolo[2, 1-b]-tetrahydroquinazoline (IV–VI). The condensation of 2-aminopyrrole with acetoacetic and substituted acetoacetic esters led to 4-oxo derivatives of pyrrolo[1, 2-β]pyrimidine (VII and VIII).

Acylation of 1, 3-Dicarbonyl Compounds in Amine Bases

Acylation of 1, 3-Dicarbonyl Compounds in Amine Bases

Syntheses of Reductones. A New Method of Synthesizing 2-Acetoxy-1, 3-dicarbonyl Compounds

Abstract 2-Acetoxy-l, 3-dicarbonyl compounds were synthesized by two methods, one consisting of the condensation of 1, 3-dicarbonyl compounds with an electrophilic reagent, followed by acetoxylation. By this method three new compounds, ethyl 5-phenyl-2-acetoxy-3-oxopentanoate (XVII), ethyl 5, 5-diphenyl-5-hydroxy-2-acetoxy-3-oxopentanoate (XVIII), and ethyl 2-acetoxy-3-oxoheptanoate (XIX), were obtained. The other method consisted of the acetoxylation of 1, 3-dicarbonyl compounds, followed by condensation. By this method three other new compounds, 6-phenyl-6-hydroxy-3-acetoxy-2,4-dioxohexane (IV), 6-phenyl-6-hydroxy-3-acetoxy-2,4-dioxo-hexane (VIII), and 6-phenyl-3-acetoxy-2, 4, 6-trioxohexane (X), were obtained.

Studies on the Azaindolizine Compounds. X. Synthesis of 5, 7-Disubstituted Pyrazolo [1, 5-<I>a</I>] pyrimidines

Condensation of 1, 3-dicarbonyl compounds with 5-aminopyrazole (III) and its 3-carboxylic ester (X) was examined and several kinds of 5, 7-disubstituted pyrazolo [1, 5-a]-pyrimidines were obtained. It was observed by the infrared spectrum that the hydroxyl group at 5- and 7-positions of pyrazolo [1, 5-a] pyrimidine ring shows the lactam form in the neutral medium

Synthesis of Potential Anticancer Agents. VIII. 6-Phenylazo-s-triazolo [2, 3-α] pyrimidines.

Several 6-phenylazo-s-triazolo [2, 3-α] pyrimidine derivatives were synthesized by either of the following two methods : 1) Benzenediazonium salt was coupled with s-triazolo [2, 3-α] pyrimidine derivatives at 6-position, by which the effect of 5- and 7-positions in s-triazolo [2, 3-α] pyrimidine was clarified. 2) 2-Phenylazo-1, 3-dicarbonyl compounds were condensed with 5-amino-s-triazole (IX).

Synthesis of Potential Anticancer Agents. VII. 6-Nitro- and 6-Amino-s-triazolo [2, 3-α] pyrimidines.

By nitration of s-triazolo [2, 3-α] pyrimidine derivatives, four kinds of 6-nitro derivatives (Va, VIa, VIIa, and VIIIa) were obtained. These nitro compounds were converted to the corresponding 6-amino derivatives by catalytic reaction and the nature of the amino group at 6-position was examined. 2-Acetamido-1, 3-dicarbonyl compounds were condensed with 5-amino-s-triazole (IX) into 6-acetamido-s-triazolo [2, 3-α] pyrimidines (VIc, VIIc, and VIIIc), which were converted into the corresponding 6-amino derivatives by hydrolysis.

CCLXXXV.—The chemistry of 1 : 3-dicarbonyl compounds. Part I. The mechanism of the cyanoacetamide and cyanoacetic ester condensations

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