Cyclopentadienylsodium, reaction with

Cyclopentadienylsodium, reaction with dimethylformamide-dimethyl sulfate complex, 47, 53 1,3-Cyclopentanedione, 2-methyl-, 47, 83... 

To a stirred flask containing a suspension of 4.8 gm (0.2 mole) of sodium hydride in 50 ml of THF under a nitrogen atmosphere is added dropwise 13.3 gm (0.2 mole) of cyclopentadiene. In a separate flask are mixed 19.8 gm (0.2 mole) of A-methyl-2-pyrrolidone and 25.2 gm (0.2 mole) of dimethyl sulfate. (NOTE Separately A-methyl-2-pyrrolidone and dimethyl sulfate should be anhydrous and should be purified by distillation before reacting with each other to form the complex.) The latter mixture is heated for 20 min on a steam bath, cooled, and then added dropwise to the cyclopentadienylsodium solution at —5°C. After the addition, the reaction mixture is stirred for 2 hr, filtered, the filtrate concentrated, and the residue is obtained as a brown oil. On cooling, the brown oil solidifies and is recrystallized from cyclohexane to afford pale-yellow needles weighing 14.0 gm (50%), m.p. 100°-101°C. 

Both sodium and potassium salts are natural constituents of body tissues and fluids as Na+ and K+ ions, respectively, and are not themselves toxic at normal physiological levels. The oxides and hydroxides of both these metals are very caustic, corrosive substances that damage exposed tissue. Oxides are formed by the combustion of sodium and potassium organometallics, and hydroxides are produced by the reaction of the oxides with water or by direct reaction of the organometallics with water, as shown below for cyclopentadienylsodium ... 

Azaferrocene (206) has been prepared by the reaction of sodium pyrrole, cyclopentadienylsodium, and ferrous chloride,157 or better by the reaction of potassium pyrrole with cyclopentadienyliron dicarbonyl iodide.158 It has been found159 that dioxane is a better solvent than benzene for this latter reaction. This reaction has also been applied to 2,4- and 2,5-dimethylpyrrole,158 3-acetyl-2-methyl-and 3-acetyl-2,4-dimethylpyrrole,160 and 2-methylpyrrole.159 The 2-methylazaferrocene from this latter pyrrole has been resolved with (—)6,6 -dinitrodiphenic acid.159 A compound (207) believed to be an intermediate in the formation of azaferrocenes has been isolated.161... 

Starting from 1,3,2-dioxathiolane 2,2-dioxide (18) and organometallic compounds, (3-substituted ethyl sulfates of type (133 R=CH(C02Me), Ph, PhC=C) may be synthesized (72JHC891). Reaction of glyoxal sulfate (134) with cyclopentadienylsodium followed by treatment with triethylamine led to the fulvene (135) (72AG297) the lithium salt of phenalene reacts in a similar fashion (80MI43301). 

The efficient formation of cyclopentadienylsodium is of paramount importance for the entire reaction sequence. Variations in the yield of methyl 2,4-cyclopentadiene-l-acetate have been traced to the degree of efficiency in producing a fine sodium sand which is used to produce cyclo-pentadienylsodium. In the alkylation reaction of cyclopentadienylsodium with methyl bromoacetate, the entire process nust be carried out in an Inert dry atmosphere at -78°C. At higher temperatures, the desired product can undergo undesired dimerization and double bond migration side reactions. Methyl 2,4-cyclopentadiene-l-acetate, once formed, is used Immediately. 

The chloro-bridged 1,5-hexadiene complex [(CaHio)RhCl]2, m.p. 115°-117°C, has been prepared by reaction of the olefin with [(C2H4)2RhCl]2 in diethyl ether at room temperature (149). When reacted with cyclopentadienylsodium, this complex produces... 

Dialkyl and diaryl Ti and Zr derivatives (18) are somewhat less stable than their monosubstituted analogs. They are generally prepared by alkylation of the corresponding dichloro compounds (17 equation 1 1).i3,29,30 jjjg dichloro derivatives themselves can be prepared in turn by reaction of tetrachlorides with the required amount of organometallic species. For example, zirconocene dichloride is prepared by treating zirconium(IV) chloride with cyclopentadienylsodium. ... 

Cyclopentadienyl carbonyls of several transition metals have been reported during the last decade, and these compounds have been shown to undergo a variety of interesting reactions. Two general methods have been used to prepare these materials treatment of metal carbonyls with cyclopentadiene or cyclopentadienylsodium, and the reac-... 

The only known syntheses of cyclopentadienylvanadium tetracarbonyl, C6H6V(CO)4, are based on the reaction of bis(cyclopentadienyl)vanadium with carbon monoxide under pressure. The procedure given below is based on this reaction but avoids isolation of pyrophoric bis-(cyclopentadienyl)vanadium by direct carbonylation of the solution obtained from vanadium(III) chloride and cyclopentadienylsodium. 

Vanadium (IV) chloride may be substituted here, but a correspondingly larger quantity of cyclopentadienylsodium must be used and the halide must be diluted with benzene to avoid too vigorous a reaction. For an autoclave of the size specified, however, no more than 400 ml. of solvent should be used. Vanadium (IV) chloride has the disadvantage of being very corrosive and unstable. 

Later, Hallam and Pauson prepared [Fe(CO)a- (CeHs) sP 2] by heating triphenylphosphine in an autoclave with an equimolecular amount of [Fe(CO)2CeH6]2 or [FeCl(CO)2C5H5], or by treating [Fel2(CO)j (C.Hs)aP ] with cyclopentadienylsodium in tetrahydrofuran. Recently, Cotton and Parish obtained the phosphine derivatives by heating triphenylphosphine and iron pentacarbonyl in a Carius tube. It has been found possible to prepare both mono- and diphosphine derivatives, as well as the corresponding arsines and stibines, much more simply by reaction in an appropriate solvent. ... 

The other syntheses of organochromium compounds are the reactions of chromium chloride with organoalkali metal compounds. For example, chromocene (bis-(r/ -cyclopentdienyl)chromium) is easily prepared in high yield by the reaction of chromium chloride with cyclopentadienylsodium in tetrahydrofuran as shown in eq. (13.23) [15,35]. 

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