Acetonitrile derivatives, reactions

The reactivity of carbonyl clusters can be enhanced substantially by the use of their activated derivatives which contain such labile ligands as acetonitrile, ethene, or cyclooctene. For example, it was the synthesis of acetonitrile derivatives Os3(CO)12 x(NCMe)x (x = 1,2)1 that spurred the development of the chemistry of this trinuclear cluster.2-4 In general, the reactions of the activated clusters occur under mild conditions and result in high selectivities and yields. 

A ring transformation takes place in the reaction of 3-mercapto- or 3-acylthio-3-isothiazo-line-5-thiones (331) with reactive alkynic compounds in boiling acetonitrile this reaction produces the 1,3-dithiole derivatives (332) in good yields (80JCS(P1)2693, 80H(14)785). 

Oxiranes yield oxazolines with nitriles in the presence of strong acids. The reaction proceeds with inversion, with complete stereospecificity. A new application of the Ritter reaction has been reported the opening of epimeric steroid-16,17-oxiranes in acidic medium with acetonitrile. The reactions of unsaturated hydroxynitriles formed from a-ethylenic oxiranes have been investigated. Numerous publications have appeared on the kinetics of reactions with carboxylic acids and their derivatives. ° ... 

The rearrangement could also be affected by the action of NaNa-INs on 2-iodocyclobutyl azides (254) in acetonitrile . The reaction of o-phenylenediamine with 2-bromocyclobutanone does not afford a fused dihydroquinoxaline derivative (257) as first claimed , but 2-cyclopropylbenzimidazole (258) is formed by way of a similar ring contraction (equation 175) . 

Diorgano tellurium oxides are reduced by hydrazine hydrate to diorgano tellurium compounds. The diorgano tellurium oxides are obtained as the primary products of the reactions of arenetellurinyl acetate or trifluoroacetates with olefins in chloroform, 1,2-dichloroethane, or acetonitrile as reaction media. When the olefin has a hydroxyl group in a j8-, 7-, or -position to the double bond, the addition of the tellurium compound to the double bond is followed by cyclization forming oxacycloalkane derivatives h... 

The reaction has been extended to a-silyl lactones and lactams. Other stabilizing groups have been demonstrated to be effective. For example, the Peterson reagent formed from bis(trimethylsilyl)propyne (357) and that formed from a-silyl acetonitrile derivatives (358) both give the (Z)-alkene as the predominant product (equation 84). ... 

An important synthesis for formamide acetals with bulky alkoxy groups or with -aryl substituents starts from the corresponding formamidinium salts or from bis(didkylamino)acetonitriles the reaction with alcoholic alkoxides furnishes the amide acetals (449 Scheme 83).7 -32.35 ju tjjg reaction of the azavinylogous formamidinium salt (450) with methanolic methoxide a mixture of -dimethylform-amide dimethyl acetal and its azavinylogous derivative is produced. 

The tungsten derivative W(f/ -C5H5)Me(CO)3 is much less reactive than the molybdenum analogue in the PPhj-promoted insertion of CO. While the molybdenum derivative [reaction (b)] reacts in acetonitrile at RT, the corresponding tungsten derivative does not react under the same conditions. For the reaction in acetonitrile, the rate constants (s ) are as follows W, (3.5 0.5) x 10 , 82°C Mo, (5 + 1) x 10 , SO C. No quantitative data are available for chromium, owing to the thermal lability of Cr((tf -CsH5)Me(CO)3, but qualitatively chromium resembles molybdenum. 

The ability of phosphines to act as both a metal oxidation states and as a 7r acceptor to relieve electron density from lower metal oxidation states explains, in part, the observation that diphosphines stabilize the +3, +1, and 0 oxidation states at the expense of the +2 oxidation state.870 Vanadium(II) diphosphine halides, [V(dmpe)2X2] (dmpe = dimethyl-dimethylphosphinoethane, X = Br or I), were prepared as side products in the synthesis of [XV(CO)2(dmpe)2].885 The structurally characterized diphosphino V11 tetrahydroborate complex, tra .s-[V(BH4)2(dmpe)2], (223) was synthesized via the reduction of similar vanadium(III) precursors.832 The reaction of a vanadium(II) chloride salt with dmpe afforded the tra s-[VCl2(dmpe)2] complex which can be alkylated with MeLi or MgMe2 to afford the organometallic trans-[V(Me)2(dm pcVJ compound, which in turn reacts with thiocyanate to form tnms -[V(NCS)2(dmpe)2].8 87 Acetonitrile or propionitrile readily displace the chlorides from trans- WCl2(dmpe)2] to form // tf/ ,v-[V( NCR)2(dmpc)2][BI>h4]2 (R = Me or Et) the acetonitrile derivative reacts with HCPh(S02CF3)2 in acetonitrile solvent to yield the hexaacetonitrile species [V(NCMe)6]2+.887... 

In acetonitrile all reactions of pyrrolidine addition exhibited AV values between -15 and -17cm3mol-1.262 However, upon decreasing the solvent polarity, AV became markedly more negative and a good correlation with the solvent parameter qv (i.e. the pressure derivative of q, the polarisability of the solvent) could be demonstrated. It was concluded that the addition of pyrrolidine followed a two-step process with a polar transition state leading to a zwitterionic intermediate. Addition of / ara-substituted anilines to a similar Fischer carbene complex in acetonitrile was characterised by more negative values of AV (-21 to -27cm3mol-1) than those for addition of pyrrolidine. 263 Second-order rate constants for the addition reaction exhibited an excellent correlation with the basicity of the aniline derivatives used. The trend in activation volumes could be correlated with an early or late transition state for the fast and slow addition reactions, respectively Scheme 12. 

The tert-butyl radical is a nucleophilic species and prefers to react via a transition state in which an electron has been transferred to the substrate. Apparently, the nucleophilicity of the tert-butyl radical becomes the dominant factor for the exoergic reactions of Table IV where an early transition state is involved. The reactions of nitronate anions seem to follow a similar rate profile. Very weakly basic anions such as CH(N02)2, C(NO)2)3, or fluorene=N02 fail to trap Me3C With R1 and R2 = H and C6H5 (2a = 1.1), a lower reactivity is observed than for the more basic CH2=N02- (2a = 0.98). However, as the electron-donating ability of the substituents increases further, the reactivity now decreases in a linear fashion with 2a giving p = 1.6 (r = 0.997) for H2C=N02-, MeCH=N02-, MeC(Ph) = N02 , and Me2C = N02-. The same effect seems to occur with acetonitrile derivatives where Ph2CCN- is 65 times more reactive than the more basic PhCHCN". 

Trisubstituted r-triazines 258 were synthesized using the trimerization reaction of phenyl acetonitrile derivative 257 with triflic acid (Equation 36) <2005BML1121>. 

Kinetics of the synthesis and aminolysis of 2,4-dinitrophenyl and 5-nitropyridine N-hydroxy oxime derivatives have been studied spectrophotometrically in acetonitrile. The reaction of several cholesterol-related oximes with 2-chloroethylamine in the presence of methoxide ion gives the corresponding oxime ethers DFT calculations indicate an oximate anion intermediate. ... 

Enantiomerically enriched Q, o -disubstituted phenylacetonitriles have been prepared from 2-alkyl-2-[2-(p-tolylsulflnyl)phenyl]acetonitriles by reaction with alkylating and acylating reagents under basic conditions. The use of enantiomerically pure )3-ketosulfoxides as nucleophiles in 1,4-additions to a,)3-unsaturated aldehydes catalysed by proline derivatives allows complete control of the two chiral centres to be simultaneously created in the reaction (Scheme 2). Because the catalyst and the sulfinyl group mainly control the configuration of the carbon atoms acting at the electrophile and nucleophile, respectively, the method allows the preparation of all four possible diastereoisomers in optically pure form. 

Nitrile enolates can also react with carbonyl derivatives such as oxalate, which serves as a carboxyl surrogate. Reaction of 2-phenylacetonitrile and diethyl oxalate, in the presence of sodium amide, gave 4.99. " Catalytic hydrogenation of the cyano group and hydrolysis led to ethyl 2-phenyl-3-aminopropanoate, 4.100. In this case also, the nitrile moiety was an amine surrogate. Other a-aryl acetonitrile derivatives... 

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