55883-40-4

Upstream product

• 123-38-6 propionaldehyde 
• 74586-02-0 phenylnitrene anion radical 
• 630-19-3 pivalaldehyde 
• 75-07-0 acetaldehyde 
• 1197040-29-1 phenyl isocyanate 

Relevant academic research and scientific papers

Imidate Anions: Stereochemistry, Equilibrium, Nitrogen Inversion, and Comparison with Proton Exchange

Soluble imidate anions, especially formimidate anions, HC(O-)=NR, can be prepared by treating the amide with NaH or KH in THF or Me2SO.N-Phenylformimidate anion can also be prepared in hydroxylic solvents by treating the amide with excess NaOH.The imidate anions have been characterized by proton NMR.The E stereoisomer is generally more stable than the Z, but the E/Z equilibrium constant is strongly solvent dependent.The results are compared with previous studies of base catalyzed proton exchange.According to saturation-transfer measurements, the barrier to nitrogen inversion in these imidate anions is 19-23 kcal/mol.The imidate anions could be protonated by trifluoroethanol to regenerate the amide as a nonequilibrium E/Z mixture, which then returned to equilibrium at a measurable rate.

Chemistry of Isocyanides. Part 2. Nucleophilic Addition of Hydroxide to Aromatic Isocyanides in Aqueous Dimethyl Sulphoxide. Correlations of Rate with a Nucleophilicity Function

A range of aromatic isocyanides has been found to undergo nucleophilic addition of hydroxide in aqueous dimethyl sulphoxide (DMSO) over the composition range 0-98.67 molpercent DMSO.The rate of reaction increases as the aqueous content of the solutions is decreased.At compositions low in DMSO correlations of log kobs with H- + log aw are linear with slopes of 0.47-0.50, while at higher levels of DMSO correlations are also linear, but with slopes of 0.73-0.90.The results are discussed in terms of a solvent-induced switch from a concerted to a stepwise mechanism.An unusually enhanced reactivity of m-nitrophenyl isocyanide is observed and possible explanations for this are considered.

Mechanism of E/Z Stereoisomerization of Imidate Anions

Kinetics of E/Z stereoisomerization of N-arylformimidate anions, HC(O-)=NAr, in N-methylpropionamide solvent were determined by an NMR saturation-transfer method.A Hammett plot of the rate constans gives a slope ρ of +2.3 +/- 0.2 or +2.1 +/- 0.3.This value is very close to the ρ of 2.2 observed in similar imine stereoisomerizations know to proceed by nitrogen inversion.It is inconsistent with the ρ of 3.8 expected for stereoisomerization by C-N rotation.It is therefore concluded that E/Z stereoisomerization of imidate anions proceeds by nitrogen inversion, despite a high-level MO calculation that favored C-N rotation.

Gas-Phase Nucleophilic Reactivities of Phenylnitrene (PhN-*) and Sulfur Anion Radicals (S-/.) at sp3 and Carbonyl Carbon

The reactions of PhN-/. with a series of carbonyl-containing molecules (aldehydes, ketones, and esters) were shown to proceed via an addition/fragmentation mechanism, PhN-* + R2C=O -> -)R2> -> PhN=C(O-)R + *R, producing various acyl anilide anion products.In several cases, the tetrahedral intermediate anion radicals were observed as minor ions.The intrinsic reactivity of the carbonyl-containing molecules was aldehydes > ketones > esters, where similar R groups were involved.The overall exothermicities of these reactions did not appear to play the major role in determining the relative rates (krelC=O) for these reactions.From the reaction of PhN-* with cyclobutanone, a new type of anion radical, PhN=C(O-)CH2* (m/z 133) (+ C2H4) was produced; the loss of C2H4 was considered due to the ring strain in the ketone.With cyclopentanone, cyclohexanone, and cycloheptanone, the anion radicals PhN=C(O-)(CH2)n* (n = 4-6) were the exclusive product ions.PhN-* was shown to be a poor nucleophile in SN2 displacement reactions with CH3X molecules (X = Cl, Br, O2CCF3).S-* was shown to exhibit modest SN2 nucleophilicity with CH3Cl and CH3Br.The reactions of S-* with CF3CO2R proceed via both SN2 displacement and carbonyl addition/fragmentation mechanisms: with R = CH3, the anion products were 65percent CF3CO2- and 35percent CF3COS-; from R = C2H5, the product ions were 4percent CF3CO2- and 96percent CF3COS-.These data yield the ratio kCH3/kC2H5 = 16 for SN2 displacement by S-* at these alkyl groups.The reactions of PhN-* with CO2, COS, CS2, and O2 are also reported.The reaction of PhN-* with CS2 to produce S-* as a major channel was used as the source of this atomic anion radical.In several reactions occuring at nearly the collison limit, selectivity was observed for (a) which of two reaction centers were attacked to give products and (b) which of two mechanisms would be dominant in the overall reaction.