Heterocyclic Iodides Research Articles

The Halogen-Samarium Exchange Reaction: Synthetic Applications and Kinetics.

Fast I/Sm and Br/Sm exchanges take place when various aromatic or heterocyclic iodides and bromides are treated with nBu2 SmCl⋅4 LiCl and nBu3 Sm⋅5 LiCl, respectively. The resulting organosamarium reagents were efficiently quenched with aldehydes, ketones, and imines. Also, they undergo acylations when treated with N,N-dimethylamides leading to ketones. The rate of the Br/Sm exchange for a typical aryl bromide was determined and found to be 8.5×105 faster than the Br/Mg exchange, indicating that the rate of a metal-exchange is related to the ionic character of the carbon-metal bond and to the metal electronegativity.

ChemInform Abstract: Palladium‐Catalyzed Oxalyl Amide‐Directed γ‐Arylation of Aliphatic Amines.

A method for palladium-catalyzed oxalyl amide-directed arylation of α-unsubstituted aliphatic amines with aryl iodides has been developed. A wide variety of aryl iodides are tolerated in this transformation, affording various γ-arylpropylamine derivatives. Heterocyclic iodides can also be competent reagents in this γ-C(sp(3))-H bonds transformation.

ChemInform Abstract: Metal‐Free Synthesis of N‐Fused Heterocyclic Iodides via C—H Functionalization Mediated by tert‐Butylhydroperoxide.

Direct, regioselective and metal-free synthesis of fused N-heterocyclic iodides is reported. This regioselective C–H functionalization is mediated by tert-butylhydroperoxide (TBHP), via dual activation of molecular iodine and a heterocyclic substrate, resulting in the in situ generation of electrophilic iodine species (I+), and free radical(s) tBuO˙ or tBuOO˙, driving the iodination reaction.

Palladium-Catalyzed Oxalyl Amide-Directed γ-Arylation of Aliphatic Amines.

A method for palladium-catalyzed oxalyl amide-directed arylation of α-unsubstituted aliphatic amines with aryl iodides has been developed. A wide variety of aryl iodides are tolerated in this transformation, affording various γ-arylpropylamine derivatives. Heterocyclic iodides can also be competent reagents in this γ-C(sp(3))-H bonds transformation.

Metal-free synthesis of N-fused heterocyclic iodides via C-H functionalization mediated by tert-butylhydroperoxide.

Direct, regioselective and metal-free synthesis of fused N-heterocyclic iodides is reported. This regioselective C-H functionalization is mediated by tert-butylhydroperoxide (TBHP), via dual activation of molecular iodine and a heterocyclic substrate, resulting in the in situ generation of electrophilic iodine species (I(+)), and free radical(s) (t)BuO˙ or (t)BuOO˙, driving the iodination reaction.

DFT Study on Homolytic Dissociation Enthalpies of C—I Bonds

The C—I bond dissociation enthalpies (BDE) of various organic iodides were calculated using high-level theoretical methods including MP2 and CCSD(T) with extrapolated basis set as well as a number of density functional theory methods. After systematic evaluation of the theoretical results against available experimental C—I BDEs, it was found that the MPW-LYP1M method gave the lowest root mean square error. We, therefore, used this method to examine the substituent effects on different categories of C(sp3)—I and C(sp2)—I bonds. Furthermore, the remote substituent effects on the C—I BDEs of substituted iodobenzenes and substituted (iodomethyl)benzenes were also investigated at the same level. The C—I BDEs of typical heteroaromatic iodides including five-membered and six-membered heterocyclic iodides were also examined.

The Selective Deiodination of Iodoheterocycles Using the PhSiH3 – In(OAc)3 System

Nitrogen-containing π-deficient heterocyclic iodides such as iodoquinolines or iodopyridines were deiodinated by treatment with phenylsilane catalyzed by indium acetate to give the corresponding deiodinated heterocycles at ambient temperature.

A New, One-Step, Effective Protocol for the Iodination of Aromatic and Heterocyclic Compounds via Aprotic Diazotization of Amines

We have developed a convenient one-step preparation of aromatic and some heterocyclic iodides by the sequential diazotization-iodination of the aromatic amines with a KI/NaNO2/p-TsOH system in acetonitrile at room temperature. This method has general character and allows aryl iodides with either donor or acceptor substituents in various positions to be obtained from the corresponding amines in 50-90% yield.

Preparation of Highly Functionalized Heterocyclic Zinc Organometallics via a Li(acac)‐Catalysis of the I/Zn‐Exchange Reaction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Optically Active (2-Arylvinyl)glycine Derivatives by Palladium-Catalyzed Arylation of (S)-N-(Benzyloxycarbonyl)vinylglycine.

Phenyl, tolyl, anisyl, and 1-naphthyl iodides (7a-g, n) smoothly reacted with (S)-N-(benzyloxycarbonyl)-vinylglycine (6) in H2O in the presence of Pd(OAc)2, Bu4NCl, and NaHCO3 at 45°C, producing [S-(E)]-(2-arylvinyl)glycine derivatives 8a-g, n of high enantiomeric purity. The yields of the reactions of 3- (7f), 2- (7e), and 4-iodoanisoles (7g) increased in this order. This relationship between the yield and the position of substitution has been found to hold for bromophenyl iodides (7i-k), although somewhat lower chemical and optical yields were realized in these cases. Phenyl iodide 7l carrying an electron-withdrawing 4-acetyl group gave an unsatisfactory result, and more electron-deficient 4-nitrophenyl iodide (7m) did not provide the desired product. All these results suggest that the reaction is advantageous with electron-sufficient substrates 7. However, this was not the case for 4-iodophenol (7h), as well as some heterocyclic iodides.

Mass spectrometry of heterocyclic compounds. I—the behaviour of some quaternary heterocyclic iodides under electron impact

AbstractThe mass spectra of five quaternary heterocyclic iodides have been investigated. The main thermal process is the anhydro base formation by HI elimination. The influence of the second heteroatom, X, on the fragmentation mode of the thermally produced anhydro bases is analysed.