13295-04-0Relevant articles and documents
SOME ORGANIC REACTIONS PROMOTED BY SAMARIUM DIIODIDE
Souppe, J.,Danon, L.,Namy, J.L.,Kagan, H.B.
, p. 227 - 236 (1983)
Various homoallylic alcohols and homobenzylic alcohols were prepared by the reaction between aldehydes and allylic or benzylic halides in the presence of samarium diiodide.This iodide is also a very good reagent for formation of pinacols from aldehydes or ketones.The reactions are especially fast and selective in the case of substituted benzaldehydes.The reactivities of various nitrogen functional groups (imine, oxime, nitro, azo, cyano) towards SmI2 were also examined.
Investigation of dissociative electron transfer mechanisms and reactivity patterns through kinetic amplification by a chain process
Costentin, Cyrille,Hapiot, Philippe,Medebielle, Maurice,Saveant, Jean-Michel
, p. 5623 - 5635 (2000)
The kinetic amplification offered by the S(RN)1 chain process allows the investigation of initiation electron-transfer/bond-breaking steps under very unfavorable thermodynamic conditions, which escape standard kinetic methods. Combining these observations with those derived under conventional thermodynamic conditions allows a considerable extension of the driving force window and thus opens the possibility of uncovering new mechanistic and reactivity patterns. The 'thermal' S(RN)1 reaction of 4-nitrobenzyl chloride with 2-nitropropanate ions is an illustrating example where two-problems of current interest could be investigated. One of these concerns the actively investigated and debated question of the dichotomy and connections between S(N)2 reactions and single electron transfer, particularly the question of catalysis of dissociative electron transfer that may result from mechanism bifurcation along an S(N)2 pathway. The other deals with the existence and magnitude of attractive interactions between fragments within the solvent and the influence of these interactions on the dynamics of dissociative electron transfer. Testing systematically the various mechanistic possibilities through simulation of product distribution and half-reaction time led to the conclusion that a small but sizable interaction between fragments within the solvent cage does exist and influences the dynamics of the dissociative electron-transfer reaction quite significantly. While similar effects have been uncovered or suspected in the electrochemical reductions of CCl4, of other benzyl halides and of phenacyl halides, the reduction of 4-nitrobenzyl chloride by the 2-nitropropanate ion provides a first example of the influence of an interaction between caged fragments on the dynamics of an homogeneous dissociative electron-transfer reaction. The simulations required a precise determination of the various rate constants involved in the chain process. Most of them were derived from cyclic voltammetry and redox catalysis. Particular care was exerted to estimate the ranges of uncertainty on these determinations and hence evaluate the reliability of the mechanistic conclusions.
Biginelli reaction of vicinal diols: A new route for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives
Jagadishbabu, Narasashetty,Shivashankar, Kalegowda
, p. 330 - 336 (2017/07/26)
Background: 3,4-Dihydropyrimidin-2(1H)-one derivatives are an important class of nitrogen heterocycles. These compounds present a wide range of biological activities viz antibacterial, antifungal, and antidiabetic. Although many synthetic methods are available in the literature for the synthesis of these molecules, many of these methods have their own limitations such as use of excess of expensive catalyst and poor yields. Methods: The synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives is developed through the reaction of 1,2-diols, ethyl acetoacetate and urea in the presence of lead tetraacetate in dry ethanol under reflux conditions. Results: A series of 3,4-dihydropyrimidin-2(1H)-one derivatives were synthesized in good yields (82-95%) under reflux for 2-3.5 hours in ethanol solvent. The structural assignments of these compounds were made on the basis of elemental analysis and spectroscopic data. Conclusion: This protocol is an alternative to existing procedure for the synthesis of Biginelli compounds. The present methodology reduces the number of steps in total synthesis.
Magnesium-induced pinacol coupling of aromatic aldehydes and ketones in water under ultrasound
Li, Ji-Tai,Bian, Yan-Jiang,Liu, Shu-Ming,Li, Tong-Shuang
, p. 196 - 198 (2007/10/03)
The pinacol coupling of aromatic aldehydes and ketones has been carried out in 20-62% and 10-91% yields, respectively with Mg and Mg-MgCl2 in water under ultrasound irradiation at room temperature for 3-4hr.
Pinacol coupling of aromatic aldehydes and ketones using magnesium in aqueous ammonium chloride under ultrasound
Li, Ji-Tai,Bian, Yan-Jiang,Zang, Hong-Jun,Li, Tong-Shuang
, p. 547 - 551 (2007/10/03)
The pinacol coupling reaction of aromatic aldehydes and ketones was performed in 8-95% yield with magnesium in 0.1 M aqueous NH4C1 under ultrasound irradiation at r.t. for 3 h.
EFFICIENT FORMATION OF PINACOLS FROM ALDEHYDES OR KETONES MEDIATED BY SAMARIUM DIIODIDE
Namy, J. L.,Souppe, J.,Kagan, H. B.
, p. 765 - 766 (2007/10/02)
Samarium diiodide is an excellent reagent for aldehyde or ketone coupling.With aromatic aldehydes, reactions are very fast with a complete selectivity versus substituents such as cyano, carbonyl or nitro groups.
