First Example Of Reaction Research Articles

Reaction between Azidyl Radicals and Alkynes: A Straightforward Approach to NH-1,2,3-Triazoles.

Reaction between nitrogen-centered radicals and unsaturated C-C bonds is an effective synthetic strategy for the construction of nitrogen-containing molecules. Although the reactions between nitrogen-centered radicals and alkenes have been studied extensively, their counterpart reactions with alkynes are extremely rare. Herein, the first example of reactions between azidyl radicals and alkynes is described. This reaction initiated an efficient cascade reaction involving inter-/intramolecular radical homolytic addition toward a C-C triple bond and a hydrogen-atom transfer step to offer a straightforward approach to NH-1,2,3-triazoles under mild reaction conditions. Both the internal and terminal alkynes work well for this transformation and some heterocyclic substituents on alkynes are compatible. This mechanistically distinct strategy overcomes the inherent limitations associated with azide anion chemistry and represents a rare example of reactions between a nitrogen-centered radicals and alkynes.

ChemInform Abstract: First Example of Reaction of Asymmetric Dienone Derivatives of Cyclohexane with 3‐Amino‐1,2,4‐triazole. Formation of Isomeric Octahydrotriazoloquinazolines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

First example of reaction of asymmetric dienone derivatives of cyclohexane with 3-amino- 1,2,4-triazole. Formation of isomeric octahydrotriazoloquinazolines

First example of reaction of asymmetric dienone derivatives of cyclohexane with 3-amino- 1,2,4-triazole. Formation of isomeric octahydrotriazoloquinazolines

On the reactivity of some 2-methyleneindolines with β-nitroenamines, α-nitroalkenes, and 1,2-diaza-1,3-butadienes

A study of the behaviour of some electron-rich 2-methyleneindolines ( 1 – 3 ) with different electron-poor reagents (formation of new carbon–carbon and nitrogen–carbon bonds) has furnished interesting results from both synthetic and the mechanistic viewpoints. Enamines 1 – 3 have been reacted with the β-nitroenamines 4 – 7 (reaction CeCl 3 ·7H 2 O promoted), giving the polymethine dyes 14 – 23 . The same bases 1 – 3 have been nitroalkylated with the nitroolefins 8 – 10 , furnishing the indolines 24 – 32 , and the diastereoselectivity of the reaction has been thoroughly investigated. The most unexpected results derived from the first example of reaction of Fischer's bases with 1,2-diaza-1,3-butadienes. In fact, with 11 – 13 , the ‘unknown’ indoline spirodihydropyrroles 33 – 40 were formed. Their structures were unambiguously assigned, and we determined, as an example, that of 33 by X-ray analysis.

ChemInform Abstract: Ceric Ammonium Nitrate (CAN) Mediated Novel Dimerizations of 4‐Hydroxyquinolin‐2(1H)‐ones: The First Example of Reactions of Oxygen‐Centered Radicals from 1,3‐Dicarbonyl Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Ceric ammonium nitrate (CAN) mediated novel dimerizations of 4-hydroxyquinolin-3(1 H)-ones: the first example of reactions of oxygencentered radicals from 1,3-dicarbonyl compounds

Reactions of 4-hydroxyquinolin-2(1 H)-ones ( 1) and 3-alkylated 4-hydroxyquinolin-2(1 H)-ones ( 2) with CAN in methanol gave quinolin-2(1 H)-one dimers 3, 10 and 11 with CC and CO linkages between the two nitrogent containing six-member rings, respectively, showing the ambident reactivities of α,α′-dicarbonylalkyl radicals as carbon- and oxygen-centered radicals.

Fluoride Ion Promoted Azomethine Ylid Generation from 1-Methyl-2-[methylthio(trimethylsilylmethylimino)methylimino]-1,2-dihydropyridine, a Synthetic Equivalent of Aminonitrile Ylid

1-Methyl-2-[methylthio(trimethylsilylmethylimino) methylimino]-1,2-di- hydropyridine (1), prepared from 2-amino-1-methylpyridinium iodide in 3 steps, reacted with carbonyl compounds in the presence of cesium fluo- ride in acetonitrile to give 2-(1-methyl-1,2-dihydropyridylidene)amino- oxazoline derivatives (6) via the 1,3-dipolar cycloadditon. This reac- tion was the first example of reaction of aminonitrile ylid with the C = O double bond

Organische Synthesen mit Übergangsmetallkomplexen, 41. Thioenolether durch Insertion von Alkinen in MC‐Bindungen von Thiocarben‐Komplexen und Liganden‐Abspaltung an Kieselgel

Organic Syntheses via Transition Metal Complexes, 41 1. ‐ Thioenol Ethers by Insertion of Alkynes into M = C Bonds of Thiocarbene Complexes and Disengagement of Ligands on Silica GelA first example of reactions between alkynes and thiocarbene complexes is described. Et2NCCCCH3 (2) adds to (alkylthio)phenylcarbene complexes LnMC(SR)C6H5 (1) [LnM = Cr(CO)5. W(WO)5; RCH2CHCH2, CH2C6H5, c‐C6H11, t‐C4H9, C6H5] with insertion of the CC into the MC bond to form stereoselectively [(E)‐β‐(alkylthio)alkenyl]aminocarbene complexes LnMC(NEt2) ‐ C(CH3)C(SR)C6H5 [(E)‐3a–g]. With tungsten, but not with chromium, small amounts of indanone derivatives 4–6 were also obtained. We describe a straightforward and efficient method for the disengagement of ligands from carbene chromium complexes 3 on silica gel. Metal residues remain attached to the solid phase, and products are isolated by elution. Depending on the reaction conditions, different thioenol ethers 7–9 were obtained. Thus (E)‐3a–d on silica gel at ambient temperature under the influence of air give β‐(alkylthio)propenamides OC(NEt2)‐C(CH3)C(SR)C6H5 [(E)‐] and β‐(alkylthio)propenals OCH–C(CH3) = C(SR)C6H5 [(E)‐8]. Thermolysis of 3 on silica gel in the absence of oxygen leads to the formation of aldehydes 8 and 3‐(alkylthio)‐1‐indanones 5. Thermolysis of 3 on silca gel in the presence of sulfur yields β‐(alkylthio)propenethioamides 9 as the only products.