5219-04-5Relevant articles and documents
Oxidative aromatic C-O bond formation: synthesis of 3-functionalized benzo[b]furans by FeCl3-mediated ring closure of a-Aryl ketones
Liang, Zhidan,Hou, Weizhe,Du, Yunfei,Zhang, Yongliang,Pan, Yan,Mao, Deng,Zhao, Kang
supporting information; experimental part, p. 4978 - 4981 (2010/01/16)
A variety of 3-functionalized benzo[b]furans were achieved by way of a FeCl3-medlated Intramolecular cyclization of electron-rich a-aryl ketones. The alkoxy substituent on the benzene ring In the substrates was essential for an efficient cyclization to occur. This novel method allows the construction of benzo[b]furan rings by joining the O-atom on the side chain to the benzene ring via direct oxidative aromatic C-O bond formation.
Dynamic kinetic resolution in the asymmetrie synthesis of β-amino acids by organocatalytic reduction of enamines with trichlorosilane
Malkov, Andrei V.,Stoncius, Sigitas,Vrankova, Kvetoslava,Arndt, Matthias,Kocovsky, Pavel
supporting information; experimental part, p. 8082 - 8085 (2009/09/29)
A new methodology based on the organocatalytic asymmetric hydrosilylation of enamines that allows a direct access to a range of β3 and β2.3-amino acid derivatives was presented. The results show a successful reduction of aromatic substrates, a sterically more hindered ortho-substituted derivatives, and the thiophenyl analogue exhibiting lower reactivity. Fast enamine-imine equilibration is crucial as imines are chiral but racemic, while α-alkyl β-amino acids can be accessed by the symmetrical Mannich reaction. The α-alkyl derivatives have relative and absolute configuration due to their reduction with LiAlH4 into a known amino alcohols. Predominant formation of the anti isomer in 3o is consistent with conformation of the imine intermediate in the catalytic reduction.
Pyrazolo[1,5-a]pyrimidines as estrogen receptor ligands: Defining the orientation of a novel heterocyclic core
Compton, Dennis R.,Carlson, Kathryn E.,Katzenellenbogen, John A.
, p. 5681 - 5684 (2007/10/03)
We investigated the pyrazolo[1,5-a]pyrimidine system as a novel heterocyclic scaffold for the development of estrogen receptor (ER) ligands. By altering the pattern of hydroxyl substitution, we established the orientation that is most favorable for ER bin
Expedient acylations of primary and secondary alkyl cyanides to α-substituted β-ketonitriles
Katritzky, Alan R.,Abdel-Fattah, Ashraf A. A.,Wang, Mingyi
, p. 4932 - 4934 (2007/10/03)
Primary and secondary cyanides are efficiently acylated with N-acylbenzotriazoles 3a-f (derived from a variety of acids) to afford the corresponding α-substituted β-ketonitriles 5a-r in 67-96% yields.
The reaction of 2-(tetrazol-5-yl)alkyl ketones and of 2-(tetrazol-5-yl)alkanoic acid derivatives with lead tetraacetate. A novel method of preparation of alk-2-ynyl ketones and alk-2-ynoic acid derivatives
Fetter,Nagy,Giang,Kajtar-Peredy,Rockenbauer,Korecz,Czira
, p. 1131 - 1139 (2007/10/03)
The majority of tetrazolylacetyl derivatives 2 and 7, when treated with lead tetraacetate in dry 1,4-dioxane at room or lower temperature, are oxidized with elimination of molecular nitrogen mainly to the corresponding alkynoyl derivatives 4 and 8, respectively. Vinylidenes (25) have been shown to be the intermediates of the reaction. The reaction does not take place when either the tetrazolyl group is N-substituted or the carbon atom separating the tetrazolyl and the carbonyl groups is disubstituted or these two groups are separated by two carbon atoms as in compound 17. The reaction offers a convenient method for the conversion of 2-cyanoacetyl derivatives into alk-2-ynoyl derivatives via intermediate tetrazolylacetyl derivatives. The 4-methoxyanilide 7o reacts differently, affording the fused heterocyclic compounds 19o and 20o.
Enolate Ions as ss-Activators of ortho-metalation: Direct Synthesis of 3-Aminoindenones
Kayaleh, Nadim E.,Gupta, Ramesh C.,Johnson, Francis
, p. 4515 - 4522 (2007/10/03)
ss-Ketonitriles derived from a Claisen condensation of benzoate esters with alkyl- or phenylacetonitriles lead to 3-aminoindenones in the presence of excess LDA. This new reaction is also applicable to pyridine carboxylic esters. All of the 3-aminoindenones and their aza analogues can be hydrolyzed by acid to give the corresponding 1,3-indandiones. The mechanism of the reaction falls into the directed-ortho-metalation class in which the initial enolate ion of the keto-nitrile directs self-metalation at an ortho position. The new anion then cyclizes onto the nitrile group to generate an aminoindenone. Surprisingly the simplest member of the series, benzoylacetonitrile, does not undergo cyclization. Mechanistic isotope studies revealed that this substance preferentially and directly forms a dianion on the side chain, which is not further deprotonated at the ortho position of the aromatic ring.
A new anionic cyclization reaction: Condensation of benzoate esters with nitriles to give 3-amino-2-inden-1-ones
Kayaleh, Nadim E.,Gupta, Ramesh C.,Morrissey, John F.,Johnson, Francis
, p. 8121 - 8124 (2007/10/03)
A new type of anionic cyclization has been discovered in which the condensation of alkyl benzoates with simple nitriles, induced by an excess of LDA, leads directly to substituted-3-amino-1-ones. The corresponding intermediate β-oxonitriles undergo cyclization to give, in most instances, superior yields of the same compounds. Acid hydrolysis of these indenones leads in high yield to the corresponding biologically active (anticoagulant) indandiones.
