23304-24-7Relevant academic research and scientific papers
A facile one pot synthesis of substituted pyrazole derivatives
Haouas, Amel,Hamadi, Naoufel Ben,Nsira, Asma,Msadek, Moncef
, p. 435 - 437 (2013/09/12)
Diazo compounds derived from aromatic aldehydes were reacted with derivatives of (Z)-2-arylidene-2H-benzofuran- 3-ones to give new highly substituted heterocyclic pyrazoles. The structures of the synthesised compounds were determined on the basis of their
Straightforward reductive esterification of carbonyl compounds with carboxylic acids through tosylhydrazone intermediates
Garcia-Munoz, Angel-Humberto,Tomas-Gamasa, Maria,Perez-Aguilar, M. Carmen,Cuevas-Yanez, Erick,Valdes, Carlos
supporting information; experimental part, p. 3925 - 3928 (2012/08/28)
The reaction of carboxylic acids with tosylhydrazones in basic media gives rise to the corresponding esters through an O-H insertion reaction in the in situ generated diazo compound. The process is operationally very simple, catalyst free, and very general with regard to the structure of both coupling partners. In particular, the esterification can be accomplished by employing tosylhydrazones derived from enolizable carbonyl compounds. Considering the ready availability of tosylhydrazones from carbonyl compounds, this reaction can be visualized as a reductive esterification of carbonyl compounds.
An enantioselective synthesis of 2-aryl cycloalkanones by sc-catalyzed carbon insertion
Rendina, Victor L.,Moebius, David C.,Kingsbury, Jason S.
supporting information; experimental part, p. 2004 - 2007 (2011/07/07)
Current methods for asymmetric α-arylation require blocking groups to prevent reaction at the R0-carbon, basic conditions that promote racemization, or multistep synthesis. This work records the first catalytic enantioselective examples of the diazoalkane-carbonyl homologation reaction. Medium ring 2-aryl ketones are prepared in one step in up to 98:2 er and 99% yield from the unsubstituted lower homologue by Sc-catalyzed aryldiazomethyl insertion with simple bis- and tris(oxazoline) ligands.
A ceric ammonium nitrate N-dearylation of N-p-anisylazoles applied to pyrazole, triazole, tetrazole, and pentazole rings: Release of parent azoles. Generation of unstable pentazole, HN5/N5-, in solution
Butler, Richard N.,Hanniffy, John M.,Stephens, John C.,Burke, Luke A.
, p. 1354 - 1364 (2008/04/12)
(Chemical Equation Presented) The reaction of cerium(IV) ammonium nitrate (CAN) with a range of N-(p-anisyl)azoles in acetonitrile or methanol solvents leads to N-dearylation releasing the parent NH-azole and p-benzoquinone in comparable yields. The scope and limitations of the reaction are explored. It was successful with 1-(p-anisyl)pyrazoles, 2-(p-anisyl)-1,2,3-triazoles, 2-(p-anisyl)-2H-tetrazoles, and 1-(p-anisyl)pentazole. The dearylation renders the p-anisyl group as a potentially useful N-protecting group in azole chemistry. The azole released in solution from 1-(p-anisyl)pentazole is unstable HN5, the long-sought parent pentazolic acid. p-Anisylpentazole samples were synthesized with combinations of one, two, and three 15N atoms at all positions of the pentazole ring. The unstable HN 5/N5- produced at -40°C did not build up in the solution but degraded to azide ion and nitrogen gas with a short lifetime. The 15N-labeling of the N3- ion obtained from all samples proved unequivocally that it came from the degradation of HN 5 (tautomeric forms) and/or its anion N5- in the solution.
THE PHENYLCARBENE REARRANGEMENT REVISITED
Gaspar, Peter P.,Hsu, Jong-Pyng,Chari, Sarangan,Jones, Maitland Jr.
, p. 1479 - 1508 (2007/10/02)
The evolution of mechanistic ideas about the phenylcarbene rearrangement has been reviewed, and three closely linked problems have been identified toward whose solution this research has been aimed: 1.Why do the ratios of the stable end products from the rearrangements of o-, m- and p-tolylmethylene differ when all three reactions have been thought to pass through a common intermediate? 2.Why does the rearrangement of 2-methylcycloheptatrienylidene lead to exclusive formation of styrene? 3.What is the mechanism of styrene formation from o-tolylmethylene? New mechanisms have been proposed in which m- and p-tolylmethylene can rearrange to styrene without necessarily being converted to o-tolylmethylene.The formation of a small amount of 2,6-dimethylstyrene from the rearrangement of 3,4,5-trimethylphenylmethylene is viewed as evidence for such a mechanism, and a set of interconverting norcaradienylidenes are believed to be the crucial intermediates.Other alternatives are considered and rejected on the basis of the rearrangement products of 3,5-dimethyl- and 3,4,5-trimethylphenylmethylene.
Diazoalkane Complexes of Molybdenum and Tungsten
Hillhouse, Gregory L.,Haymore, Barry L.
, p. 1537 - 1548 (2007/10/02)
Ordinary diazoalkanes, N2CHR' and N2C(CH3)R' (R' = C6H5, p-CH3C6H4), were found to react with M(CO)3(S2CNR2)2 (M = Mo, W; R = CH3, C2H5; R2 = (CH2)4) at room temperature to form stable complexes of the type M(CO)(N2CHR')(S2CNR2)2 which were conveniently isolated in good yields.Oxidaion of M(CO)(N2CHR')(S2CNR2)2 with 1 equiv of Cl2 or Br2 produced MX2(N2CHR')(S2CNR2)2 (X = Cl, Br) which were isolated as chloroform solvates.The addition of excess HBr to W(CO)(N2CHR')(S2CNMe2)2 gave a red solid which analyzed for WBr2(N2H2CHR')(S2CNMe2)2.Physical and spectroscopic data suggest that the diazoalkane ligands in the above complexes behave as terminal, singly bent, four-electron donor ligands.The NMR chemical shifts of the methine proton in N2CHR' ligands indicate that the M(S2CNR2)2 unit is strogly electron withdrawing.Syntheses for new tungsten compounds, W(CO)3(S2CNR2)2, W(CO)2(S2CNR2)2, W(CO)2(L)(S2CNR2)2 (L = p-CH3C6H4NHNH2, 4-CH3C5H4N), WBr2(S2CNR2)2, W(S2CNR2)4, and WBr3(S2CNR2)2, are also reported.
Regioselectivity in the Addition of Singlet and Triplet Carbenes to 1,1-Dimethylallene. A Probe for Carbene Multiplicity
Creary, Xavier
, p. 1611 - 1618 (2007/10/02)
Singlet carbenes add preferentially to the more substituted bond of 1,1-dimethylallene (1), to give methylenecyclopropanes 3 as the major product.In contrast, many triplet carbenes add with differing regioselectivity, giving the thermodynamically preferre
