2176-28-5Relevant academic research and scientific papers
Rhodium(I)-Catalyzed Aryl C-H Carboxylation of 2-Arylanilines with CO2
Gao, Yuzhen,Cai, Zhihua,Li, Shangda,Li, Gang
, p. 3663 - 3669 (2019/05/17)
An unprecedented Rh(I)-catalyzed, amino-group-assisted C-H carboxylation of 2-arylanilines with CO2 under redox-neutral conditions has been developed. This reaction was promoted by a phosphine ligand with t-BuOK as the base and did not require the use of additional strong organometallic reagent. It enabled an efficient direct conversion of a broad range of 2-(hetero)arylanilines including electron-deficient heteroarenes to various phenanthridinones. Possible intermediates of the reaction were also evaluated in the preliminary mechanistic studies.
Different behavior of nitrenes and carbenes on photolysis and thermolysis: Formation of azirine, ylidic cumulene, and cyclic ketenimine and the rearrangement of 6-phenanthridylcarbene to 9-phenanthrylnitrene
Kvaskoff, David,Bednarek, Pawel,George, Lisa,Pankajakshan, Sreekumar,Wentrup, Curt
, p. 7947 - 7955 (2007/10/03)
Flash vacuum thermolysis (FVT) of 9-azidophenanthrene 8, 6-(5-tetrazolyl)phenanthridine 18, and [1,2,3]triazolo[l,5-f]phenanthridine 19 yields 9-cyanofluorene 12 as the principal product and 4-cyanofluorene as a minor product. In all cases, when the product is condensed at or below 77 K, the seven-membered ring ketenimine 24 is detectable by IR spectroscopy (1932 cm-1) up to 200 K. Photolysis of Ar matrix isolated 8 at λ = 308 or 313 nm generates at first the azirine 26, rapidly followed by the ylidic cumulene 27. The latter reverts to azirine 26 at λ > 405 nm, and the azirine reverts to the ylidic cumulene at 313 nm. Nitrene 9 is observed by ESR spectroscopy following FVT of either azide 8, tetrazole 18, or triazole 19 with Ar matrix isolation of the products. Nitrene 9 and carbene 21 are observed by ESR spectroscopy in the Ar matrix photolyses of azide 8 and triazole 19, respectively.
Medium and Substituent Effects on the Photochemistry of Phenanthridine N-Oxides. Is an Intermediate of Diradical Character involved in the Photorearrangement of Heterocyclic N-Oxides?
Albini, Angelo,Fasani, Elisa,Frattini, Valeria
, p. 235 - 240 (2007/10/02)
The photochemistry of several 6-substituted phenanthridine N-oxides has been investigated, or reinvestigated, in benzene and ethanol.The main processes observed are: (a) 1,2-oxygen and substituent shift to yield N-substituted phenanthridones (2) and (b) ring enlargements to dibenzo-1,3-oxazepines (7).With 6-diphenylmethylphenanthridine N-oxide (1b) rearrangement (a) predominates and occurs with 45percent substituent loss in benzene (but only 2percent in ethanol).With the 6-phenylderivative (1c) process (a) predominates in ethanol and process (b) in benzene and with the 6-p-nitrophenyl derivative (1d) the latter process predominates in both solvents.With 6-cyanophenanthridine N-oxide (1e) rearrangement (b) predominates in benzene; in the presence of 2,3-dimethylbutene (but not of cyclohexene) addition products are obtained; with dienes deoxygenation is the main process.Medium and substituents may change the nature of the lowest excited singlet state, but more importantly affect the stability of an intermediate of diradical character occurring along the reaction pathway, thus driving it towards rearrangement (a) or (b).Intermediate diradicals are unambiguously indicated only in particular cases but their role is probably more general.
RADICALOID INTERMEDIATES IN THE PHOTOCHEMISTRY OF 6-CYANOPHENATHRIDINE N-OXIDE
Albini, Angelo,Pasani, Elisa,Buchardt, Ole
, p. 4849 - 4852 (2007/10/02)
Irradiation of 6-cyanophenanthridine N-oxide in presence of 2,3-dimethyl-2-butene resulted in a novel type of photoaddition with rearrangement to give 2-cyano-8,8,9,9-tetramethyl--dibenzo-1,3-oxazonin and 6-(2-cyano-1,1,2-trimethylpropyloxy)phenanthridine as a minor product, which is regarded as strong evidence for an initial photochemical generation of a biradical, and not an oxaziridine as previously suggested.
