15774-73-9Relevant academic research and scientific papers
Catalyst-Controlled Stereoselective Barton–Kellogg Olefination
Schmidt, Tanno A.,Sparr, Christof
supporting information, p. 23911 - 23916 (2021/10/08)
Overcrowded alkenes are expeditiously prepared by the versatile Barton–Kellogg olefination and have remarkable applications as functional molecules owing to their unique stereochemical features. The induced stereodynamics thereby enable the controlled motion of molecular switches and motors, while the high configurational stability prevents undesired isomeric scrambling. Bistricyclic aromatic enes are prototypical overcrowded alkenes with outstanding stereochemical properties, but their stereocontrolled preparation was thus far only feasible in stereospecific reactions and with chiral auxiliaries. Herein we report that direct catalyst control is achieved by a stereoselective Barton–Kellogg olefination with enantio- and diastereocontrol for various bistricyclic aromatic enes. Using Rh2(S-PTAD)4 as catalyst, several diazo compounds were selectively coupled with a thioketone to give one of the four anti-folded overcrowded alkene stereoisomers upon reduction. Complete stereodivergence was reached by catalyst control in combination with distinct thiirane reductions to provide all four stereoisomers with e.r. values of up to 99:1. We envision that this strategy will enable the synthesis of topologically unique overcrowded alkenes for functional materials, catalysis, energy- and electron transfer, and bioactive compounds.
Carboxyl radical-assisted 1,5-aryl migration through Smiles rearrangement
Hossian, Asik,Jana, Ranjan
supporting information, p. 9768 - 9779 (2016/10/31)
We report herein, a silver(i)-catalyzed Smiles rearrangement of 2-aryloxy- or 2-(arylthio)benzoic acids to provide aryl-2-hydroxybenzoate or aryl-2-mercaptobenzoate dimer, respectively, through 1,5-aryl migration from oxygen or sulfur to carboxylate oxygen. Mechanistically, the aryl ether moiety undergoes an intramolecular ipso attack by the carboxyl radical followed by a C-O or C-S bond cleavage. Aryl-2-mercaptobenzoates undergo oxidative dimerization through a thiol moiety in situ.
ARYL SULFONAMIDE DERIVATIVES AND METHODS OF THEIR USE
-
Page/Page column 65, (2008/12/05)
Compounds of formula (I) and pharmaceutically acceptable salt thereof, which are modulators of secreted frizzled related protein-1, are disclosed. The compounds, and compositions containing the compounds, can be used to treat various diseases and disorders, including osteoporosis, arthritis, chronic obstructive pulmonary disease, cartilage defects, bone fractures, leiomyoma, acute myeloid leukemia, wound healing, prostate cancer, autoimmune inflammatory disorders, such as Graves ophthalmopathy, and combinations thereof.
Reactions of carbene intermediates from the reaction of trialkyl phosphites with dialkyl benzoylphosphonates: Intramolecular cyclisations of 2-substituted dialkyl benzoylphosphonates
Griffiths, D. Vaughan,Griffiths, Penelope A.,Karim, Khalku,Whitehead, Belinda J.
, p. 555 - 561 (2007/10/03)
The reaction of dialkyl benzoylphosphonates 1 with trialkyl phosphites leads to the formation of carbene intermediates 3 via the anionic intermediates 2. The carbene intermediates 3 (R = 2-PhO, 2-PhOCH2, and 2-PhS) have been generated by heating the corresponding 2-substituted dialkyl benzoylphosphonates with trimethyl phosphite and their subsequent reactions investigated. Reactions proceed either by intermolecular trapping of the carbene intermediates by trimethyl phosphite to give novel ylidic phosphonates 4, or by intramolecular routes involving carbene insertion into the π-system of the phenyl ring in the substituent. Studies using methyl-substituted derivatives have shown that the formation of the thioxanthenylphosphonate 15 (X = S, R′ = R″ = Me) proceeds via a spiro diene intermediate 14 (X = S, R′ = R″ = Me).
Synthesis and antitumor activity of some new 2-chloroethylnitrosoureas
Filippatos,Papadaki-Valiraki,Roussakis,Verbist
, p. 451 - 456 (2007/10/02)
The synthesis of a series of N-(2-chloroethyl)-N'-(9H-xanthen-9-yl)-N-nitrosoureas and N-(2-chloroethyl)-N'-(9H-thioxanthen-9-yl)-N-nitrosoureas is described. The title compounds were evaluated against NSCLCN6 L16 bronchial epidermoid carcinoma in vitro and some of them were found to be active. N-(2-chloroethyl)-N'-(2-methoxy-9H-xanthen-9-yl)-N-nitrosourea (8e) was active against leukemia P388 tumor system in mice.
Dibenzocyclooctene-, Dibenzochalcocine-, and Diarenochalconinediones
Hellwinkel, Dieter,Bohnet, Siegbert
, p. 1151 - 1174 (2007/10/02)
2,2'-Oxybis-, -thiobis-, and -methylenebisbenzoic esters 2a-c react with methyllithium in ether to give low yields of 5H-dibenzochalcocine-5,7(6H)-diones 6a, 7a, and dibenzocyclooctene-5,7(6H,12H)-dione (8), respectively.Very good yields of such heterocycles with oxygen (6a-h, 37), sulfur (7a-h, 38) and selenium (36) as key atom are obtained when diaryl ethers (21, 22, 25), -sulfides (27, 29, 30), and -selenides (33) that contain 2'-acetyl- (or -propionyl-) and 2-methoxycarbonyl groups are treated with sodium hydride in boiling toluene.Analogously are prepared the dibenzoxonine-11,13(6H,12H)diones 62a-c and 7H-benzonaphthothionine-7,9-(8H)-dione (65) which are expanded by one ring member.In the analogous reaction of a corresponding benzophenone derivative 35, spiro-3(2H),3'-dione (41) is formed in a tandem reaction. - Under phase transfer conditions the dibenzochalcocinediones 6, 7, 36 and also the corresponding nitrogen cycles 5 react to give mixtures of C- (42-45) and O-alkyl derivatives (46-49).Methyllithium and diisobutylaluminium hydride provide the carbinols 50-54.With bromine and SO2Cl2, respectively, the methylene group is mono- or dihalogenated to the products 56, 57; defined nitration was only possible for the oxacycle 6a.
Methyl substituted thioxanthones and thioxanthone-10,10-dioxides
Brindle, Ian D.,Doyle, Paul P.
, p. 1869 - 1871 (2007/10/02)
The preparation of all four monomethylthioxanthones and their corresponding dioxides is described.A previously published synthesis of the 2- and 3-methylthioxanthones by Gilman and Diehl has been shown to produce the 2- and 4-methyl isomers.
Studies in Rearrangement of 2-(Arylthio)benzohydroxamic Acids to the Corresponding 2-(Arylsulphinyl)benzamides
Dhareshwar, G. P.,Chhaya, P. N.,Hosangadi, B. D.
, p. 831 - 835 (2007/10/02)
2-(2'-Methoxyphenylthio)-(III)-, 2-(4'-methoxyphenylthio)-(IV)-, 2-(2'-methylphenylthio)-(V)- and 2-(4'-methylphenylthio)-(VI)-benzohydroxamic acids on treatment with polyphosphoric acid yield 2-(2'-methoxyphenylsulphinyl)-(VII)-, 2-(4'-methoxyphenylsulphinyl)-(VIII)-, 2-(2'-methylphenylsulphinyl)-(IX)- and 2-(4'-methylphenylsulphinyl)-(X)-benzamides respectively, illustrating the generality of rearrangement reported earlier .The rearrangement can also be effected with other reagents like xylene-P2O5, perchloric acid- gl. acetic acid and trifluoracetic acid. 2-Methylthiobenzohydroxamic acid (XI) and 4-(phenylthio)benzohydroxamic acid (XII) when treated with PPA yield benzothiazolone (XIII) and 4-aminodiphenyl sulphide (XIV).Experimental evidence has been presented which points to a concerted mechanism for the intramolecular oxygen transfer.
