- Sequential C-S and S-N Coupling Approach to Sulfonamides
-
A one-pot three-component reaction involving nitroarenes, (hetero)arylboronic acids, and potassium pyrosulfite leading to sulfonamides was described. A broad range of sulfonamides bearing different reactive functional groups were obtained in good to excellent yields through sequential C-S and S-N coupling that does not require metal catalysts.
- Chen, Kai,Chen, Wei,Han, Bing,Chen, Wanzhi,Liu, Miaochang,Wu, Huayue
-
supporting information
p. 1841 - 1845
(2020/03/04)
-
- ZnO and ZnO-nanoparticles: Efficient and reusable heterogeneous catalysts for one-pot synthesis of N-acylsulfonamides and sulfonate esters
-
Commercially available and preparative ZnO nanoparticles are reported as efficient and reusable catalysts for the chemoselective synthesis of N-acylsulfonamides and sulfonate esters. A one-pot sequential sulfonylation and acylation of amines took place to afford the N-acylsulfonamides in excellent yields under solvent-free conditions. The ZnO catalyst can be reused for without significant loss of catalytic activity.
- Tamaddon, Fatemeh,Sabeti, Mohammad Reza,Jafari, Abbas Ali,Tirgir, Farhang,Keshavarz, Elham
-
experimental part
p. 41 - 45
(2012/01/12)
-
- 5-ALA ester formulations and use thereof
-
The present invention is directed to particles comprising 5-ALA esters salts, formulation thereof, related methods of preparation and methods of use thereof. In particular, the invention relates to particles comprising 5-ALA esters salts, formulation thereof useful in the treatment of a cancer and/or the diagnosis of a cancer cell such as in photodynamic therapy or photodynamic diagnosis.
- -
-
-
- Process for preparation of oxyglutaric acid ester derivatives
-
A process for preparing an oxyglutaric acid ester derivative of the formula: STR1 in which each of R1 and R2 is C1-5 alkoxy, C1-7 aralkyloxy, C7-9 halogenated aralkyloxy or phenyl, R4 is a hydroxyl-protecting group, and R5 is C1-10 alkyl which may have a substituent, comprises the steps of reacting a methyl phosphonate derivative or methyl phosphine oxide derivative with an oxyglutaric acid mono-ester to give a reaction product which comprises an oxyglutaric acid derivative having a phosphorus-containing group and a pentenedioic acid mono-ester (by-product), removing the pendenedioic acid mono-ester from the reaction product to isolate the oxyglutaric acid derivative, and converting the isolated oxyglutaric acid derivative into the oxyglutaric acid ester derivative. A process for obtaining an optically active oxyglutaric acid ester derivative is also disclosed.
- -
-
-
- Intermediacy of o-sulfonylium arenide ylides in the reactions of arenesulfonyl derivatives with strong bases: Insight into the puzzling rearrangement of N-arylarenesulfonamides into 2-aminodiaryl sulfones
-
Benzenesulfonyl derivatives, PhSO2E, such as benzenesulfonyl fluoride, phenyl benzenesulfonate, and N-methyl-N-phenylbenzenesulfonamide, have been found to undergo ortho-lithiation with lithium 2,2,6,6-tetramethylpiperidide (LTMP) in THF at -78 °C. The resulting lithio derivatives undergo 1,3-elimination of LiE to form the transient o-sulfonylium benzenide. The latter ylide, which may be stabilized by its carbenoid character and its complexation with LiE, can be trapped by benzophenone acting as a 1,3-dipolarophile to form the adduct, 3,3-diphenyl-1,2-benzoxathiole 1,1-dioxide. The alternative formation of the latter cyclic sulfonate by reaction of the initially formed o-lithio derivative with benzophenone and by subsequent cyclization was shown not to occur. If not trapped with benzophenone, such an ylide decomposes partly into SO2 and benzyne and then undergoes self-condensation to yield poly(phenylene-o,o′-biphenylene sulfones). o-Sulfonylium benzenide also can be captured by lithium alkoxides, either present adventitously or intentionally added, to generate the corresponding alkyl benzenesulfonate. However, such alkoxides, unaided by LTMP, are themselves unable to extract an ortho-proton from benzenesulfonyl fluoride or from N-methyl-N-phenylbenzenesulfonamide to yield the corresponding o-lithio derivative. With benzenesulfonyl fluoride the lithium alkoxide can also form the sulfonate ester by direct substitution at the sulfonyl group. The Closson-Hellwinkel rearrangement of N-methyl-N-phenylbenzenesulfonamide into o-(methylamino)diphenyl sulfone by RLi or LTMP is reinterpreted as proceeding by way of the 2-lithio- or 2,6-dilithiobenzenesulfonyl derivative which eliminates lithium N-methylanilide to form the o-sulfonylium benzenide or its 6-lithio derivative. Attack of the latter ylide, acting as an electrophile, upon the ortho-position of the presumably complexed LiNMePh then consummates the rearrangement.
- Eisch, John J.,Qian, Yun,Chiu, Chingchen S.
-
p. 1392 - 1398
(2007/10/03)
-
