21613-44-5Relevant academic research and scientific papers
Amine-free approach toward N-toluenesulfonyl amidine construction: A phosphite-mediated beckmann-like coupling of oximes and p-toluenesulfonyl azide
Fleury, Lauren M.,Wilson, Erin E.,Vogt, Monika,Fan, Tiffany J.,Oliver, Allen G.,Ashfeld, Brandon L.
, p. 11589 - 11593 (2013)
Atom hopping: A chlorophosphite-mediated Beckmann ligation of oximes and p-toluenesulfonyl azide gives access to N-sulfonyl phosphoramidines in good to excellent yields. The reaction proceeds under exceptionally mild conditions and constitutes a bioorthogonal approach toward amidines by avoiding the use of amines and transition-metal catalysts. dmp-ol=3,3-dimethylpropanediol. Copyright
Dehydrative Beckmann rearrangement and the following cascade reactions
Liu, Yinghui,Wei, Yongjiao,Xie, Lan-Gui
supporting information, (2021/11/16)
The Beckmann rearrangement has been predominantly studied for the synthesis of amide and lactam. By strategically using the in situ generated Appel's salt or Mitsunobu's zwitterionic adduct as the dehydrating agent, a series of Beckmann rearrangement and following cascade reactions have been developed herein. The protocol allows the conversion of various ketoximes into amide, thioamide, tetrazole and imide products in modular procedures. The generality and tolerance of functionalities of this method have been demonstrated.
o-Phthalic Anhydride/Zn(OTf)2 co-catalyzed Beckmann rearrangement under mild conditions
Xu, Ze-Feng,Zhang, Teng,Hong, Wenjun
supporting information, p. 3113 - 3117 (2019/05/08)
o-Phthalic anhydride/Zn(OTf)2 co-catalyzed Beckmann rearrangement was developed, producing the corresponding amide in up to 99% yield with acid-sensitive functionalities tolerated well, and the scale of the reaction could be enlarged to 77 mmol and the excellent yield was maintained. A successive procedure was developed. Moreover, the reaction was carried out at rt under nearly neutral conditions, and the workup was concise. These features illustrated the potential of the protocol in amide synthesis.
Stereospecific synthesis of 1,5-disubstituted tetrazoles from ketoximes via a Beckmann rearrangement facilitated by diphenyl phosphorazidate
Ishihara, Kotaro,Shioiri, Takayuki,Matsugi, Masato
supporting information, p. 1295 - 1298 (2019/04/13)
A novel method for the stereospecific synthesis of 1,5-disubstituted tetrazoles from ketoximes via the Beckmann rearrangement was developed using diphenyl phosphorazidate (DPPA) as both the oxime activator and azide source. Various ketoximes were transformed into the corresponding 1,5-disubstituted tetrazoles with exclusive trans-group migration and no E-Z isomerization of the ketoxime. This method enables the preparation of 1,5-disubstituted tetrazoles without using toxic or explosive azidation reagents.
Cu(ii)-Catalyzed asymmetric boron conjugate addition to α,β-unsaturated imines in water
Kitanosono, Taku,Xu, Pengyu,Isshiki, Satoshi,Zhu, Lei,Kobayashi, Shu
supporting information, p. 9336 - 9339 (2014/08/05)
Enantioselective conjugate addition of bis(pinacolato)diboron to α,β-unsaturated imines proceeds smoothly in water in the presence of a chiral copper(ii) complex consisting of Cu(OAc)2 and chiral 2,2′-bipyridine. The corresponding β-boryl imines, which were oxidized to β-hydroxy imines, further leading to γ-amino alcohols, were obtained in high yields and high enantioselectivities.
Rhodium(III)-catalyzed synthesis of pyridines from α,β- unsaturated ketoximes and internal alkynes
Too, Pei Chui,Noji, Toshiharu,Lim, Ying Jie,Li, Xingwei,Chiba, Shunsuke
supporting information; experimental part, p. 2789 - 2794 (2012/01/11)
A method for the synthesis of highly substituted pyri-dines from ,-unsaturated oximes and internal alkynes has been developed using [Cp*RhCl2]2-CsOPiv as the catalyst system. The present transformation is carried out by a redox-neutral sequence of vinylic C-H rhodation, alkyne insertion, and C-N bond formation of the putative vinyl rhodium intermediate with the oxime nitrogen, where the N-O bond of oxime derivatives could work as an internal oxidant to maintain the catalytic cycle. Georg Thieme Verlag Stuttgart · New York.
Friedel-Crafts-type reactions involving di- and tricationic species. Onium-allyl dications and O,O-diprotonated aci-nitro species bearing a protonated carbonyl group
Ohwada, Tomohiko,Yamagata, Naoko,Shudo, Koichi
, p. 1364 - 1373 (2007/10/02)
Stable carbocations do not react with nonactivated benzenes. For example, acetophenone does not react with benzene in the presence of trifluoromethanesulfonic acid (TFSA), while trifluoroacetophenone does do so under acidic conditions owing to activation of the electrophilicity of the hydroxycarbenium cation by the trifluoromethyl group. This and other studies suggest that an electron-withdrawing substituent on the cationic center increases the reactivity toward benzenes. In this paper, involvement of multiply positively charged (dicationic and tricationic) species, which have sufficient electrophilicity toward benzene, is demonstrated in the acid-catalyzed reactions of cinnamaldehyde and its derivatives and also in the acid-catalyzed reactions of nitromethanes. The species formed from cinnamaldehyde, cinnamaldimine, cinnamaldoxime, and their derivatives in TFSA or TFSA-SbF5 have an adequate reactivity toward benzene. O-Protonated cinnamaldehyde and its derivatives, N-protonated cinnamaldimine, and N,N-dimethylcinnamaldiminium salt do not react with benzene. Since a strong acid catalyst is required for the reactions, participation of doubly protonated species, onium-allyl dications, is proposed. Ab initio calculations of (1) the donor-acceptor interaction energies of a neutral donor (such as water and ammonia) and a doubly charged allyl dication and (2) proton affinities demonstrated that the ammonium-allyl dication is more stable than the oxonium-allyl dication, in accordance with the experimental observation. Nitronic acids also react with benzene at the ipso position with respect to the nitro group to give the phenylated oximes in the presence of TFSA. The reaction with benzene is not catalyzed by trifluoroacetic acid, which is sufficiently acidic to monoprotonate a nitronic acid to the protonated aci-nitro form. The reaction requires a stronger acid, trifluoromethanesulfonic acid, suggesting intervention of the dication formed by O,O-diprotonation of acinitroalkanes rather than the monoprotonated aci-nitroalkane. As a result of further study on the phenylation reactions, we found a facile phenylation reaction of nitromethanes substituted with an electron-withdrawing group, catalyzed by TFSA, to give phenylated α-carbonyloximes in high yields. A triply positively charged cation, an O,O-diprotonated aci-nitro species bearing a protonated ethoxycarbonyl group, which can react with nonactivated benzene, is proposed to be an intermediate in this reaction.
Synthesis and evaluation of some alkoxy-, chloro-, and acyloxy-conjugated styryl ketones against P-388 lymphocytic leukemia and an examination of the metabolism and toxicological effects of 1-(m-ethoxymethyloxyphenyl)-1-nonen-3-one in rats
Dimmock,Kirkpatrick,Webb,Cross
, p. 1000 - 1007 (2007/10/02)
A number of analogs of a new antineoplastic agent, 1-(m-ethoxymethyloxyphenyl)-1-nonen-3-one (IIIa) were prepared and evaluated against murine P-388 lymphocytic leukemia. Metabolic studies of IIIa in rats showed that it was sequestered rapidly to the brai
