- Organic photoredox catalytic α-C(sp3)-H phosphorylation of saturated: Aza -heterocycles
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A metal-free C(sp3)-H phosphorylation of saturated aza-heterocycles via the merger of organic photoredox and Br?nsted acid catalyses was established under mild conditions. This protocol provided straightforward and economic access to a variety of valuable α-phosphoryl cyclic amines by using commercially available diarylphosphine oxide reagents. In addition, the D-A fluorescent molecule DCQ was used for the first time as a photocatalyst and exhibited an excellent photoredox catalytic efficiency in this transformation. A series of mechanistic experiments and DFT calculations demonstrated that this transformation underwent a sequential visible light photoredox catalytic oxidation/nucleophilic addition process.
- Yi, Ming-Jun,Xiao, Teng-Fei,Li, Wen-Hui,Zhang, Yi-Fan,Yan, Pen-Ji,Zhang, Baoxin,Xu, Peng-Fei,Xu, Guo-Qiang
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supporting information
p. 13158 - 13161
(2021/12/16)
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- Heterogeneous Catalytic Reduction of Tertiary Amides with Hydrosilanes Using Unsupported Nanoporous Gold Catalyst
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We have demonstrated that the unsupported nanoporous gold (AuNPore) was a green and highly efficient heterogeneous catalyst for the reduction of amides to amines using hydrosilanes as reductants. A variety of tertiary amides with a broad functional groups were reduced to the corresponding tertiary amines in the presence of 2 mol% of AuNPore and PheMe2SiH or (Me2SiH)2O under mild conditions. AuNPore catalyst was recovered by simple filtration and used for twelve times without any loss of catalytic activity. The AuNPore/hydrosilane system was also successfully applied to the hydrosilative reduction of sulfoxides and N-oxides. (Figure presented.).
- Zhao, Yuhui,Zhang, Sheng,Yamamoto, Yoshinori,Bao, Ming,Jin, Tienan,Terada, Masahiro
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supporting information
p. 4817 - 4824
(2019/10/28)
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- A new route to N-aromatic heterocycles from the hydrogenation of diesters in the presence of anilines
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The hydrogenation of dicarboxylic acids and their esters in the presence of anilines provides a new synthesis of heterocycles. [Ru(acac)3] and 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) gave good to excellent yields of the cyclic amines at 220 °C. When aqueous ammonia was used with dimethyl 1,6-hexadienoic acid, ?-caprolactam was obtained in good yield. A side reaction involving alkylation of the amine by methanol was suppressed by using diesters derived from longer chain and branched alcohols. Hydrogenation of optically pure diesters (dimethyl (R)-2-methylbutanedioate and dimethyl (S)-2-methylbutanedioate) with aniline afforded racemic 3-methyl-1-phenylpyrrolidine in 78% yield.
- Shi, Yiping,Kamer, Paul C. J.,Cole-Hamilton, David J.,Harvie, Michelle,Baxter, Emma F.,Lim, Kate J. C.,Pogorzelec, Peter
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p. 6911 - 6917
(2017/10/05)
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- BippyPhos: A single ligand with unprecedented scope in the Buchwald-Hartwig amination of (hetero)aryl chlorides
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Over the past two decades, considerable attention has been given to the development of new ligands for the palladium-catalyzed arylation of amines and related NH-containing substrates (i.e., Buchwald-Hartwig amination). The generation of structurally diverse ligands, by research groups in both academia and industry, has facilitated the accommodation of sterically and electronically divergent substrates including ammonia, hydrazine, amines, amides, and NH heterocycles. Despite these achievements, problems with catalyst generality persist and access to multiple ligands is necessary to accommodate all of these NH-containing substrates. In our quest to address this significant limitation we identified the BippyPhos/[Pd(cinnamyl)Cl]2 catalyst system as being capable of catalyzing the amination of a variety of functionalized (hetero)aryl chlorides, as well as bromides and tosylates, at moderate to low catalyst loadings. The successful transformations described herein include primary and secondary amines, NH heterocycles, amides, ammonia and hydrazine, thus demonstrating the largest scope in the NH-containing coupling partner reported for a single Pd/ligand catalyst system. We also established BippyPhos/ [Pd(cinnamyl)Cl]2 as exhibiting the broadest demonstrated substrate scope for metal-catalyzed cross-coupling of (hetero)aryl chlorides with NH indoles. Furthermore, the remarkable ability of BippyPhos/[Pd(cinnamyl)Cl] 2 to catalyze both the selective monoarylation of ammonia and the N-arylation of indoles was exploited in the development of a new one-pot, two-step synthesis of N-aryl heterocycles from ammonia, ortho- alkynylhalo(hetero)arenes and (hetero) aryl halides through tandem N-arylation/hydroamination reactions. Although the scope in the NH-containing coupling partner is broad, BippyPhos/[Pd(cinnamyl)Cl]2 also displays a marked selectivity profile that was exploited in the chemoselective monoarylation of substrates featuring two chemically distinct NH-containing moieties.
- Crawford, Sarah M.,Lavery, Christopher B.,Stradiotto, Mark
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supporting information
p. 16760 - 16771
(2014/01/06)
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- Pt-Sn/γ-Al2O3-catalyzed highly efficient direct synthesis of secondary and tertiary amines and imines
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Versatile syntheses of secondary and tertiary amines by highly efficient direct N-alkylation of primary and secondary amines with alcohols or by deaminative self-coupling of primary amines have been successfully realized by means of a heterogeneous bimetallic Pt-Sn/γ-Al2O3 catalyst (0.5 wt % Pt, Pt/Sn molar ratio=1:3) through a borrowing-hydrogen strategy. In the presence of oxygen, imines were also efficiently prepared from the tandem reactions of amines with alcohols or between two primary amines. The proposed mechanism reveals that an alcohol or amine substrate is initially dehydrogenated to an aldehyde/ketone or NH-imine with concomitant formation of a [PtSn] hydride. Condensation of the aldehyde/ketone species or deamination of the NH-imine intermediate with another molecule of amine forms an N-substituted imine which is then reduced to a new amine product by the in-situ generated [PtSn] hydride under a nitrogen atmosphere or remains unchanged as the final product under an oxygen atmosphere. The Pt-Sn/γ-Al2O 3 catalyst can be easily recycled without Pt metal leaching and has exhibited very high catalytic activity toward a wide range of amine and alcohol substrates, which suggests potential for application in the direct production of secondary and tertiary amines and N-substituted imines.
- He, Wei,Wang, Liandi,Sun, Chenglin,Wu, Kaikai,He, Songbo,Chen, Jiping,Wu, Ping,Yu, Zhengkun
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experimental part
p. 13308 - 13317
(2012/02/02)
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- New classes of antimuscarinic agents endowed with selective antispasmodic properties. 1-Arylsulfonyl pyrrolidin-2-ones and 2-thiones, 1-arylsulfonyl piperidin-2-ones and 2-thiones and 1-arylsulfonyl hexahydro-2H-azepin-2-one
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A series of 1-arylsulfonylpyrrolidin-2-ones (and 2-thiones), 1-aryl sulfonylpiperidin-2-ones (and 2-thiones) and 1-arylsulfonyl hexahydro-2H-azepin-2-one were synthesized and submitted to a battery of binding assays. The compounds showed little or no affinity for the receptors tested other than muscarinic receptors labelled either with [3H]pirenzepine or with [3H]quinuclidinyl benzilate. When tested in the isolated guinea pig ileum, they antagonized the contractions induced by acetylcholine and behaved as competitive muscarinic antagonists. After parenteral administration in mice, most compounds inhibited carbachol-induced diarrhoea but were less effective in counteracting salivation and lacrimation and showed little or no mydriatic action, thus displaying selectivity at the intestinal level. The reference drugs tested, atropine, butyl scopolamine and cimetropium bromide were far less selective. Maximal in vivo activity was obtained by introducing diethylamino or 1-piperidino or 1-hexahydroazepinyl groups in the 4-position of the phenyl ring while the enlargement of a 5- to a 6-membered lactam ring or its conversion into a thiolactam had a less marked effect. The most interesting compounds were further evaluated for their ability to antagonize carbachol-induced colonic hypermotility in the rat and arecoline-induced analgesia in mice. The effect on gastric acid secretion in the rat was also investigated. The overall in vivo data showed that compounds 14, 15, 26 and 27, i.e. those bearing a 1-hexahydroazepinyl group in the 4-position of the phenyl ring, were the most potent and selective compounds. Unlike the reference drugs, they antagonized carbachol-induced diarrhoea and colonic hypermotility at doses (0.6-4 mg/kg i.p.) 1-2 orders of magnitude lower than those needed to counteract carbachol-induced salivation and lacrimation or to induce mydriatic and antisecretory effects. The novelty of these structures and their selectivity of action on smooth muscle are the two key features of this class of antimuscarinics.
- Toja,Parini,Bonetti,Hunt,Fortin,Barzaghi,Cesana,Maggioni,Nencioni,Galliani
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p. 501 - 509
(2007/10/02)
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- 1-ARYLSULPHONYL-2-PIPERIDINONE DERIVATIVES, PROCESS AND INTERMEDIATES FOR THE PREPARATION THEREOF, THEIR APPLICATION AS ANTISPASMODICS AND COMPOSITIONS CONTAINING THEM
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The invention relates to the products of formula STR1 in which R represents the radical STR2 in which R 1 at any position on the benzene ring represents linear, branched or cyclic alkyl, alkenyl or alkynyl containing up to 8 carbon atoms, or the radical S
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