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Journal of Organic Chemistry

Soukaina Faarasse, Saïd El Kazzouli, Franck Suzenet, Gérald Guillaumet
Direct C3-arylation of 1H-pyrazolo[4,3-b]pyridines and direct C3-arylation of 2H-pyrazolo[4,3-b]pyridines in water have been developed. New protocol for sequential C3-arylation procedure on a mixture of 1H- and 2H-pyrazolo[4,3-b]pyridines followed by in situ PMB cleavage has also been achieved. This procedure led to unprotected (NH) C3-arylated 1H-pyrazolo[4,3-b]pyridines in good yields.
September 21, 2018: Journal of Organic Chemistry
Rui Ding, Yongguo Liu, Mengru Han, Wenyi Jiao, Jiaqi Li, Hongyu Tian, Baoguo Sun
The preparation of nitriles from primary amides or aldoximes was achieved by using oxalyl chloride with a catalytic amount of dimethyl sulfoxide in the presence of Et3N. The reactions were complete within 1 h after addition at room temperature. A diverse range of cyano compounds were obtained in good to excellent yields, including aromatic, hetreoaromatic, cyclic and acyclic aliphatic species.
September 21, 2018: Journal of Organic Chemistry
K Naresh Babu, Nikhil Raj Kariyandi, Saina Saheeda M K, Lakshmana Kumar Kinthada, Alakesh Bisai
Metal triflate catalyzed reactions of 3-hydroxy-2-oxindoles with a variety of malonate have been developed under mild condition. The reaction affords a variety of 2-oxindoles sharing a C-3 quaternary center at the pseudobenzylic position in an operationally simple procedure. Control experiments using enantioenriched 3-hydroxy/methoxy 2-oxindoles (91% ee) afforded malonate addition product in racemic form, clearly suggesting that the reaction proceeds through in situ generated 2H-indol-2-one intermediate (4a)...
September 21, 2018: Journal of Organic Chemistry
Peng-Wei Xu, Chen Chen, Jia-Kuan Liu, Yu-Ting Song, Feng Zhou, Jun Yan, Jian Zhou
A Sc(OTf)3 catalyzed highly diastereoselective one-pot sequential [3+3] dipolar cycloaddition reaction of aldehyde or ketone, N-alkyl hydroxylamine and spirocyclopropyl oxindole is developed, allowing facile construction of spirocyclic oxindole-tetrahydro-1,2-oxazines in sufficient structural diversity. The corresponding catalytic enantioselective one-pot protocol of aldehydes is also reported, affording the desired adducts in up to 97% ee. The biological evaluation of selected oxindole-based spirocyclic tetrahydro-1,2-oxazines revealed that they exerted cytotoxic effects on human prostate cancer cells with the capacity to inhibit NFκB signaling in prostate cancer cells...
September 21, 2018: Journal of Organic Chemistry
Hui Peng, Wenkun Luo, Huanfeng Jiang, Biaolin Yin
Herein we report a one-pot protocol for the synthesis of dispiroacetals 4 bearing a cyclobutane motif via tandem Achmatowicz rearrangement and acetalization of 1-[5-(hydroxyalkyl)-furan-2-yl]-cyclobutanols 3 with m-CPBA as the oxidant and AgSbF6 as an additive to promote the cyclization step in an aqueous medium. Dispiroacetals 4 could subsequently undergo Lewis acid-catalyzed ring expansion and skeletal rearrangement to afford 6,7-dihydro-5H-benzofuran-4-ones 5.
September 21, 2018: Journal of Organic Chemistry
Yan He, Zhi Zheng, Qimeng Liu, Guixian Song, Nan Sun, Xinyuan Chai
An efficient and regio-selective synthesis of 2-ene-1,4-diones, 4-hydroxycyclopent- 2-en-1-ones or 2-(furan-3-yl)acetamides is successfully realized through palladium-catalyzed one-pot multi-component reactions of allenols with aryl iodides and carbon monoxide in the presence of tertiary amines. Interestingly, the selectivity is depended on the substitution patterns of the allenol substrates. To be specific, from the reaction of allenols with no substituent attached on the internal position of the allenic moiety, 2-ene-1,4-diones or 4-hydroxycyclopent-2-en-1-ones were formed selectively through carbonylation of aryl iodide followed by acylation of allenol with the in situ formed acyl palladium species, β-hydride elimination of the in situ formed allyl palladium complex, and further tautomerization or intramolecular Aldol reaction...
September 21, 2018: Journal of Organic Chemistry
Shweta Sharma, Mukesh Kumar, Ram A Vishwakarma, Mahendra K Verma, Parvinder Pal Singh
Herein, we report an original one-step, simple, room-temperature, regio-selective Minisci reaction for the acylation of electron-deficient heteroarenes with alkynes. The method has broad functional group compatibility and gives exclusively mono-acylated products in good to excellent yields. The mechanistic pathway has been analyzed based on a series of experiments confirming the involvement of a radical pathway. The 18O-labeling experiment suggested that water is a source of oxygen in the acylated product and head space GC-MS experiment shows the C-C cleavage occurs via release as CO2...
September 21, 2018: Journal of Organic Chemistry
Weiwei Lv, Jia Yu, Bailu Ge, Si Wen, Guolin Cheng
A palladium-catalyzed three-component reaction of aryl iodides, norbornenes, and hexamethyl-disilane/hexamethyldigermane has been developed for the assembly of highly functionalized disilanes/digermanes. The potential synthetic utility of this methodology was highlighted by the late-stage manipulations of natural products and the iterative C-H bis-silylation for the synthesis of highly decorated arenes.
September 21, 2018: Journal of Organic Chemistry
Jing Guo, Wu Qiaolei, Ying Xie, Jiang Weng, Gui Lu
A straightforward method for the visible-light-mediated decarboxylative benzylation of imines is reported. The key feature of this method is the use of simple primary, secondary and tertiary arylacetic acids as precursors of benzyl radicals, enabling the facile benzylation of a variety of imines under mild conditions. A variety of structurally diverse β-arylethylamine amines (37 examples) have been accessed using this method.
September 21, 2018: Journal of Organic Chemistry
Francesco Berti, Andrea Menichetti, Lucilla Favero, Fabio Marchetti, Mauro Pineschi
The particular nature of tetrahydropyrido[4,3- e]-1,4,2-dioxazines of type 1 allows the regio- and stereoselective obtainment of substituted N-carbamoyl tetrahydropyridines by common reducing agents. A completely novel, biologically active, bicyclic 1,3-diaza-4-oxa-[3.3.1]-nonene scaffold can be generated by the use of lithium triethylborohydride through unprecedented cascade syn-SN 2' reduction/carbamate reduction/cyclization reactions. The remarkable regioselectivity switches in the allylic reduction process have been rationalized with the aid of computational studies...
September 21, 2018: Journal of Organic Chemistry
Xiaowei Wu, Haitao Ji
A robust Ru(II)-catalyzed C-H allylation of electron-deficient alkenes with allyl alcohols in aqueous solution is reported. This method provides a straightforward and efficient access to the synthetically useful 1,4-diene skeletons. With the assistance of the N-methoxycarbamoyl directing group, this allylation reaction features a broad substrate scope with good functional group tolerance, excellent regio- and stereoselectivity, absence of metal oxidants, water-tolerant solvents, and mild reaction conditions...
September 21, 2018: Journal of Organic Chemistry
Tubai Ghosh, Pintu Maity, Brindaban C Ranu
An efficient method for the C(sp2 ) amidation of 8-aminoquinoline benzamide by acyl azide in the presence of copper acetate has been achieved via C-H activation. Interestingly, the loading of copper acetate has a strong influence on the outcome of the reaction. The use of 1 equiv of copper acetate produces the corresponding aroyl amide, whereas the use of 2 equiv led to acetyl amide. A series of substituted benzoyl and acetyl amides has been obtained.
September 21, 2018: Journal of Organic Chemistry
Jin-Tao Yu, Rongzhen Chen, Hailang Jia, Changduo Pan
Enone carbonyl directed 1,4-addition of ortho-C-H bond in chalcones to maleimides was developed under the catalysis of Rh(III). This reaction furnished a variety of chalcone-based pharmacologically useful 3-arylated succinimide derivatives in good yields with excellent selectivity.
September 21, 2018: Journal of Organic Chemistry
Juliette Halli, Philipp Kramer, Jennifer Grimmer, Michael Bolte, Georg Manolikakes
A highly modular, diastereoselective one-pot-synthesis of 1,3-diamines with three contiguous stereogenic centers is reported. Our method provides a fast and efficient access to 1,2- anti-2,3- anti-1,3-diamines from three readily available building blocks. This Bi(OTf)3 -catalyzed reaction is insensitive to air and moisture and can be performed on a multigram scale.
September 21, 2018: Journal of Organic Chemistry
Sachin R Shirsath, Ganesh H Shinde, Aslam C Shaikh, M Muthukrishnan
BF3 ·OEt2 catalyzed 1,6-conjugate addition of tert-butyl isocyanide to para-quinone methides and fuchsones for the synthesis of α-diaryl and α-triaryl nitriles has been reported. This protocol allows α-diaryl- and α-triaryl nitriles to be accessed in good to excellent yields and with a broad substrate scope, which could be further functionalized to give a versatile set of products. This is the first example wherein tert-butyl isocyanide has been used as a cyanide source for the 1,6-conjugate addition.
September 21, 2018: Journal of Organic Chemistry
Theeranon Tankam, Jakkrit Srisa, Mongkol Sukwattanasinitt, Sumrit Wacharasindhu
In this work, we developed a catalyst-free amination of 2-mercaptobenzoxazoles on water under microwave irradiation. The product, 2-aminobenzoxazoles, was successfully produced via direct amination with various amines in moderate to high yields. The formal synthesis of Suvorexant, a medication for the treatment of insomnia, was accomplished using a developed amination process. The reaction was completed in an hour at 100-150 °C in a microwave reactor without the use of external catalyst or additive. Key benefits of this process include an on-water reaction, short reaction time, being scalable and catalyst-free, and use of 2-mercaptobenzoxazoles as an inexpensive starting material having low environmental impact in its preparation...
September 21, 2018: Journal of Organic Chemistry
Josiah J Newton, Robert Britton, Chadron Mark Friesen
Here we report a convenient synthesis of thionoesters by base-catalyzed transesterification. Aryl and alkyl thionobenzoates and thionoheterobenzoates were efficiently prepared using various alcohols catalyzed by the corresponding sodium alkoxide. This methodology features a broad substrate scope, good to excellent yields, short reaction times, while simultaneously driving the reaction towards completion through the removal of the methanol byproduct. We also report the conversion of a small collection of thionobenzoates into the corresponding α,α-difluorobenzyl ethers to demonstrate the conversion of alcohols into difluorobenzyl or difluoroheterobenzyl ethers, a process that could prove useful for lead optimization in medicinal chemistry...
September 20, 2018: Journal of Organic Chemistry
Haiyong Zhu, Chao Chen, Dan Li, Pengxin Wang, Yuan Wang, Lutao Bai, Dongxu Yang, Linqing Wang
A copper(II) trifluoromethanesulfonate proceeded Prins reaction between salicylaldehydes and allyl alcohols is realized under mild conditions. A series of compounds containing dioxa-benzobicyclo[3.2.1] octane motifs are obtained in moderate to good yields. The current method can efficiently construct the valuable structural motif form easily accessed starting materials, providing a smooth method to build benzobicyclo skeletons.
September 20, 2018: Journal of Organic Chemistry
Wangze Song, Ming Li, Nan Zheng, Karim Ullah, Junhao Li, Kun Dong, Yubin Zheng
A highly regio- and diastereoselective method to access cis-2,6-disubstituted dihydropyridinones under mild conditions by an iridium-catalyzed allylic etherification is reported. cis-2,6-Disubstituted dihydropyridinones are important precursors for the de novo synthesis of the corresponding piperidine alkaloids and iminosugars. This strategy features a broad substrate scope, high yields and excellent regio- and diastereoselectivities. A π-allyl-Ir intermediate is involved in the mechanism. The strong A1,3-strain from the tosyl group may also favor the formation of cis-products in this transformation...
September 20, 2018: Journal of Organic Chemistry
Tianyu Jiao, Guangcheng Wu, Liang Chen, Cai-Yun Wang, Hao Li
A series of tetrahedral cages and triangular prisms, have been self-assembled by condensing ostensibly analogous trisformyl precursors with tris or bisamino linkers under the nominally reversible reaction conditions in the manner of either [4+4] or [2+3], respectively. We observed that the conformations of the trisformyl precursors have great impact on the self-assembly pathway and product yields. More specifically, a rigid and planar precursor favors the formation of prisms while a more twisted one favors tetrahedron...
September 20, 2018: Journal of Organic Chemistry
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