- Decarbonylation through Aldehydic C-H Bond Cleavage by a Cationic Iridium Catalyst
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We report the decarbonylation of aldehydes through an aldehydic C-H bond cleavage catalyzed by a cationic iridium/bisphosphine catalyst. The reaction proceeds under relatively mild conditions to give the corresponding hydrocarbon products in moderate to high yields. In addition, this cationic iridium catalyst system can be applied to an asymmetric hydroacylation of ketones.
- Shirai, Tomohiko,Sugimoto, Kazuki,Iwasaki, Masaya,Sumida, Ryuki,Fujita, Harunori,Yamamoto, Yasunori
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p. 972 - 976
(2019/05/10)
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- Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum
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The volatiles emitted by the ascomycetes Hypoxylon griseobrunneum and Hypoxylon macrocarpum (Hypoxylaceae, Xylariales) were collected by use of a closed-loop stripping apparatus (CLSA) and analysed by GC-MS. The main compound class of both species were polysubstituted benzene derivatives. Their structures could only be unambiguously determined by comparison to all isomers with different substitution patterns. The substitution pattern of the main compound from H. griseobrunneum, the new natural product 2,4,5-trimethylanisole, was explainable by a polyketide biosynthesis mechanism that was supported by a feeding experiment with (methyl-2H3)methionine.
- Rinkel, Jan,Babczyk, Alexander,Wang, Tao,Stadler, Marc,Dickschat, Jeroen S.
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p. 2974 - 2990
(2019/01/05)
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- Design, synthesis, biological activities and DFT calculation of novel 1,2,4-triazole Schiff base derivatives
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Series of 1,2,4-triazole Schiff bases (2a-2d, 2f-2h and 3a-3h) have been designed and synthesized. The structure of title compounds was confirmed on the basis of their spectral data and elemental analysis. All the target compounds were screened for their in vitro antifungal activity and antibacterial activity. Two of the tested compounds (2a and 2b) exhibited significant antifungal activity against most fungi, especially compound 2a showed better antifungal activity than triadimefon. Meanwhile, the antibacterial activity assay also indicated compound 2a exhibited excellent antibacterial activities comparable to chloramphenicol. The SAR manifested no substitution at position 5 of the triazole ring caused an increase in activity, and 3-phenoxy phenyl group introduced in 1,2,4-triazole scaffold can enhance the antibacterial activity. The DFT calculation indicated triazole ring, S atom and benzene ring in both of the 2a and 3a make a major contribution to the activity.
- Jin, Ru-Yi,Zeng, Chu-Yue,Liang, Xu-Hua,Sun, Xiao-Hong,Liu, Yuan-Fa,Wang, Yan-Yan,Zhou, Sha
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p. 253 - 260
(2018/07/06)
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- Methylation of phenol and its derivatives with dimethyl carbonate in the presence of Mn2(CO)10, W(CO)6, and Co2(CO)8
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Aryl methyl ethers were synthesized by reactions of phenol, substituted phenols, and α- and β-naphthols with dimethyl carbonate in the presence of manganese, tungsten, and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of aryl methyl ethers.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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p. 330 - 334
(2015/05/04)
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- Tailoring 3,3'-dihydroxyisorenieratene to hydroxystilbene: Finding a resveratrol analogue with increased antiproliferation activity and cell selectivity
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Four novel compounds were designed by "tailoring" 3,3'-dihydroxyisorenieratene (a natural carotenoid) based on an isoprene unit retention truncation strategy. Among them, the smallest molecule 1 (2,3,6,2',3',6'-hexamethyl-4,4'-dihydroxy-trans-stilbene) was concisely synthesized in a one-pot Stille-Heck tandem sequence, and surfaced as a promising lead molecule in terms of its selective antiproliferative activity mediated by blocking the NCI-H460 cell cycle in G1 phase. Additionally, theoretical calculations and cell uptake experiments indicate that the unique polymethylation pattern of compound 1 significantly induces a conformational change shift out of planarity and increases its cell uptake and metabolic stability. The observation should be helpful to rationally design resveratrol-inspired antiproliferative agents. Four novel compounds were designed by "tailoring" 3,3'-dihydroxyisorenieratene (a natural carotenoid) based on an isoprene unit retention truncation strategy. Among them, the smallest molecule 1 was concisely synthesized by a one-pot Stille-Heck tandem sequence, and surfaced as a promising lead molecule in terms of its selective antiproliferative activity (see figure).
- Kang, Yan-Fei,Yan, Wen-Jing,Zhou, Ting-Wen,Dai, Fang,Li, Xiu-Zhuang,Bao, Xia-Zhen,Du, Yu-Ting,Yuan, Cui-Hong,Wang, Hai-Bo,Ren, Xiao-Rong,Liu, Qiang,Jin, Xiao-Ling,Zhou, Bo,Zhang, Jie
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supporting information
p. 8904 - 8908
(2014/07/22)
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- One-pot synthesis of pyrimidinothiazolidinones and their anti-inflammatory and antimicrobial studies
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In the present investigation, we report a one-pot synthesis of the title compounds, 2-arylidene-5-(2,3,6-trimethyl-4-methoxyphenyl)-7-substituted-5H- pyrimidino-[2,3-b]thiazolidine-3-ones 6a-j and 2-(5-nitro-2-thienylidine)-5-(2, 3,6-trimethyl-4-methoxyphenyl)-7-substituted-5H- pyrimidino-[2,3-b]thiazolidine- 3-ones 7a-e. Thus, 6a-j and 7a-e were prepared in good yields by refluxing 4-(2,3,6-trimethyl-4-methoxyphenyl)-6-methyl/aryl-3,4-dihydropyrimidin-2-(1H) -thiones 5, monochloro acetic acid, and anhydrous sodium acetate with the appropriate aromatic aldehyde/5-nitro-2-thiophenediacetate in acetic acid/acetic anhydride medium. The structures of these new compounds were established on the basis of their analytical and spectral data. Some of the newly synthesized compounds were screened for their anti-inflammatory and antimicrobial activity. They show moderate anti-inflammatory activity, and some of them were found to be promising antibacterial and antifungal agents. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.
- Lingappa,Sujith,Adhikari, Adithya,Rai, N. Satheesha,Vijaynarayana,Kalluraya, Balakrishna
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scheme or table
p. 501 - 508
(2010/06/12)
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- Advantage of in situ generation of N-arylsulfonyl imines from α-amide sulfones in the phase-transfer-catalyzed asymmetric Strecker reaction
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Highly efficient, catalytic enantioselective synthesis of N-arylsulfonyl α-amino nitriles from the corresponding α-amido sulfones has been achieved under toluene-aqueous potassium cyanide biphasic conditions using chiral quaternary ammonium iodide (R,R,R)-1 as an effective phase-transfer catalyst. This Strecker synthesis involving the in situ generation of the reactive N-sulfonyl imines is advantageous for the cyanation of the substrates having primary and secondary alkyl substituents.
- Ooi, Takashi,Uematsu, Yukitaka,Fujimoto, Jun,Fukumoto, Kazuhiro,Maruoka, Keiji
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p. 1337 - 1340
(2007/10/03)
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- A new stereoselective synthesis of acitretin (=Soriatane, Neotigason)
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A new synthesis of acitretin via a C15 + C5 route is reported. The C15 unit is the key step, involving a procedure that provides the required (all-E)-C15-aldehyde with high stereoselectivity.
- Andriamialisoa, Zo,Valla, Alain,Cartier, Dominique,Labia, Roger
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p. 2926 - 2929
(2007/10/03)
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- Evaluation of retinoid lactones as topical therapeutic agents in dermatology
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Purpose. Optimization of the therapeutic ratio of analogs of the topically active 11-cis,13-cis-12-hydroxymethylretinoic acid, δ-lactone (I) relative to antihyperproliferation and antihyperkeratinization vs. toxicity. Methods. Nine analogs of 1, in which variations were made in the lipophilic cyclohexenyl moiety or in the lactone ring, were evaluated for topical activity against hyperkeratinization, inhibition of TPA-induced DNA synthesis and for skin irritation. Results. Although more potent lactones than the parent lactone 1 were identified, none possessed the favorable therapeutic ratio associated with 1. Conclusions. The δ-lactone 1 possesses unique molecular features responsible for its desirable therapeutic ratio as an anti-hyperproliferative and antihyperkeratotic agent. In view of its very low systemic retinoid toxicity and the absence of any systemic toxicity, this lactone may be a good candidate for use in the topical treatment of acne.
- Lewin,Black,Bos,Goehring,Nair,Whiting,Bouquin,Tetrault,Carroll
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p. 983 - 992
(2007/10/03)
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- STEREOSELECTIVE SYNTHESIS OF 5-ARYL-3-METHYL-2E,4E-PENTADIENALS
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A series of 5-aryl-3-methyl-2E,4E-pentadienals were synthesized stereoselectively from 4-aryl-3E-buten-2-ones and methylmagnesium iodide followed by formylation of the obtained tertiary dimethylstyrylcarbinols by the formylating complex produced from dimethylformamide and phosphorus oxychloride.A synthesis of 2,3,6-trimethyl-4-methoxybenzaldehyde, starting from pseudocumene, is proposed.
- Makin, S. M.,Mikerin, I. E.,Dobretsova, E. K.,Shavrygina, O. A.
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p. 572 - 575
(2007/10/02)
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- REACTION OF 1,2,4-TRIMETHYLBENZENE WITH PERACETIC ACID
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The oxidation of 1,2,4-trimethylbenzene with peracetic acid leads to the formation of trimethylphenols and hydroquinones, which undergo transformations to the corresponding benzoquinones and products from oxidative cleavage of the ring.The controlling stage of the process is the electrophilic hydroxylation of 1,2,4-trimethylbenzene.
- Kharchuk, V. G.,Kolenko, I. P.,Petrov, L. A.,Gus'kova, L. M.
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p. 2071 - 2078
(2007/10/02)
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- Method for protecting amino group and restoring the same
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An ω-amino group and/or α-amino group in an amino acid or a peptide can be protected with a 4-methoxy-2,3,6-trimethylbenzenesulfonyl group, and said group may easily be removed without affecting the amino acid or the peptide. Thus, the present invention is useful in the synthesis of peptide containing ω-amino group and/or α-amino group.
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- Method for protecting guanidino group and restoring the same
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A guanidino group in an amino acid or a peptide can be protected with a specific group, i.e. pentamethylbenzensulfonyl, 2,4,6-trimethoxybenzenesulfonyl, 4-methoxy-2,3,5,6-tetramethylbenzenesulfonyl, 4-methoxy-2,6-dimethylbenzenesulfonyl or 4-methoxy-2,3,6-trimethylbenzenesulfonyl, and said group may easily be removed without affecting the amino acid or the peptide to be derived from the protected amino acid or peptide. Thus, the present invention is useful in the synthesis of peptides containing the guanidino group.
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- Further Studies on the Use of Multi-substituted Benzenesulfonyl Groups for Protection of the Guanidino Function of Arginine
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Various multi-substituted benzenesulfonyl protecting groups for the guanidino function of arginine, removable under mild conditions such as with trifluoroacetic acid (TFA)-thioanisole, were studied.Among them, the 4-methoxy-2,6-dimethylbenzenesulfonyl (Mds) group, the 2,3,4,5,6-pentamethylbenzenesulfonyl (Pme) group, and the 4-methoxy-2,3,6-trimethylbenzenesulfonyl (Mtr) group were found to be useful.Both Mds and Pme show considerable resistance to TFA and, therefore, are suitable for procedures in which the intermediates are deprotected by TFA treatment, while Mtr is the most useful protecting group when TFA treatment is not necessary.Keywords---4-methoxy-2,6-dimethylbenzenesulfonyl (Mds); 2,4,6-trimethoxybenzenesulfonyl (Mtb); 2,3,4,5,6-pentamethylbenzenesulfonyl (Pme); 4-methoxy-2,3,6-trimethylbenzenesulfonyl (Mtr); trifluoroacetic acid-thioanisole deprotection
- Fujino, Masahiko,Wakimasu, Mitsuhiro,Kitada, Chieko
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p. 2825 - 2831
(2007/10/02)
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