- Photo-on-Demand Synthesis of Chloroformates with a Chloroform Solution Containing an Alcohol and Its One-Pot Conversion to Carbonates and Carbamates
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Chloroformates are key reagents for synthesizing carbonates and carbamates. The present study reports a novel photo-on-demand in situ synthesis of chloroformates with a CHCl3 solution containing a primary alkyl alcohol. It further allowed the one-pot synthesis of carbonates and carbamates through subsequent addition of alcohols or amines, respectively.
- Liang, Fengying,Suzuki, Yuto,Tsuda, Akihiko,Yanai, Masaki
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supporting information
(2020/04/21)
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- Versatile Cp*Co(III)(LX) Catalyst System for Selective Intramolecular C-H Amidation Reactions
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Herein, we report the development of a tailored cobalt catalyst system of Cp*Co(III)(LX) toward intramolecular C-H nitrene insertion of azidoformates to afford cyclic carbamates. The cobalt complexes were easy to prepare and bench-stable, thus offering a convenient reaction protocol. The catalytic reactivity was significantly improved by the electronic tuning of the bidentate LX ligands, and the observed regioselectivity was rationalized by the conformational analysis and DFT calculations of the transition states. The superior performance of the newly developed cobalt catalyst system could be broadly applied to both C(sp2)-H and C(sp3)-H carbamation reactions under mild conditions.
- Chang, Sukbok,Jung, Hoimin,Kim, Dongwook,Lee, Jeonghyo,Lee, Jia,Park, Juhyeon
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supporting information
p. 12324 - 12332
(2020/08/06)
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- PROCESS FOR PRODUCING CHLOROFORMATE COMPOUND
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The present invention provides a method for safely producing a large amount of chloroformate compound with high yield. The chloroformate compound can be produced by mixing and reacting a solution of triphosgene, an amine and an alcohol compound in a flow reactor. The chloroformate compound can also be produced by mixing and reacting a solution of triphosgene with a solution comprising an amine and an alcohol compound in a flow reactor. The amine is preferably tributylamine, and preferably used in an amount of 0.8 to 3 equivalents relative to an amount of the alcohol compound.
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Paragraph 0051-0052; 0060-0067
(2019/06/20)
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- Safe and Efficient Phosgenation Reactions in a Continuous Flow Reactor
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Phosgene is widely used in organic synthesis owing to its high reactivity, utility, and cost efficiency. However, the use of phosgene in batch processes on the industrial scale is challenging owing to its toxicity. An effective method to minimize reaction volumes and mitigate the safety risks associated with hazardous chemicals is the use of flow reactors. Consequently, we have established a flow reaction system using triphosgene and tributylamine, which affords a homogeneous reaction that avoids clogging issues. In addition, we have demonstrated that this methodology can be applied to a wide variety of phosgene reactions, including the preparation of pharmaceutical intermediates, in good to excellent yields.
- Yasukouchi, Hiroaki,Nishiyama, Akira,Mitsuda, Masaru
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supporting information
p. 247 - 251
(2018/02/23)
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- Production and cogeneration N [...] succinimide, N '-di-succinimide-based carbon ester method
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The invention belongs to the field of fine chemical engineering, and particularly relates to a method for producing fluorenylmethoxycarbonylacyl succinimide and coproducing N,N'-disuccinimidocarbonate. The method comprises the following steps: (1) preparation of Fmoc-cl: adding THF (tetrahydrofuran), 9-fluorenylmethanol and an organic amine catalyst into a reaction kettle, cooling to 0-10 DEG C, adding solid phosgene, and completely reacting; (2) preparation of Fmoc-Osu and DSC: adding Hosu, cooling to -5 to +5 DEG C, dropwisely adding a tributyl amine tetrahydrofuran solution, heating to room temperature, and completely reacting; (3) filtering to obtain a DSC crude product; and (4) carrying out mother solution after-treatment to obtain the Fmoc-Osu. A proper amount of 9-fluorenylmethanol is added into the Hosu/solid phosgene/tributyl amine system to quantitatively generate the two products Fmoc-Osu and DSC, wherein the DSC precipitates in the form of crystalline solid, and the Fmoc-Osu and tributyl amine hydrochloride are still dissolved in the tetrahydrofuran solvent; and therefore, the two products can be respectively subjected to filtration, purification and other routine operations to obtain the refined products with the purity of greater than 99%.
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Paragraph 0036-0037
(2017/02/09)
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- Reversal of P-gp and BCRP-mediated MDR by tariquidar derivatives
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Abstract With an aim to generate non-toxic, specific and highly potent multidrug resistance (MDR) modulators, a novel series of anthranilic acid amide-substituted tariquidar derivatives were synthesized. The new compounds were evaluated for their cytotoxicity toward normal human colon fibroblasts (CCD18-Co), human gastric epithelial cell line (HFE) and primary rat liver cells, and for their ability to inhibit P-gp/BCRP-mediated drug efflux and reversal of P-gp and BCRP-mediated MDR in parental and drug-resistant cancer cell lines (LCC6 MDR1, MCF-7 FLV1000, R-HepG2, SW620-Ad300). While tariquidar is highly toxic to normal cells, the new derivatives exhibited much lower or negligible cytotoxicity. Some of the new tariquidar derivatives inhibited both P-gp and BCRP-mediated drug efflux whereas a few of them bearing a sulfonamide functional group (1, 5, and 16) are specific to P-gp. The new compounds were also found to potentiate the anticancer activity of the transporter substrate anticancer drugs in the corresponding transporter-overexpressing cell lines. The extent of resistance reversal was found to be consistent with the transporter inhibitory effect of the new derivatives. To further understand the mechanism of P-gp and BCRP inhibition, the tariquidar derivatives were found to interact with the transporters using an antibody-based UIC2 or 5D3 shift assay. Moreover, the transporters-inhibiting derivatives were found to modulate the ATPase activities of the two MDR transporters. Our data thus advocate further development of the new compounds for the circumvention of MDR.
- Li, Xu-Qin,Wang, Lin,Lei, Yan,Hu, Tao,Zhang, Fei-Long,Cho, Chi-Hin,To, Kenneth K.W.
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p. 560 - 572
(2015/07/28)
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- In vitro radical scavenging and cytotoxic activities of novel hybrid selenocarbamates
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Novel selenocyanate and diselenide derivatives containing a carbamate moiety were synthesised and evaluated in vitro to determine their cytotoxic and radical scavenging properties. Cytotoxic activity was tested against a panel of human cell lines including CCRF-CEM (lymphoblastic leukaemia), HT-29 (colon carcinoma), HTB-54 (lung carcinoma), PC-3 (prostate carcinoma), MCF-7 (breast adenocarcinoma), 184B5 (non-malignant, mammary gland derived) and BEAS-2B (non-malignant, derived from bronchial epithelium). Most of the compounds displayed high antiproliferative activity with GI50 values below 10 μM in MCF-7, CCRF-CEM and PC-3 cells. Radical scavenging properties of the new selenocompounds were confirmed testing their ability to scavenge DPPH and ABTS radicals. Based on the activity of selenium-based glutathione peroxidases (GPxs), compounds 1a, 2e and 2h were further screened for their capacity to reduce hydrogen peroxide under thiol presence. Results suggest that compound 1a mimics GPxs activity. Cytotoxic parameters, radical scavenging activity and ADME profile point to 1a as promising drug candidate.
- Romano, Beatriz,Plano, Daniel,Encío, Ignacio,Palop, Juan Antonio,Sanmartín, Carmen
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p. 1716 - 1727
(2015/03/30)
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- Ureidopeptide-based Bronsted bases: Design, synthesis and application to the catalytic enantioselective synthesis of β-amino nitriles from (arylsulfonyl)acetonitriles
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The addition of cyanoalkyl moieties to imines is a very attractive method for the preparation of β-amino nitriles. We present a highly efficient organocatalytic methodology for the stereoselective synthesis of β-amino nitriles, in which the key to success is the use of ureidopeptide-based Bronsted base catalysts in combination with (arylsulfonyl)acetonitriles as synthetic equivalents of the acetonitrile anion. The method gives access to a variety of β-amino nitriles with good yields and excellent enantioselectivities, and broadens the stereoselective Mannich-type methodologies available for their synthesis. Learning from peptides: A concise route for the catalytic enantioselective synthesis of β-amino nitriles has been achieved by using ureidopeptide-based Bronsted bases as catalysts in the Mannich reaction of N-Boc imines and (arylsulfonyl)acetonitriles (see scheme; Boc=tert-butoxycarbonyl, napht=naphthyl, TMS=trimethylsilyl).
- Diosdado, Saioa,Lopez, Rosa,Palomo, Claudio
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supporting information
p. 6526 - 6531
(2014/06/09)
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- Catalytic enantioselective synthesis of tertiary thiols from 5h-thiazol-4-ones and nitroolefins: Bifunctional ureidopeptide-based bronsted base catalysis
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Fully loaded: The ureidopeptide-based bifunctional Bronsted base 1 efficiently promotes the first direct catalytic Michael reaction of α-mercapto carboxylate surrogates with nitroolefins involving a fully substituted α-carbon atom construction. Copyright
- Diosdado, Saioa,Etxabe, Julen,Izquierdo, Joseba,Landa, Aitor,Mielgo, Antonia,Olaizola, Iurre,Lopez, Rosa,Palomo, Claudio
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supporting information
p. 11846 - 11851
(2013/11/19)
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- Amino acid protecting groups
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This invention relates to compounds of the formula a compound of the formula STR1 wherein X is O, CR7 R8, S or NR9 wherein R7 and R8 are independently hydrogen, or lower alkyl, and R9 is lower alkyl; n is 0 or 1; R1 and R2 are independently hydrogen, lower alkyl, monoorganosilyl, diorganosilyl, triorganosilyl, halogen, aryl, or nitro; R3 is hydrogen, lower alkyl, monoorganosilyl, diorganosilyl, triorganosilyl, halogen, 9-fluorenylalkyl, cycloalkyl, aryl or aralkyl; R4 and R5 are independently hydrogen, lower alkyl, or aryl or one of R4 and R5 is 9-fluorenyl; R6 is H or COZ wherein Z is an amino acid, a peptide residue or a leaving group; and with the provisos that when n is 0 and R3 is hydrogen, R1 and R2 are not hydrogen, halogen or nitro; that when n is 0 and R3 is lower alkyl, R1 and R2 are not hydrogen; and that when X is O or CR7 R8 wherein R7 and R8 are H, that R1, R2, R3, R4, R5, and R6 are not all simultaneously H. The compounds of the present invention are useful in peptide synthesis as blocking or protecting groups for reactive groups. The present invention is also directed to a method of protecting a reactive group of an organic molecule during a reaction which modifies a portion of the molecule other than the protected group.
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- SIMULTANEOUS USE OF N-Fmoc AND OTmse PROTECTIVE GROUPS IN THE SYNTHESIS OF PEPTOLYTIC SENSITIVE PEPTIDES
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The combined use of Fmoc (fluorenylmethoxycarbonyl) as N-protection and Tmse (trimethylsilylethyl) as O-protection during demanding fragment condensation mediated by Bop-Cl (N,N'-bis(3-oxo-2-oxazolidinyl)phosphinyl chloride) has been explored in the preparation of useful synthons that are sensitive to acidic and even basic hydrolyses.Stepwise deprotection by morfoline (Fmoc-deprotection) followed by F--mediated removal of Tmse results in a very effective peptide synthesis strategy, as exemplified by the preparation of i.a.Phg-MePhe-Thz.Similarly, combinations of N-Boc, O-Tmse peptide esters are also possible that allow the preparation of +H2-MePhe-Thz-OTmse (via Boc-MePhe-Thz-OTmse) without competitive DKP formation.
- Vanfleteren, L.,Anteunis, M. J. O.
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p. 505 - 518
(2007/10/02)
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- Synthesis an CuCN-Promoted Cyanation of Iodoformic Esters
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A number of iodoformic esters have been prepared, isolated, and identified for the first time.Phenyl iodoformate has been converted into phenyl cyanoformate under mild conditions.Decarboxylative iodination of iodoformates ROCOIto give RI and CO2 can be slowed down by the choice of the group R.
- Hoffmann, H.M.R.,Iranshahi, Lotfollah
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p. 1174 - 1176
(2007/10/02)
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