- METHOD FOR PRODUCING 1,3-BISACYLOXY-2-METHYLENE PROPANE
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A method for producing a 1,3-bisacyloxy-2-methylenepropane represented by the following general formula (II), including reacting a carboxylic acid represented by the following general formula (I), isobutylene, and oxygen, in a liquid phase, in the presence of a catalyst containing a carrier having carried thereon palladium and a transition metal of Group 11 in the periodic table, and a catalyst activator.
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Paragraph 0097
(2021/11/13)
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- Method for preparing 2-methyl-1, 3-propylene glycol from isobutene
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The invention discloses a method for preparing 2-methyl-1, 3-propylene glycol from isobutene. The method comprises the following steps: mixing isobutene with acetic acid and oxygen, and carrying out an oxyacetylation reaction under the action of a supported palladium-molybdenum catalyst to obtain 2-methylene propane-1, 3-diacetoxy, namely a compound (C); carrying out transesterification on the compound (C) under the action of a basic catalyst to obtain 2-methylene-1, 3-propylene glycol, namely a compound (D); and carrying out hydrogenation reaction on the compound (D) to obtain the 2-methyl-1,3-propylene glycol. According to the method, the 2-methyl-1, 3-propylene glycol can be generated with high selectivity, and the whole process is high in atom utilization rate, environmentally friendly and suitable for large-scale industrial application.
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Paragraph 0054-0056; 0058; 0064-0065; 0067-0068; 0070-0071;
(2021/02/10)
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- METHOD FOR PRODUCING BIS-ACYLOXYLATED EXOMETHYLENE COMPOUND
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A method of producing a bis-acyloxylated exomethylene compound represented by general formula (III), including reacting a monoacyloxylated exomethylene compound represented by general formula (I), a carboxylic acid represented by general formula (II), and oxygen in a liquid phase in the presence of a catalyst and optionally a solvent:
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Paragraph 0101; 0109-0115
(2020/09/22)
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- Synthetic method of huperzine A
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The invention belongs to the technical field of medicine synthesis and particularly relates to a synthetic method of huperzine A. The method includes twelve steps of reactions, 1,4-dioxaspiro[4.5]decan-8-one being a raw material, so that the chemical synthesis of the huperzine A is completed at a high total yield. The method is fewer in reaction steps, is simple in operations, has high yield, is stable in intermediates and gentle in reaction conditions, and is easy to control in reactions.
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Paragraph 0075-0081
(2019/05/15)
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- Synthesis of gem-Difluoromethylene Containing Cycloalkenes via the Ring-Opening Reaction of gem-Difluorocyclopropanes and Subsequent RCM Reaction
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The radical-type ring-opening reaction of gem-difluorocyclopropanes and subsequent regioselective monoepoxidation of the products were demonstrated. Introduction of a vinyl or allyl group to the epoxide produced the diene derivatives that were subjected to the ring closing metathesis reaction to furnish the gem-difluoromethylene containing cyclopentene, cycloheptene, and cyclooctene derivatives in good to excellent yields.
- Masuhara, Yoshihiro,Tanaka, Toshiki,Takenaka, Hiroaki,Hayase, Shuichi,Nokami, Toshiki,Itoh, Toshiyuki
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p. 5440 - 5449
(2019/05/01)
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- Assembly of Terpenoid Cores by a Simple, Tunable Strategy
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Oxygenated, polycyclic terpenoid natural products have important biological activities. Although total synthesis of such terpenes is widely studied, synthetic strategies that allow for controlled placement of oxygen atoms and other functionality remains a challenge. Herein, we present a simple, scalable, and tunable synthetic strategy to assemble terpenoid-like polycycloalkanes from cycloalkanones, malononitrile, and allylic electrophiles, abundantly available reagent classes.
- Lahtigui, Ouidad,Emmetiere, Fabien,Zhang, Wei,Jirmo, Liban,Toledo-Roy, Samira,Hershberger, John C.,Macho, Jocelyn M.,Grenning, Alexander J.
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p. 15792 - 15796
(2016/12/16)
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- The preparation of trisubstituted alkenyl nucleoside phosphonates under ultrasound-assisted olefin cross-metathesis
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Intermolecular ultrasound-assisted olefin cross-metathesis is reported. This approach allows an easy access to challenging trisubstituted alkenyl nucleoside phosphonates. Regioselective chemoenzymatic deacetylation and Mitsunobu coupling are also describe
- Sari, Ozkan,Hamada, Manabu,Roy, Vincent,Nolan, Steven P.,Agrofoglio, Luigi A.
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supporting information
p. 4390 - 4393
(2013/09/24)
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- Synthesis of isofagomine and a new C6 pyrrolidine azasugar with potential biological activity
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An efficient asymmetric synthesis of isofagomine, based on a precursor containing three differentiated hydroxyl functions, is described. The side product in the key alkylation step is converted into (2S,3R,4R)-2,4- bis(hydroxymethyl)-3-hydroxypyrrolidine, a new C6 pyrrolidine azasugar, which inhibits α-glucosidase from yeast. Georg Thieme Verlag Stuttgart.
- Espeel, Pieter E. R.,Piens, Kathleen,Callewaert, Nico,Van Der Eycken, Johan
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body text
p. 2321 - 2325
(2009/05/07)
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- Easy access to derivatives of 2-(hydroxymethyl)propane-1,2,3-triol (isoerythritol) with up to four separately addressable functionalities
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5-Methylene-2-oxo[1,3,2]dioxathiane (2) was obtained in 91% yield from 2-methylenepropane-1,3-diol (1) and thionyl chloride. The cyclic sulfite 2 reacts with a variety of nucleophiles to give formally monosubstituted products 3 of the diol 1 in 62-77% yield. Oxidation of 2 with RuCl3/NaIO4 yields the diprotected tetraol 5-(hydroxymethyl)-2,2-dioxo[1,3,2]-dioxathian-5-ol (7) in 86% yield, which can be used to easily access tetrafunctional derivatives of 2-(hydroxymethyl)propane-1,2,3-triol (isoerythritol); for example, acetylation with acetic anhydride furnishes in 96% yield the primary acetate 11, which reacts with potassium cyanide and sodium azide to give the 2-cyano- and 2-(azidomethyl)propane-1,2,3-triol monoacetates 12a,b (78 and 82% yield, respectively). Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Friedrich, Marko,Savchenko, Andrei I.,Waechtler, Andreas,De Meijere, Armin
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p. 2138 - 2143
(2007/10/03)
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- An easy palladium-catalyzed access to substituted 3-methylene-3,4-dihydro-2H-1,5-benzodioxepines
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Palladium-catalyzed condensation of substituted benzene-1,2-diols with the biscarbonate of 2-(hydroxymethyl)allyl alcohol gave the corresponding 3-methylene-3,4-dihydro-2H-1, 5-benzodioxepines in good yields.
- Damez,Labrosse,Lhoste,Sinou
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p. 1456 - 1458
(2007/10/03)
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- The Generalized Elimination Rule in Organic Chemistry I. Arguments in Support of Formation and Deprotonation of Solvent-Separated Ion Pairs in Solvolytic Dehydrobromination of Some Vicinal Dibromides
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Regioselectivity of dehydrobromination of a series of vicinal dibromides by the action of systems AcOH-AcONa and AcOH-N(C2H5)3 is more reasonably explained by the elimination rule than the variable transition state theory: precisely those directions of elimination which by this theory are considered as the most probable are not realized, and by the generalized elimination rule - they are considered to be impossible, and vice versa. Arguments are given in favor of formation of two types of solvent-separated ion pairs on elimination.
- Gevorkyan,Arakelyan,Avakyan,Obosyan
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p. 289 - 294
(2007/10/03)
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- Preparation of 2-methylenepropane-1,3-diol dicarboxylates
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2-Methylenepropane-1,3-diol dicarboxylates are prepared by reacting pentaerythritol tetracarboxylates on solid catalysts at elevated temperatures.
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- Enzymatic preparation of optically active 2-acetoxymethylglycidol, a new chiral building block in natural product synthesis
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Asymmetric hydrolysis of geminally disubstituted achiral diacetate 2 with lipase PPL yielded optically active (R)-(-)-2-acetoxymethylglycidol 3 and its reduction gave compound 6, useful as the tert-alcohol chiral building block.
- Seu,Kho
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p. 7015 - 7016
(2007/10/02)
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