2868-37-3Relevant academic research and scientific papers
Hydrolysis of Trimethyl Orthocyclopropanecarboxylate: A Change in Rate-Determining Step
Burt, R. A.,Chiang, Y.,Kresge, A. J.,McKinney, M. A.
, p. 3685 - 3687 (1982)
The rate constant for the hydronium ion catalyzed hydrolyis of trimethyl orthocyclopropanecarboxylate measured in dilute aqueous HCl, kH+=5300 M-1s-1, was found to be different from that measured in buffer solutions at pH 6-8, kH+=81 00 M-1s-1.This difference is similar to that observed for cyclic ortho esters and is taken as evicence for a change in the reaction mechanism from rate-determining conversion of ortho ester to a dialkoxycarbonium ion intermediate at high pH to rate-determining decomposition of the hydrogen ortho ester formed by hydration of this ion at low pH.Discovery of this mechanistic change in this acyclic system suggests that this is a general phenomenon common to all ortho esters substituted with carbication-stabilizing groups at their pro-acyl carbon atoms.
Direct quantitation of fatty acids present in bacteria and fungi: Stability of the cyclopropane ring to chlorotrimethylsilane
Eras, Jordi,Oro, Robert,Torres, Merce,Canela, Ramon
, p. 4923 - 4927 (2008)
The stability of the cyclopropane ring and the fatty acid composition of microbial cells were determined using chlorotrimethylsilane as reagent with three different conditions 80°C for 1 h, 60°C for 1 h, and 60°C for 2 h. Chlorotrimethylsilane permits a simultaneous extraction and derivatization of fatty acids. A basic method was used as reference. The bacteria, Escherichia coli, Burkholderia cepacia, and Lactobacillus brevis, and fungi Aspergillus niger and Gibberella fujikuroi were used. The stability of the cyclopropane ring on acidic conditions was tested using the cyclopropanecarboxylic acid and a commercial mixture of bacteria fatty acid methyl esters (BAME). Fisher's least significant difference test showed significant differences among the methods. The method using chlorotrimethylsilane and 1-pentanol for 1 h at 80°C gave the best results in cyclopropane, hydroxyl, and total fatty acid recoveries. This procedure allows the fast and easy one-step direct extraction derivatization.
Method for preparing cyclopropylamine intermediate cyclopropanecarboxylate from methyl ether
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Paragraph 0020-0060, (2021/07/31)
The invention discloses a method for preparing cyclopropylamine intermediate cyclopropanecarboxylate from methyl ether, and belongs to the technical field of synthesis of medical intermediates, wherein the method comprises the steps: by taking butyrolactone, dimethyl ether and concentrated sulfuric acid as initial raw materials, carrying out ring-opening reaction on butyrolactone under the action of dimethyl ether to generate methyl 4-methoxybutyrate; and carrying out cyclization reaction on the generated methyl 4-methoxybutyrate under the catalytic action of sodium methoxide to generate methyl cyclopropanecarboxylate and methanol. The method has the advantages that the production process is simple, the raw materials are cheap and easy to obtain, the atom utilization rate is high, the raw material and power cost is greatly reduced in the technological preparation process, and the reaction conditions are mild; and the reaction byproduct is methanol, treatment and recovery are convenient, the reaction yield can reach 75.54%-98.18%, and the production cost of the cyclopropylamine intermediate methyl cyclopropanecarboxylate is greatly reduced.
Preparation method of cyclopropylamine intermediate cyclopropanecarboxylic acid methyl ester
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Paragraph 0020-0048, (2021/05/15)
The invention relates to a preparation method of a cyclopropylamine intermediate methyl cyclopropanecarboxylate, and solves the technical problems that an existing preparation method is unreasonable, high in requirements on reaction equipment, complicated to operate, low in yield and unsuitable for industrial production. With methyl acetate and 1,2-dihaloethane as raw materials, and under the action of potassium carbonate and a phase transfer catalyst, alkylation reaction is carried out to obtain methyl cyclopropanecarboxylate. The method can be widely applied to the technical field of synthesis of medical intermediates.
mCPBA-mediated dioxygenation of unactivated alkenes for the synthesis of 5-imino-2-tetrahydrofuranyl methanol derivatives
Deng, Xiaojun,Zhang, Luwen,Liu, Huixia,Bai, Yu,He, Wei
supporting information, (2020/11/24)
A mCPBA-mediated, metal-free, intramolecular dioxygenation reaction of unactivated alkenes is reported. In the presence of m-chlorobenzoic peracid, different unsaturated amide substrates could be cyclized via epoxide intermediates, producing the corresponding 5-imino-2-tetrahydrofuranyl methanol products in up to 94% yield at room temperature.
Preparation method of methyl cyclopropanecarboxylate
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Paragraph 0022-0060, (2020/08/22)
The invention relates to a preparation method of methyl cyclopropanecarboxylate. The technical problems that an existing preparation method is unreasonable, by-products are unsalable, the requirementfor air tightness of a production device is high, and the existing preparation method is not suitable for industrial production are solved. According to the method, gamma-butyrolactone is used as a starting raw material, dimethyl sulfate and gamma-butyrolactone are subjected to transesterification ring opening under the action of a catalyst potassium carbonate, and cyclization is performed under the strong alkaline condition to generate methyl cyclopropanecarboxylate. The method can be widely applied to the technical field of medical intermediate synthesis.
Method for preparing cyclopropylamine midbody cyclopropanecarboxylic acid methyl ester
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Paragraph 0005; 0019-0032, (2018/03/26)
The invention discloses a method for preparing cyclopropylamine midbody cyclopropanecarboxylic acid methyl ester. First in a sealed reaction kettle, methanol is added dropwise into calcium carbide, togenerate calcium methoxide and acetylene; gamma-chloro methyl butyrate is added into calcium methoxide at 60-120 DEG C, the temperature is controlled to be constant in the reaction process, methanolgenerated in the process is collected, and the cyclopropanecarboxylic acid methyl ester is obtained through distillation. The method is simple in process, types of raw materials necessary for production are fewer, some of the raw materials can be reused, the yield is high, the quality is good, and the method is safe and environmentally friendly.
Practical synthesis of a heterocyclic immunosuppressive vitamin D analogue
Westermann, Juergen,Schneider, Matthias,Platzek, Johannes,Petrov, Orlin
, p. 200 - 205 (2012/12/26)
1α,25-Dlhydroxyvitamin D3 (calcitrioi) 1 and synthetic analogues thereof are highly potent compounds with a wide range of pharmacological activity making them of great interest for the pharmaceutical industry. Herein we report an improved synthesis of the calcitriol analogue 2, which features a novel oxazole-containing side chain. The crucial part of the synthesis was the development of a practical route to the β-keto phosphonate 28, allowing an easy introduction of the unnatural side chain by a Wittig Horner reaction.
Carbocation-forming reactions in ionic liquids
Creary, Xavier,Willis, Elizabeth D.,Gagnon, Madeleine
, p. 18114 - 18120 (2007/10/03)
A number of trifluoroacetates, mesylates, and triflates have been studied in ionic liquids. Several lines of evidence indicate that all of these substrates react via ionization to give carbocationic intermediates. For example, cumyl trifluoroacetates give mainly the elimination products, but the Hammett ρ+ value of -3.74 is consistent with a carbocationic process. The analogous exo-2-phenyl-endo-3-deutero-endo-bicyclo-[2.2.1]hept-2-yl trifluoroacetate gives an elimination where loss of the exo-hydrogen occurs from a cationic intermediate. 1-Adamantyl mesylate and 2-adamantyl triflate react to give simple substitution products derived from capture of 1- and 2-adamantyl carbocations by the residual water in the ionic liquid. The triflate derivative of pivaloin, trans-2-phenylcyclopropylcarbinyl mesylate, 2,2-dimethoxycyclobutyl triflate, the mesylate derivative of diethyl (phenylhydroxymethyl)-thiophosphonate, and Z-1-phenyl-5-trimethylsilyl-3-penten- 1-yl trifluoroacetate all give products derived carbocation rearrangements (kΔ processes), anti-7-Norbornenyl mesylate gives products with complete retention of configuration, indicative of involvement of the delocalized 7-norbornenyl cation. 1,6-Methano[10]annulen-11-yl triflate reacts in [BMIM][NTf2] to give 1,6-methano[10]annulen-11-ol, along with naphthalene, an oxidized product derived from loss of trifluoromethanesulfinate ion. Analogous loss of CF3SO2- can be seen in reaction of PhCH(CF3)OTf. Ionic liquids are therefore viable solvents for formation of carbocationic intermediates via kc and k Δ processes.
Processes for the preparation of cyclopropanecarboxylic acid and derivatives thereof
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, (2008/06/13)
Disclosed is a process for the preparation of cyclopropanecarboxylic acid by the non-catalytic, oxidation of cyclopropanecarboxaldehyde using molecular oxygen as the oxidant. Also disclosed are processes for the preparation of amides, esters and acid chlorides from cyclopropanecarboxylic acid.
