- Last of the gem-Difluorocycloalkanes: Synthesis and Characterization of 2,2-Difluorocyclobutyl-Substituted Building Blocks
-
An efficient approach to synthesis of previously unavailable 2-substituted difluorocyclobutane building blocks was developed and applied on a multigram scale. The key step of the synthetic sequence included deoxofluorination of O-protected 2-(hydroxylmeth
- Chernykh, Anton V.,Melnykov, Kostiantyn P.,Tolmacheva, Nataliya A.,Kondratov, Ivan S.,Radchenko, Dmytro S.,Daniliuc, Constantin G.,Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.,Kuchkovska, Yuliya O.,Grygorenko, Oleksandr O.
-
p. 8487 - 8496
(2019/08/30)
-
- Preparation method of 2-fluorous methyl acrylate
-
The invention discloses a preparation method of 2-fluorous methyl acrylate. The preparation method comprises the following steps: (1) pyrolyzing trimethyl orthoacetate at 150 to 300 DEG C to obtain 1,1-dimethoxy ethane; (2) enabling reaction between 1,1-dimethoxy ethane and dichlorofluoromethane to obtain 1-chloride-1-fluorine-2,2-dimethoxy cyclopropane; (3) pyrolyzing the 1-chloride-1-fluorine-2,2-dimethoxy cyclopropane to obtain 2-fluorous methyl acrylate shown as the formula I.
- -
-
Paragraph 0050; 0051; 0052; 0053; 0054; 0055; 0056; 0057
(2017/05/12)
-
- METHOD FOR PRODUCING HALOGENATED ACRYLIC ACID DERIVATIVE
-
To provide a novel method for producing a halogenated acrylic acid derivative. A compound represented by the formula (1): (wherein each of R1 and R2 which are independent of each other, is a hydrogen atom or a monovalent group essentially containing a carbon atom, or R1 and R2 together form a ring, R3 is a monovalent group capable of being desorbed by R3OH removal reaction, and each of R4 and R5 which are independent of each other, is a hydrogen atom or a monovalent group essentially containing a carbon atom) and having a boiling point of at most 500° C., is subjected to R3OH removal reaction in a vapor phase in the presence of a solid catalyst to obtain an ethene derivative represented by the formula (2): the ethene derivative represented by the formula (2) and a halogenated methane represented by the formula (3): [in-line-formulae]CHXYZ??(3)[/in-line-formulae] (wherein each of X, Y and Z which are independent of one another, is a halogen atom) are reacted in the presence of a basic compound and a phase transfer catalyst, to obtain a cyclopropane derivative represented by the formula (4): and the cyclopropane derivative represented by the formula (4) is reacted by heating in a liquid phase or in a vapor phase to obtain a halogenated acrylic acid ester derivative represented by the formula (5):
- -
-
Paragraph 0098-0101
(2017/03/21)
-
- Synthesis of mimosamycin
-
Mimosamycin (1) was synthesized in eight steps with an overall yield of 13% from 2-methoxy-3-methyl-1,4-benzoquinone by regioselective introduction of a chloromethyl group at C-6 and a methoxycarbonylmethyl group at C-5 and subsequent reaction of the intermediate methyl (o- (chloromethyl)phenyl)acetate derivative 16 with methylamine. Oxidation of the 5,7,8-trimethoxy-2,6-dimethyl-1,4-dihydroisoquinoline-3(2H)-one 17 thus obtained, using cerium(IV) ammonium nitrate as a selective oxidizing agent, gave mimosamycin (1) in good overall yield.
- Kesteleyn, Bart,De Kimpe, Norbert
-
p. 635 - 639
(2007/10/03)
-
- Solid-liquid phase transfer catalytic method for the preparation of acyclic and cyclic ketene acetals
-
Solid-liquid phase transfer catalytic elimination reaction for the preparation of acyclic and cyclic ketene acetals has been developed.
- Zheng, Qi-Huang,Su, Jing
-
p. 3467 - 3476
(2007/10/03)
-
- A short and simple synthesis of ketene acetals
-
A novel and convenient synthesis of ketene acetals 1a-g in moderate to good yield has been achieved starting from acetonitrile by using Pinner reaction approach.
- Argade,Joglekar
-
p. 1979 - 1984
(2007/10/02)
-
- A short and effective synthesis of dimethyl 2-methoxycarbonyl-3-methylenesuccinate
-
Cycloaddition of ketene dimethyl acetal (7) to dimethyl butynedioate (8) followed by electrocyclic ring opening yields diene 10. This can be hydrolyzed readily to the title compound 1.
- Dehmlow,Veretenov
-
p. 939 - 940
(2007/10/02)
-
- Experimental and Theoretical Studies of the Gas-Phase Protonation of Vinyl Ethers, Vinyl Sulfides, and Vinyl Selenides
-
A series of nine chalcogen-substituted ethylenes (chalcogen = O, S, Se) have been synthesized, and their gas-phase proton affinities (PA) were determined experimentally by measuring gas-phase basicities (GB) in an ion cyclotron resonance (ICR) spectrometer and theoretically by means of ab initio MO calculations at the STO-3G and 3-21G* levels.A satisfactory correlation (r = 0.978, slope = 1.41) has been obtained between the experimental and calculated 3-21G(*) values.In contrast with a number of previous reports, we consistently found that third- (SMe) and fourth-row (SeMe) substituents do not stabilize better the adjecent positive charge than does the second-row substituent OMe, even in the gas phase.In fact, comparison of experimental proton affinity value of ethylene with that of mono(methylchalco)ethylenes indicates that OMe, SMe, and SeMe groups stabilize the corresponding ethyl cations to very much the same extent.In 2-propyl cations the trend is O > S > Se, but the differences (δΔ in Table III) are quite small: 1.2 kcal mol-1 between O and S and 1.4 kcal mol-1 between S and Se.The superior ability of oxygen in carbenium ion stabilization appears the most clearly in the protonation of bis(methylchalco)ethylenes: dimethoxyethyl cation is more stable than the corresponding thio species by ca. 5.5 kcal mol-1, whereas dithio- and diselenocarbenium ions again have very similar stabilities.These conclusions are supported and extended by ab initio results on optimized geometries.
- Oesapay, K.,Delhalle, J.,Nsunda, K. M.,Rolli, E.,Houriet, R.,Hevesi, L.
-
p. 5028 - 5036
(2007/10/02)
-
- Nitrene-like Behaviour of Diazoazoles?
-
Treatment of 4,5-dicyano-2-diazoimidazole, 2-diazoimidazole, amd 3-diazopyrazole with 1,1-dimethoxyethene affords azolo-as-triazines (1c), (3c), and (8c), respectively; the involvement as intermediates of either aziridines (d), arising from a 'nitrene-like reaction' of diazoazoles, or azoalkenes (b) should be questioned at present.
- Farras, Jaume,Vilarrasa, Jaume
-
p. 1127 - 1129
(2007/10/02)
-
- 13C NMR study of the structures of some acyclic and cyclic ketene acetals
-
A 13C NMR study of the spatial structures of some acyclic and cyclic ketene acetals (for example, ketene dimethyl acetal and 2-methylene-1,3-dioxolane) has been carried out. The conclusions obtained are based on observation of the effect of structural changes on the 13C NMR chemical shift of the β carbon on the ketene moity. Since the extent of p-π conjugation and hence the 13C chemical shift of this carbon depend on the spatial orientation of the alkoxy groups about the O-C(sp2) bonds, the shift concerned may be used as a measure of the planarity of the system. The most stable retamers of ketene dimethyl acetal are s-cis,s-cis (planar) and s-cis,gauche (slightly nonplanar), in the order of decreasing stability. For ketene dialkyl acetals, the relative stability of the planar s-cis,s-cis form decreases with increasing bulkiness of the alkyl groups, but at least for primary and secondary alkyl groups, the s-cis,s-cis rotamer appears to be the most favored species. The conformations of 5- to 8-membered cyclic ketene acetals are discussed and compared with those of the corresponding cyclic vinyl ethers and hydrocarbons.
- Taskinen,Pentikaeinen
-
p. 2365 - 2370
(2007/10/04)
-