- Preparation method of 2-(trifluoromethyl) pyridine-3-formaldehyde (I)
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The invention discloses a preparation method of 2-(trifluoromethyl) pyridine-3-formaldehyde (I), and belongs to the technical field of preparation methods of chemical drug intermediates. Acrolein, ammonium hydroxide and 4,4,4-trifluoro-3-oxobutyraldehyde are used as raw materials, and the 2-(trifluoromethyl) pyridine-3-formaldehyde is prepared through aldimine condensation, cyclization and hydrolysis deprotection. The preparation method of the 2-(trifluoromethyl) pyridine-3-formaldehyde (I) has the advantages that the adopted raw materials are relatively cheap and easy to obtain, the method is simple and convenient to operate, the yield of the product is higher, and the industrialized value is higher.
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Paragraph 0022; 0023; 0024; 0025
(2019/05/04)
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- SYNTHESE D'IMINES LINEAIRES NON-STABILISEES PAR REACTIONS GAZ-SOLIDE SOUS VIDE(1).
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Unstabilized imines are synthetized in gram-scale by vacuum dehydrochlorination of N-chloroalkylamines and by vacuum dehydrocyanation of α-aminonitriles on solid base.All the new compounds are characterized at low temperature by 1H, 13C NMR and IR spectroscopy.
- Guillemin, Jean-Claude,Denis, Jean-Marc
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p. 4431 - 4446
(2007/10/02)
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- Gasphase Reactions, 61. - Cycloalkanimines 2H-Azirine, 1-Azetidine, 1-Pyrroline, 1-Piperideine, and 3,4,5,6-Tetrahydro-2H-azepine: Preparation and Photoelectron Spectra
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For preparation of the easily oligomerizing cycloalkanimines , the following gasphase reactions are optimized PE spectroscopically: for the three membered ring imine, 2H-azirine, the heterogeneous KOR dehydrochlorination of the 2-chloroethyl azide preceding the thermolysis of the resulting vinyl azide, and for the lager rings, 1-azetine (n=2), 1-pyrroline (n=3), 1-piperideine (n=4) as well as the seven-membered 3,4,5,6-tetrahydro-2H-azepine, the consecutive chlorination of the corresponding cycloalkylamine over solid N-chlorosuccinimide followed by KOR dehydrochlorination of the N-chloro derivative formed.The PE spectra of all cyclic alkanimines prepared are assigned based on geometry-optimized MNDO calculations, and their electronic structures are discussed by molecular state comparison with increasing ring size and with the isoelectronic series of the cycloalkenes.The thermal ring opening of 1-azetine to 2-azabutadiene is investigated by PE spectroscopic real-time gas analysis; its ionization pattern is assigned by comparison with other azabutadienes.
- Bock, Hans,Dammel, Ralph
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p. 1971 - 1986
(2007/10/02)
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- Reactions retrodieniques - XVIII. Synthese par thermolyse eclair et etude d'allenes fonctionnels reactifs
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The flash thermolysis of anthracenic Diels-Alder adducts leads to the obtention and low temperature spectroscopic characterization (ir, 1H and 13C nmr) of allenes 1-11 (see table 1).Butadienal 1, the simplest α-allenic aldehyde, is thus obtained from its precursors 13, 14 or 17.Thermolysis of the intermediate allylic alcohol 15 gives buta-1,3-dien-2-ol 18, which tautomerizes to methylvinylketone even at -100 deg C.An attempted synthesis of a natural δ-allenic ester, methyl laballenate 19, was undertaken using this method; however, the thermolysis of ester 24 leads via 19 to methyl acrylate and (Z + E) pentadeca-1,3-diene 25, resulting formally from a retroene cleavage of 19.Thermolyses of related esters 26 and 27 give in the same way the corresponding 1,3-dienes.Allenes with gem electron attracting groups are very reactive compounds acting as ketene equivalents in nucleophilic additions and or dipolar cycloadditions.The thermolysis of adducts 28-32, obtained by Knoevenagel condensation of malonic derivatives with ketone 16, leads to the following allenes of this series: 1,1-dicyano-1-methoxycarbonyl propadiene 4, 1,1-bis-(ethoxycarbonyl) propadiene 5 and 1,1-bis-(methoxycarbonyl) propadiene 6.Yields and purity are lower in the case of 3 and 5, owing to the presence of the thermolabile ethoxycarbonyl groups.The possibility of performing nucleophilic additions to the most polymerizable of these allenes: 1,1-dicyanopropadiene 2, is demonstrated by its clean, good yield additions at -50 deg C with methanol, methyl lithium, aniline ir dimethylamine.Allenes O or N-substituted on the allenic carbon are often reactive substances and are known mainly in the case of alkyl ethers and tertiary amines.The flash thermolysis of allylic alcohol 38 gives in good yield propanediol 7 which tautomerizes into acrolein at -50 deg C.Trimethylsilyloxypropadiene 8, 1-trimethylsilyloxybuta-1,2-diene 9 and 3-trimethylsilyloxybuta-1,2-diene 10 could also be obtained from their precursors 40, 44-46.Thermolysis of amine 49 leads in the same way to propadienamine 11, a reactive enamine postulated as a cosmic species and tautomerizing at -65 deg C into 1-azabuta-1,3-diene 50.
- Hakiki, Abdelhak,Ripoll, Jean-Louis,Thuillier, Andre
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p. 911 - 920
(2007/10/02)
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