- C-Bridged Bispyrrolidines and Bispiperidines as New Ligands
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The preparation of methylene-bridged C2-symmetric nitrogen-heterocycles as a new class of ligands is described, including methylene-bridged pyridines, quinolones, piperidines and pyrrolidines. These methylene-bridged aromatic systems are obtained via a microwave assisted Ziegler-type reaction. The separation of diastereomers and the application of the copper complexes of these ligands for cyclopropanation reactions proves the applicability of these new types of ligands.
- Stumpf, Tim-Daniel J.,Steinbach, Manfred,H?ltke, Magdalene,Heuger, Gerold,Grasemann, Franka,Fr?hlich, Roland,Schindler, Siegfried,G?ttlich, Richard
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p. 5538 - 5547
(2018/10/25)
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- Preparation method of 3,3-dialkoxylpropionate
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The invention belongs to the technical field of preparation of drug intermediates and in particular relates to a preparation method of 3,3-dialkoxylpropionate. The preparation method comprises the following steps: firstly, taking alkyl vinyl ether and trichloroacetyl chloride as raw materials; reacting under a certain condition to obtain an intermediate product 1,1,1-trichloro-4-alkoxyl-3-butene-2-one; reacting under an alkaline condition to obtain a target product 3,3-dialkoxylpropionate. The preparation method of the 3,3-dialkoxylpropionate, provided by the invention, has the following active effects that one raw material is directly used as a solvent (trichloroacetyl chloride) to react and the recycling and consumption of the solvent in a production process are reduced to a certain extent; after the reaction, an alcohol solvent can be recycled and is used for reacting for the next time, so that the recycling is realized and the scheme meets the requirements of green chemistry; a preparation process is simple, low in energy consumption and low in cost and can be in mass production.
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Paragraph 0023; 0024
(2017/09/02)
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- Superacidic Cyclization of Activated Anthranilonitriles into 2-Unsubstituted-4-aminoquinolines
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4-Aminoquinolines were prepared in a three-step synthesis starting from substituted anthranilonitriles. The condensation on 1,1,1-trichloro-4-ethoxybut-3-enone proceeded efficiently either neat or in refluxing EtOH. Cyclization in superacidic trifluoromethanesulfonic acid provided unstable intermediate, which upon treatment with NaOEt in ethanol, afforded the expected esters. Theoretical investigations pointed out a monoprotonated nitrilium as the reactive species during the cyclization process.
- Lavrard, Hubert,Larini, Paolo,Popowycz, Florence
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supporting information
p. 4203 - 4206
(2017/08/23)
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- Method for preparing 2-formyl-3-ethyl oxopropionate
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The invention relates to a method for preparing 2-formyl-3-ethyl oxopropionate. The method comprises the steps of subsequently adding ethanol, potassium carbonate, ethyl formate and NaH into vinyl ethyl ether and trichloro-acetyl chloride, which serve as starting raw materials, and carrying out multistep reactions, thereby obtaining 2-formyl-3-ethyl oxopropionate. The obtained final product has the purity of 99.7% and the yield of 45%. The method is readily available in raw materials, mild in reaction conditions and low in cost and is applicable to large-scale production in factories.
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Paragraph 0007; 0020
(2017/09/01)
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- A method for synthesizing allah Geleg sandbank (by machine translation)
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The invention relates to a method for preparing anti-II type diabetes drug allah Geleg sandbank method for the synthesis of bulk drug (Anagliptin). The lack of commercial synthetic allah Geleg sandbank solve the technical problems of the method. Synthetic method comprises the following steps : (1) with vinyl ether and trichloro acetyl chloride as the raw material, passes through the three-step reaction to obtain the aldehyde protected intermediates 4 ; The 3-amino-5-methyl pyrazole condensation for dehydrating and gets pyrazolo pyrimidine mother nucleus; Carboxy b ester hydrolysis to obtain 2-methyl-pyrazolo [1,5-a] pyrimidin 6-carboxylic acid 6 ; (2) to L-proline as a raw material, passes through the methyl esterification, ammoniation, acetylation, Carbonitride reaction to obtain the chiral cyano pyrrolizinone intermediate 11 ; Chiral cyano pyrrolizinone intermediate 11 And diamine fragment 12 In alkaline conditions to obtain intermediate affinity substituted 13 ; Finally, intermediate 13 Under the conditions of the hydrochloric acid removal protection Boc base namely obtain cyanopentanoyl Azolylamine intermediate 14 ; (3) 2-methyl-pyrazolo [1,5-a] pyrimidine-6-carboxylic acid 6 The cyano Azolylamine intermediate 14 The condensation conditions to obtain the bulk drug allah Geleg sandbank coupled. (by machine translation)
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Paragraph 0010
(2016/10/10)
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- Concise and high-yield synthesis of T808 and T808P for radiosynthesis of [18F]-T808, a PET tau tracer for Alzheimer's disease
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The authentic standard T808 and its corresponding mesylate precursor T808P were synthesized in six steps using ethyl vinyl ether and trichlorocetyl chloride as starting materials. The overall chemical yields of T808 and T808P were 35% and 52%, respectively. [18F]-T808 was synthesized from T808P by the nucleophilic substitution with K[18F]F/Kryptofix 2.2.2 and isolated by HPLC combined with solid-phase extraction (SPE) purification in 35-45% radiochemical yield with 37-370 GBq/μmol specific activity at end of bombardment (EOB).
- Gao, Mingzhang,Wang, Min,Zheng, Qi-Huang
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p. 254 - 257
(2014/01/17)
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- Regioselective synthesis of rare 3-halomethylphenols based on formal [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes
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The cyclization of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with halo-substituted enones afforded 3-difluorochloromethyl-, 3-difluorobromomethyl- , 3-dichloromethyl-, and 3-trichloromethylphenols with very good regioselectivity. The hydrolysis of the dichloromethyl group gave functionalized 3-formylphenols, which are not readily available by other methods. Thieme Stuttgart.
- Lubbe, Mathias,Mamat, Constantin,Langer, Peter
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body text
p. 1684 - 1686
(2009/05/30)
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- The Tandem Knoevenagel Hetero Diels-Alder Reaction with a Formylacetic Acid Equivalent. Synthesis of Dihydropyrancarboxylates
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The tandem Knoevenagel hetero Diels-Alder reaction of 4,4,4-trichloro-3-oxobutanal (9) with the aldehydes 10 as well as 16-21 and the enol ethers 6 as well as 28-32 followed by base-catalyzed methanolysis yields the methyl dihydro-2H-pyran-5-carboxylates 15, 22-27, and 33-37.In this reaction 9 is used as an equivalent of the non-stable formylacetic acid, since the trichloromethylcarbonyl moiety can be transformed into an alkoxycarbonyl group by solvolysis with an alcohol.As an example, in a three-component reaction 9 was condensed with propanal (10) in the presence of potassium fluoride to give the activated oxadiene 11 as an intermediate.This reacts with an ethyl vinyl ether (6), which is present as one component in the reaction mixture, to afford the cycloadduct 13 after acidic workup.Methanolysis of 13 in the presence of DBU yields the methyl dihydro-2H-pyran-5-carboxylate 15 in 50percent overall yield.Keywords: Dihydropyrancarboxylates/ Formylacetate/ Haloform clevage/ Hetero Diels-Alder reactions/ Knoevenagel reaction
- Tietze, Lutz F.,Meier, Heinrich,Nutt, Heinrich
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p. 643 - 650
(2007/10/02)
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- Enol Ethers, VIII. Acylation of Enol Ethers with Reactive Carbonyl Chlorides
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Enol ethers 2 are acylated under mild conditions with activated acyl chlorides, e. g. chloroacetyl chlorides 1a, b, cyanoacetyl chloride (6c), and malonic acid chlorides 6a, b in good yields.The products formed and the yield depend on the acylation potential of the acyl chlorides.The potential β-keto aldehydes 4, 5, and 1,3,5-tricarbonyl compounds 8 obtained are valuable intermediates for heterocyclic synthesis.
- Effenberger, Franz,Maier, Roland,Schoenwaelder, Karl-Heinz,Ziegler, Thomas
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p. 2766 - 2782
(2007/10/02)
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