- The cobalt way to vitamin B6. Regioselective construction of the tetrasubstituted pyridine nucleus by cobalt-catalyzed alkyne-nitrile cooligomerizations
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Cocyclization of bis(trimethylsilyl)- and bis(trimethylstannyl)di-2-propynyl ether with acetonitrile provides a synthetic entry into 1,3-dihydro-6-methyl-4,7-bis(trimethylsilyl)- and bis(trimethylstannyl)-furo[3,4-c]pyridines. Regioselective electrophilic substitution of the respective silyl or stannyl groups allows for a regiocontrolled construction of tetrasubstituted pyridines. This method has been applied to a total synthesis of vitamin B6.
- Parnell, Carol A.,Peter,Vollhardt
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Read Online
- Method for environmentally friendly preparation of vitamin B6 and recycling of tail gas
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The invention relates to a method for environmentally friendly preparation of vitamin B6 and recycling of tail gas. The method comprises the following steps: carrying out a catalytic formylating reaction on carbon monoxide, hydrogen and 2-cyano-2-cis-butene-1,4-diol which is used as a starting material to prepare a 2-hydroxymethyl-3-cyano-4-hydroxy-n-butyraldehyde intermediate, condensing the intermediate with 2-aminopropionate or 2-aminopropionate hydrochloride, and carrying out salt formation to prepare the vitamin B6. The method does not use a 4-methyl-5-alkoxyoxazole intermediate that is expensive and generates a large amount of wastewater in the production process, and allows the tail gas to be recycled in synthesis of the starting raw material, so the method has the advantages of environmentally friendly process, high reaction selectivity, high product purity, high atom economy, and suitableness for the green industrial production of the vitamin B6.
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Paragraph 0042-0048; 0052-0055
(2019/07/04)
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- Method for preparing vitamin B6 by reducing 2-methyl-3-hydroxypyridine-4,5-diformic ether
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The invention discloses a method for preparing vitamin B6 by reducing 2-methyl-3-hydroxypyridine-4,5-diformic ether. 2-methyl-3-hydroxypyridine-4,5-diformic ether is dissolved into a solvent, sodium borohydride or potassium borohydride, lewis acid and tertiary amine are then sequentially added, and heating reaction is then carried out for 2 to 4 hours; after the reaction is completed, system temperature is lowered to be less than or equal to 10 DEG C, 10 percent ammonium chloride is then added, pH is regulated to be neutral, filtration enrichment and extraction are carried out, HCl gas is injected, and after concentration, standing is performed for crystallization, filtration and drying to obtain a crude product of vitamin B6. In the technical solution, under the joint action of sodium borohydride or potassium borohydride, lewis acid and tertiary amine, 2-methyl-3-hydroxypyridine-4,5-diformic ether is reduced to prepare vitamin B6. In the whole operation process, the adopted solvent does not need to undergo anhydrous treatment, high-pressure equipment does not need to be adopted as well, and the operation process is carried out under mild conditions.
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Paragraph 0029-0034
(2018/10/26)
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- A process for preparing vitamin B by the malic acid6 The method of
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The present invention relates to a method of using malic acid to prepare vitamin B6. The method comprises: using malic acid as a starting material; carrying out a hydroxymethylation reaction on the malic acid and formaldehyde in the presence of a basic catalyst to generate 2-hydroxy-2,3-dimethylol butanedioic acid; performing acid catalysis and lactonization for ring-forming to obtain 1H,4H-dihydrofuro[3,4-c]dihydrofuran-1,4-diketone (III); under base catalysis, condensing the obtained compound III and nitro ethane to obtain a compound IV; reducing the compound IV by using sodium borohydride or potassium borohydride to obtain a compound V; performing catalytic hydrogenation on the compound V to obtain a compound VI; and performing hydrolysis and ring-forming on the compound VI in an ethanol-hydrochloric acid system to obtain vitamin B6. According to the method of the present invention, the use of the 4-methyl-5-alkoxyl oxazole intermediate that is expensive and of which the preparation process causes pollution is avoid; the raw materials are inexpensive and readily available; the process is short; and the cost is low. The method in the present invention is simple in operation, less in wastewater discharge, highly environmentally friendly, and suitable for green industrial production of VB6.
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- Vitamin B6 synthesis method (by machine translation)
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The present invention provides a vitamin B6 preparation method, in particular, the method of the invention in an inert solvent, the 4 - methyl - 5 - ethoxy - 2 - carboxyl oxazole and 2 - n-propyl - 4, 7 - dihydro - 1, 3 - British two wicked age to one-step reaction, thereby obtaining a preparation of vitamin B6 in the middle of the key type III compound. The method of the invention has small pollution, short reaction route and the like. (by machine translation)
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Paragraph 0082-0083
(2017/09/12)
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- Vitamin B6 for the continuous preparation of
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The invention discloses a continuous preparation method of vitamin B6; in a continuous reaction device with multiple series-connection kettles, 4-methyl-5-ethoxy oxazole and 2-isopropyl-4,7-dihydro-1,3-dioxepin are subjected to a Diels-Alder addition reaction, a key intermediate compound represented by the formula IV is obtained, and the key intermediate compound represented by the formula IV is further subjected to aromatization and acidolysis to obtain the vitamin B6. According to the method, the damage degree of the reactants and the product is reduced, the occurrence of side reactions can be reduced, the reaction selectivity and the product yield and production efficiency are improved, and the high-purity vitamin B6 can be obtained.
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Paragraph 0061; 0081; 0083
(2018/01/13)
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- Vitamin B6 Intermediate 4 - methyl - 5 - alkyl silicon oxygen radical wicked zuo, its preparation method and process for producing vitamin B6 The method of
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The invention relates to a vitamin B6 intermediate 4-methyl-5-alkylsiloxane oxazole, a preparation method thereof as well as a method for preparing the vitamin B6. 4-methyl-5-alkylsiloxane oxazole has the structure shown as the formula I. 2-alanine and formaldehyde or paraformaldehyde are subjected to N-hydroxymethylation and lactonization in a solvent under the action of an acid catalyst to obtain 4-methyl-tetrahydro-oxazole-5-ketone (II), the ketone is not separated and is directly subjected to chloro substitution, silicon etherification and an elimination reaction in the presence of an acid-binding agent to generate 4-methyl-5-alkylsiloxane oxazole (I). 4-methyl-5-alkylsiloxane oxazole and 2-n-propyl-1,3-dioxo-5-cycloheptene are subjected to addition and hydrolysis to prepare the vitamin B6. The process is short, the operation is easy, little wastewater is produced, safety and environmental protection are realized, the reaction selectivity is good, a product is low in cost and high in purity, and industrial production is facilitated better.
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Paragraph 0068; 0069
(2017/08/25)
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- Method for preparing vitamin B6 from 2-methyl-2-cyclopentenone
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The invention relates to a method for preparing vitamin B6 from 2-methyl-2-cyclopentenone. The method comprises the steps that 2-methyl-2-cyclopentenone is taken as a starting raw material and reacts with formaldehyde through a hydroxymethylation reaction under catalysis of a basic catalyst to generate 4,5-dihydroxyl-2-methyl-2-cyclopentenone; separation is not conducted, 4,5-dihydroxyl-2-methyl-2-cyclopentenone is ozonized to obtain 2-3-dihydroxyl-4,5-dioxo-n-hexaldehyde, and obtained 2-3-dihydroxyl-4,5-dioxo-n-hexaldehyde and ammonia are directly subjected to condensation and hydrochloric acid acidizing to prepare the vitamin B6. The method is short in technological process, high in atom utilization rate of the adopted raw materials, low in product cost, little in wastewater discharge, good in environmental friendliness and suitable for industrialized production of the VB6.
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Paragraph 0042; 0043
(2017/01/02)
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- Improved oxazole Method for the Practical and Efficient Preparation of Pyridoxine Hydrochloride (Vitamin B6)
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Vitamin B6, a well-studied vitamin B, has been synthesized using an oxazole method for the past 20 years. The oxazole method provided 56.2% overall yield but also generated safety, environmental, and health problems, such as using toxic benzene as solvent and unstable, corrosive, and pollutive HCl and POCl3 as reagents. To use the same equipment but the least amount of toxic agents, we developed new reaction conditions for the early steps. For example, we successfully replaced toxic HCl/benzene conditions with NaHSO4/PhCH3 conditions and also developed a novel and efficient dehydrating agent trichloroisocyanuric acid/Ph3P/Et 3N to synthesize the key intermediate 5-butoxy-4-methyl oxazole, instead of using phosphorus oxychloride. These improvements resolved safety, waste avoidance, and workup issues that plagued the previous methodologies. Our process comprised six easy synthetic steps and generated vitamin B6 with 99.4% purity in 56.4% overall yield.
- Zou, Ye,Shi, Xiangjun,Zhang, Genbao,Li, Zhenhua,Jin, Can,Su, Weike
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p. 1498 - 1502
(2014/01/06)
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- MANUFACTURE OF VITAMIN B6
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The present invention relates to a process for the manufacture of pyridoxamine, pyridoxine and further clodely related 3-hydroxy-pyridine derivatives and of acid salts thereof. Pyridoxamine and pyridoxine belong to the vitamin B6 group. This new multistep process is represented schematically in the following Reaction Scheme (formula (I)).
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Page/Page column 16
(2008/06/13)
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- 1,3 DIHYDROFURO [3,4-c]PYRIDINES AND THEIR PREPARATION
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The present invention relates to novel 1,3-dihydrofuro[3,4-c]pyridines which are useful intermediates in the synthesis of pyridoxines and a method for their preparation by cobalt(I) complex-catalysed [2 + 2 + 2]-cycloaddition of di-[(3-dimethyl-C1-4-alkoxysilyl)-2-propynyl)] ethers with acetonitrile.
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Page/Page column 8
(2010/02/14)
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- METHOD FOR PRODUCING PYRIDOXINE OR AN ACID ADDITION SALT THEREOF
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The invention relates to a method for producing pyridoxine and the acid addition salts thereof, said method comprising the following steps: i. the Diels-Alder adduct (I) of 4-methyloxazole and a 4,7-dihydro-1,3-dioxepin is dissolved in a mixture of an organic solvent which can be at least partially mixed with water, and water, and the solution of (I) thus obtained is treated at an elevated temperature, optionally in the presence of a catalytically active quantity of an acid, until at least part of the compound (I) is converted into the corresponding 1,5-dihydro-8-methyl-[1,3]dioxepin-[5,6c]pyridin-9-ol (II); ii. the compound (II) of the solution obtained in step i., or the acid addition salt of said compound, is precipitated by adding a precipitant, and the compound (II) or the acid addition salt thereof is isolated; and iii. the compound (II) obtained in step i., or the acid addition salt thereof, is converted into pyridoxine or an acid addition salt thereof.
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Page/Page column 16-18
(2008/06/13)
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- Compositions for the treatment of migraine, containing potassium, magnesium and pyridoxine
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PCT No. PCT/GB97/00213 Sec. 371 Date Jan. 21, 1998 Sec. 102(e) Date Jan. 21, 1998 PCT Filed Jan. 24, 1997 PCT Pub. No. WO97/26897 PCT Pub. Date Jul. 31, 1997Compositions for the treatment and prevention of migraine or stress headaches wherein there is supplied a combination of potassium, magnesium and pyridoxine optionally in association with other nutrients and/or simple analgesics.
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- Packing for chromatography and method for separating water soluble organic compounds using the same
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A packing for use in chromatography which comprises a cyclic amino-substituted silane compound having the formula (I): STR1 wherein R1, R2 and R3 are the same or different and are each an alkyl having 1 to 5 carbon atoms, an alkoxy having 1 to 3 carbon atoms, hydroxy or a halogen atom in which at least one of R1, R2 and R3 are an alkoxy group or a halogen atom; R4 is ω-piperidino, ω-piperazino or ω-morpholino group which is optionally substituted by a straight chain or branched chain lower alkyl group; n is an integer of from 2 to 10, said compound being grafted onto an inorganic carrier having hydroxyl group on its surface, and a method for separating water soluble organic compounds by chromatography using said packing.
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- Controlled release pharmaceutical preparation
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A controlled release pharmaceutical preparation comprising a core containing a medicinal compound and a coating layer containing a water-repellent salt and a water-insoluble and slightly water-permeable acrylic polymer having trimethylammoniumethyl group. Said preparation releases a medicinal compound in a sigmoid type dissolution pattern irrespective of the PH of a dissolution medium.
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- A Convenient Synthesis of Pyridoxine
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A novel and convenient synthesis of pyridoxine starting from N-(1-cyanoethyl)formamide is described.The reaction of N-(cyanoethyl)acylamides with olefins in the presence of an acid catalyst gave 3-amino-2-methylpyridines.Similar reaction of N-(1-cyanoethyl)formamide with fumaronitrile in the presence of trifluoroacetic acid afforded 5-amino-6-methylpyridine-3,4-dicarbonitrile, which was easily converted to pyridoxine by reduction and diazotization.Keywords - N-(1-cyanoethyl)acylamide; fumaronitrile; 3-amino-2-methylpyridine; 3-cyano-2-propen-1-yl acetate; pyridoxine
- Shimada, Sadakatsu,Oki, Masaharu
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- Production of pyridoxine
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Pyridoxine or its acid addition salt is produced by reacting 4-carboxymethyl-5-substituted oxy-oxazoles with 4,7-dihydro-1,3-dioxepines in the presence of a compound of the formula STR1 wherein X is oxygen, --NH--, or --NH--NH-- and, then, subjecting the resultant compound to hydrolysis. This process offers industrially more advantageous production of pyridoxine than hitherto known processes.
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- ONE STEP SYNTHESIS OF α-AMINOALKYLFURANS AND ITS APPLICATION TO A FACILE SYNTHESIS OF PYRIDOXINE (VITAMIN B6)
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One step synthesis of α-aminoalkylfurans was achieved by the reaction of α-methoxyurethanes or α-methoxyamides with furan.This method was applied to an efficient synthesis of pyridoxine.
- Shono, Tatsuya,Matsumura, Yoshihiro,Tsubata, Kenji,Takata, Jiro
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p. 1121 - 1124
(2007/10/02)
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- Manufacture of pyridoxin
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An industrially advantageous process for the manufacture of vitamin B6 (pyridoxin) from 2-methyl-3-hydroxy-4,5-bis-(halomethyl)-pyridine, wherein the starting compound is first converted in the conventional manner to the corresponding pure acetoxy compound which is reacted with an alkali metal acetate, alkaline earth metal acetate or tertiary ammonium acetate to give pyridoxin triacetate, from which pyridoxin can be liberated by hydrolysis or trans-esterification.
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