20902-48-1

Upstream product

• 617-27-6 DL-alanine ethyl ester hydrochloride 
• 95-92-1 oxalic acid diethyl ester 
• 64-17-5 ethanol 
• 302-72-7 rac-Ala-OH 
• 4755-77-5 Ethyl oxalyl chloride 
• 56-41-7 L-alanin 
• 144-62-7 oxalic acid 
• 687-47-8 (S)-Ethyl lactate 

Downstream Products

• 23429-04-1 4-methyl-5-ethoxy-2-oxazole carboxylate ethyl ester 
• 5006-20-2 5-ethoxy-4-methyl-oxazole 

Relevant academic research and scientific papers

Preparation method of N-alkoxy oxalyl alanine ester

The invention discloses a preparation method of N-alkoxy oxalyl alanine ester, which comprises the following steps: (1) under the action of triphosgene and an organic alkali, carrying out an esterification reaction on alanine and an alcohol to obtain alanine ester hydrochloride; and (2) under the action of the organic alkali, carrying out an amidation reaction on the alanine ester hydrochloride obtained in the step (1) and oxalic ester, and after the reaction is finished, carrying out post-treatment to obtain the N-alkoxy oxalyl alanine ester. According to the preparation method, the triphosgene and the organic alkali are used as reaction additives, so that the use of toxic solvent benzene is avoided, the reaction time is shortened, the product purity and the reaction yield are high, and the preparation method is suitable for industrial production.

Improved oxazole Method for the Practical and Efficient Preparation of Pyridoxine Hydrochloride (Vitamin B6)

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.

PROCESS FOR THE MANUFACTURE OF N-ALKOXALYL-ALANINATES

A process for the manufacture of alkyl N-alkoxalyl-alaninates of the formula alkylO-CO-CO-NH-CH(CH3)-CO-Oalkyl comprises reacting alanine with a dialkyl oxalate under substantially non-acidic conditions, which may be created by carrying out the reaction in the presence of a base. The reaction may furthermore be carried out in the presence of added alkanol, preferably one featuring the alkyl group corresponding to that of the employed dialkyl oxalate. The monoesters N-alkoxalyl-alanine of the formula alkylO-CO-CO-NH-CH(CH3)-COOH, which as intermediates in the process can be isolated therefrom, are novel and as such are also an object of the present invention. The alkyl N-alkoxalyl-alaninates are useful intermediates in the multistep process for the manufacture of vitamin B6.

N-Boc ethyl oxamate: A new nitrogen nucleophile for use in Mitsunobu reactions

N-Boc ethyl oxamate can be directly coupled with primary and secondary alcohols under Mitsunobu conditions to afford various N-Boc mines after mild deprotection.

Synthesis of 4-hydroxy-6,9-difluorobenz[g]isoquinoline-5,10-diones and conversions to 4-hydroxy-6,9-bis[(aminoalkyl)amino]-benz[g]isoquinoline-5,10-diones

Synthetic procedures have been developed which lead to 4-hydroxy-6,9-difluorobenz[g]isoquinoline-5,10-dione (4a) and its 3-methyl analogue 4b. Attempts to displace the fluorides from 4a with N,N-dimethylethylenediamine were unsuccessful. Analogue 4a on treatment with N-(t-butoxycarbonyl)ethylene diamine led to 15, formed from addition of the nucleophilic amine to C-3. On the other hand, analogue 4b, on treatment with N,N-dimethylethylenediamine led to the anticipated difluoride displacement product 3c. The protection of the hydroxy group of 4a by benzylation with phenyldiazomethane led to 4c which on treatment with N-(t-butoxycarbonyl)ethylene diamine or N,N-dimethylethylenediamine led to the corresponding 6,9-bis-substituted analogues 18a and 18b, respectively. Reductive debenzylations of 18a and 18b by hydrogenation over Pearlman's catalyst also effected partial reductions of the quinone. However, air oxidation of the over reduced products led to 3a and 3b, respectively. Treatment of 3a with hydrogen chloride gas led to the hydrochloride salt of 3d. Addition of O-p-Methoxybenzyl-N,N'-diisopropylurea to 4a led to the p-methoxybenzyl analogue 4d. Treatment of 4d with N,N-dimethylethylene diamine or N-(t-butoxycarbonyl)ethylene diamine led to displacements of the fluorides to yield 18c and 18d, respectively. Deprotection of 18c to 3b was accomplished using methanesulfonic acid. Treatment of 18d with trifluoroacetic acid followed by addition of maleic acid led to dimaleate salt of 3d.