Check patentability & draft patents in minutes with Patsnap Eureka AI!

1,2,3,4-Tetrahydroquinoxaline-6-carboxylic acid methyl ester and its preparation method

A technology of tetrahydroquinoxaline and methyl carboxylate, applied in the direction of organic chemistry and the like, can solve the problems of expensive raw materials, low yield, high pressure and the like, and achieve the effects of simple preparation method, short synthetic route and mild reaction

Inactive Publication Date: 2020-05-05
ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY
View PDF2 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, if the synthesis of tetrahydroquinoxaline compounds is prepared by ring formation, the steps are longer, the yield is low, there are many by-products, and the raw materials are expensive, so it is difficult to prepare in batches, which greatly limits the development of tetrahydroquinoxaline compounds. Inexpensive preparation and applications require
In particular, there are few reports on the types and synthesis methods of carboxylic acid tetrahydroquinoxalines, and there are few reports on the synthesis methods of tetrahydroquinoxalines found in searches (Journal of the Chemical Society, 1963, p. 4763-4766), but the used The method is catalytic hydrogenation, which requires high pressure and is not easy to operate

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0018] The method for preparing methyl 1,2,3,4-tetrahydroquinoxaline-6-carboxylate of the present invention has the following steps:

[0019] (1) Suspend 3,4-diaminobenzoic acid (1) in anhydrous methanol, then add concentrated sulfuric acid, and heat the reaction solution in an oil bath at 80~90℃ for 10~12 hours. When the reaction is complete, reduce Remove the methanol by pressure evaporation, pour the residue into ice water, and filter with suction to obtain methyl 3,4-diaminobenzoate (2);

[0020] (2) Dissolve methyl 3,4-diaminobenzoate (2) in DMF, then add [1,4]dioxane-2,3-diol (a), and then heat to 80~90℃ to react 6-8 hours, then extract, wash with water and dry to obtain methyl quinoxaline-6-carboxylate (3);

[0021] (3) Re-dissolve quinoxaline-6-carboxylic acid methyl ester (3) in methanol, add sodium borohydride, and react at 80~90℃ for 1~2 hours. After the reaction is completed, the excess is evaporated under reduced pressure Methanol is extracted and dried to obtain methy...

Embodiment 1

[0028] The preparation method of methyl 1,2,3,4-tetrahydroquinoxaline-6-carboxylate in this example is as follows:

[0029] (1) Synthesis of methyl 3,4-diaminobenzoate (2)

[0030] Take a 100ml single-mouth flask, add 3.04g (0.02mol) of 3,4-diaminobenzoic acid (1), add 50mL of methanol, stir to dissolve, then add 19.6g (0.2mol) of concentrated sulfuric acid, and stir at 90℃ for 12 hour. After the reaction was completed, the methanol was distilled off under reduced pressure, the residue was poured into ice water, and filtered and dried with suction to obtain 3.26 g of methyl 3,4-diaminobenzoate (2), with a yield of 98.1%.

[0031] ESI-MS: m / z: [M+1]:167.

[0032] 1 H NMR (300 MHz, CDCl 3 ): δ 7.44 (d, 1H), 7.38 (d, 1H), 6.64 (d, 1H), 3.82 (s, 3H), 3.52 (s, 4H).

[0033] 13 C NMR (75 MHz, DMSO-d 6 ): δ 51.62, 114.86, 118.31, 121.03, 123.22, 133.08, 140.39, 167.33.

[0034] (2) Synthesis of quinoxaline-6-carboxylic acid methyl ester (3)

[0035] Take a 100ml single-mouth bottle, add 3.32g ...

Embodiment 2

[0043] The preparation method of methyl 1,2,3,4-tetrahydroquinoxaline-6-carboxylate in this example is as follows:

[0044] (1) Synthesis of methyl 3,4-diaminobenzoate (2)

[0045] Take a 100ml single-necked flask, add 3.04g (0.02mol) of 3,4-diaminobenzoic acid and 50mL of methanol, stir to dissolve, then add 9.8g (0.1mol) of concentrated sulfuric acid, and stir for 12 hours at 90°C. After the reaction was completed, the methanol was distilled off under reduced pressure, the residue was poured into ice water, and dried with suction to obtain 3.17 g of methyl 3,4-diaminobenzoate (2), with a yield of 95.4%.

[0046] (2) Synthesis of quinoxaline-6-carboxylic acid methyl ester (3)

[0047] Take a 100ml single-mouth bottle, add 3.32g (0.02mol) of methyl 3,4-diaminobenzoate (2), and add 30ml of N,N-dimethylformamide, stir to dissolve, and then add [1, 4] Dioxane-2,3-diol (a) 2.4g (0.02mol). Stir at 90°C for 8 hours. Then, 3.4 g of methyl quinoxaline-6-carboxylate (3) was obtained after e...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses methyl 1,2,3,4-tetrahydroquinoxaline-6-carboxylate and a preparation method thereof. The structure formula of methyl 1,2,3,4-tetrahydroquinoxaline-6-carboxylate is defined in the specification. The preparation method comprises the following steps: firstly, a cheap starting raw material 3,4-diaminobenzoic acid is suspended in anhydrous methanol, and then methyl 3,4-diaminobenzoate is obtained by catalytic esterification with concentrated sulfuric acid; secondly, quinoxaline-6-methyl carboxylate is synthesized by cyclic condensation of methyl 3,4-diaminobenzoate with [1,4] dioxane-2,3-diol; and finally, quinoxaline-6-methyl carboxylate is reduced by a common reductant sodium borohydride to obtain methyl 1,2,3,4-tetrahydroquinoxaline-6-carboxylate. The preparation route and method have the advantages of cheap reagents, mild reaction conditions, and easy purification treatment of intermediate steps and products. Provided is the new method for preparing methyl 1,2,3,4-tetrahydroquinoxaline-6-carboxylate.

Description

Technical field [0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a method for preparing 1,2,3,4-tetrahydroquinoxaline-6-carboxylic acid methyl ester. Background technique [0002] Tetrahydroquinoxaline compounds have very diverse pharmacological activities. If they have good anticancer and antitumor activities, many drug molecules and natural products contain tetrahydroquinoxaline structures or fragments, so tetrahydroquinoxaline Oxaline derivatives are important pharmaceutical intermediates. However, if the synthesis of tetrahydroquinoxaline compounds is prepared by ring formation, the steps are longer, the yield is low, the by-products are many, and the raw materials are expensive, which is not easy to prepare in batches, which greatly limits the production of tetrahydroquinoxaline compounds. Cheap preparation and application needs. In particular, there are very few reports on the types and synthesis methods of carboxylic a...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C07D241/42
CPCC07D241/42
Inventor 靳清贤李争光胡路平唐佳利白向阳甄摇摇
Owner ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY
Features
  • R&D
  • Intellectual Property
  • Life Sciences
  • Materials
  • Tech Scout
Why Patsnap Eureka
  • Unparalleled Data Quality
  • Higher Quality Content
  • 60% Fewer Hallucinations
Social media
Patsnap Eureka Blog
Learn More

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2025 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com