Novel method for preparing cinnoline derivative midbody dichloro dimethyl benzoquinone

Abstract

The invention relates to a cinnoline derivative midbody, in particular to a novel method for preparing cinnoline derivative midbody dichloro dimethyl benzoquinone. 2, 3-xylenol is adopted as starting raw materials in the method, and target compounds are obtained through oxidization and chlorination.

Description

technical field

[0001] The invention relates to a novel preparation method of a cinnoline derivative intermediate, in particular to a novel preparation method of dichlorodimethylbenzoquinone. technical background

[0002] Dichlorodimethylbenzoquinone, chemical name 2,3-dichloro-5,6-dimethylcyclohexa-2,5-diene-1,4-dione, CAS: 15707-31-0, structural formula:

[0003]

[0004] Cinnoline derivatives are a class of compounds that play an important role in the pharmaceutical field, especially for bacterial and fungal fungicides. Dichlorodimethylbenzoquinone is an important intermediate in the synthesis of cinnoline derivatives. At present, the usual synthesis method is: add dimethylbenzoquinone to concentrated hydrochloric acid, heat and stir, then add concentrated nitric acid, continue heating and stirring for 2 hours, cool to room temperature, add ethyl acetate for extraction, collect the organic phase, dry, Concentrate to obtain a crude product, and then recrystallize to o...

Examples

Embodiment 1

[0020] (1) Preparation of dimethylbenzoquinone

[0021] Add 24.4g of 2,3-xylenol to 150ml of acetone, slowly add 60ml of 30% hydrogen peroxide dropwise, stir at room temperature for 24 hours, concentrate under reduced pressure to remove acetone, add ethyl acetate and water, carry out extraction and separation, collect the organic phase, and dry , concentrated, and the residue was recrystallized from ethyl acetate-petroleum ether (volume ratio 1:2) to obtain 22.6 g of compound 2 as a yellow solid (yield 83.08%).

[0022] (2) Preparation of Dichlorodimethylbenzoquinone

[0023] Dissolve 22g of dimethylbenzoquinone in 200ml of acetic acid, stir, heat to reflux, feed chlorine gas, react for 5 hours, stop the reaction, remove most of the acetic acid under reduced pressure, then add ethyl acetate and water for extraction and liquid separation, The organic phase was collected, dried, concentrated, and the residue was separated on a silica gel column to obtain 29 g of dichlorodimethy...

technical field

[0001] The invention relates to a novel preparation method of a cinnoline derivative intermediate, in particular to a novel preparation method of dichlorodimethylbenzoquinone. technical background

[0002] Dichlorodimethylbenzoquinone, chemical name 2,3-dichloro-5,6-dimethylcyclohexa-2,5-diene-1,4-dione, CAS: 15707-31-0, structural formula:

[0003]

[0004] Cinnoline derivatives are a class of compounds that play an important role in the pharmaceutical field, especially for bacterial and fungal fungicides. Dichlorodimethylbenzoquinone is an important intermediate in the synthesis of cinnoline derivatives. At present, the usual synthesis method is: add dimethylbenzoquinone to concentrated hydrochloric acid, heat and stir, then add concentrated nitric acid, continue heating and stirring for 2 hours, cool to room temperature, add ethyl acetate for extraction, collect the organic phase, dry, Concentrate to obtain a crude product, and then recrystallize to o...

Examples

Embodiment 1

[0020] (1) Preparation of dimethylbenzoquinone

[0021] Add 24.4g of 2,3-xylenol to 150ml of acetone, slowly add 60ml of 30% hydrogen peroxide dropwise, stir at room temperature for 24 hours, concentrate under reduced pressure to remove acetone, add ethyl acetate and water, carry out extraction and separation, collect the organic phase, and dry , concentrated, and the residue was recrystallized from ethyl acetate-petroleum ether (volume ratio 1:2) to obtain 22.6 g of compound 2 as a yellow solid (yield 83.08%).

[0022] (2) Preparation of Dichlorodimethylbenzoquinone

[0023] Dissolve 22g of dimethylbenzoquinone in 200ml of acetic acid, stir, heat to reflux, feed chlorine gas, react for 5 hours, stop the reaction, remove most of the acetic acid under reduced pressure, then add ethyl acetate and water for extraction and liquid separation, The organic phase was collected, dried, concentrated, and the residue was separated on a silica gel column to obtain 29 g of dichlorodimethy...

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