Preparation method for bromine benzyls compound

The technology of a compound, bromosuccinimide, is applied in the field of organic synthesis, which can solve the problems of long time period, complicated operation and low selectivity, and achieve short reaction time period, mild reaction conditions and good reaction selectivity Effect

Active Publication Date: 2012-07-18
湖北潜龙药业有限公司
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Problems solved by technology

Although the reaction cycle of this preparation method is short, the selectivity is low and accompanied by a large number of by-products, the yield is low, it is not easy to control, the energy consumption is large and it will also bring serious environmental pollution.
In addition, the reaction selectivity of benzyl bromide prepared by the photobromination method using carbon tetrachloride as a solvent in a traditional reactor is good, easy to control and low in energy consumption, but there are still many wastes, low reaction efficiency, and time cycle Long and other unfavorable factors limit industrialized production (Tetrahedron, 2009, vol(65), 4429-4439)
The above two methods will be at the expense of environmental consumption, and the operation is complicated in the industrialization process, and because benzyl bromide itself has a strong irritant, it brings great inconvenience to the operation.

Method used

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  • Preparation method for bromine benzyls compound
  • Preparation method for bromine benzyls compound
  • Preparation method for bromine benzyls compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Embodiment 1: the preparation of 4-acetyl benzyl bromide

[0017] exist figure 1 In the photoreaction equipment shown, add 10kg p-methylacetophenone, 40kg water by feeding system 2, open circulation pump 7 and make reaction system form turbulent flow in fully transparent tube 5, turn on 10 lamps of 105w (that is, High-power lighting 6), the temperature is maintained at 20-50°C by the temperature control system 3, and then 13.6kg NBS and 0.5kg AIBN are added by the feeding system 2, and the reaction is terminated after 12 hours. Emit whole reaction liquid from ball valve 4, use the NaHCO that mass fraction is 10% 3 The reaction liquid was washed with aqueous solution, and the lower organic phase was collected by liquid separation, then heated and dissolved with ethanol until clarified, and 14.5 kg of light yellow crystals were precipitated by cooling down, with a yield of 91.7% and a purity of 97% by HPLC. The melting point is 36-38°C. 1 H NMR (600MHz, CDCl 3 )δ: 7...

Embodiment 2

[0018] Embodiment 2: the preparation of 4-tert-butylbenzyl bromide

[0019] exist figure 1 In the photoreaction equipment shown, add 15kg 4-tert-butyltoluene, 35kg water by feeding system 2, open circulation pump 7 and make reaction system form turbulent flow in fully transparent tube 5, turn on 10 lamps of 105w (that is, High-power lighting 6), the temperature is maintained at 20-50°C by the temperature control system 3, and then 18kg NBS is added from the feeding system 2, and the reaction is terminated after 4 hours without a catalyst. Emit whole reaction liquid from ball valve 4, use the NaHCO that mass fraction is 10% 3 The reaction solution was washed with aqueous solution, the lower organic phase was collected by liquid separation, and then washed with n-hexane to obtain 20.5 kg of colorless oily liquid with a yield of 89.1% and a purity of 96% by HPLC. no D 20 = 1.5448; 1 H NMR (600MHz, CDCl 3 )δ: 7.56 (d, J = 7.8Hz, 2H), 7.43 (d, J = 7.8Hz, 2H), 4.46 (s, 2H), ...

Embodiment 3

[0020] Embodiment 3: the preparation of 4-methoxybenzyl bromide

[0021] exist figure 1 In the photoreaction equipment shown, add 20kg 4-methoxytoluene, 40kg water by feeding system 2, open circulation pump 7 and make reaction system form turbulent flow in fully transparent tube 5, turn on 10 lamps of 105w (that is, High-power lighting 6), the temperature is maintained at 20-50°C by the temperature control system 3, and then 13.6kg NBS and 0.5kg AIBN are added from the feeding system 2, and the reaction is completed after 15 hours of reaction. Emit whole reaction liquid from ball valve 4, use the NaHCO that mass fraction is 10% 3 The reaction liquid was washed with aqueous solution, the lower organic phase was collected by liquid separation, and then washed with n-hexane to obtain 20.5 kg of oily liquid with a yield of 85.5% and a purity of 95% by HPLC. no D 20 = 1.5819; 1 H NMR (600MHz, CDCl 3 )δ: 7.43 (d, J = 7.8 Hz, 2H), 7.12 (d, J = 7.8 Hz, 2H), 4.46 (s, 2H), 3.83 ...

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Abstract

The invention provides a preparation method for a bromine benzyls compound, wherein the preparation method for the bromine benzyls compound expressed by formula (I) comprises the following steps: under an illumination condition, causing the compound expressed by formula (II) to react with N-bromosuccinimide in a system taking water as a solvent, thereby obtaining the compound expressed by the formula (I), wherein R1 or R2 is independent H, CH3CO, tertiary butyl, NHOCCH3, alkoxy with 1-4 carbon atoms or CN. The preparation method provided by the invention has the advantages of simple processing operation, low cost, short reaction time period, mild reaction condition, easiness in controlling, excellent reaction selectivity, high yield of products, low energy consumption, and small environmental pollution. Compared with the traditional preparation method, especially under the environment advocating green chemistry at present, the preparation method provided by the invention has the advantages that the prospect is excellent, the preparation method is efficiently applied to the preparation of synthesizing intermediate by using the bromine benzyls compound, and raw materials are supplied to various fields, such as medicines, pesticides, dyes and auxiliary chemicals.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for preparing benzyl bromide compounds through light-induced green industrialization. Background technique [0002] Benzyl bromide is an important intermediate in organic synthesis, and is widely used in various fields such as medicine, pesticide, dyestuff and chemical auxiliary. An existing preparation method of benzyl bromide is a catalytic bromination method using an aprotic solvent such as carbon tetrachloride as a medium or a solvent-free method, usually under severe conditions of reflux, adding N-bromosuccinyl in batches Amine (NBS) or slow dropwise addition of Br 2 Preparation of benzyl bromide (Wilhelm WennerBis(bromomethyl)compounds, J.Org.Chem., 1952, 17, 523-8; Phosphorus, Sulfur and Silicon and the Related Elements, 1993, vol(85), 225-231; Tetrahedron Letters, 1997, vol. (38), 8557-8560). Although the reaction cycle of the preparation method is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/63C07C49/78C07C17/35C07C22/04C07C41/22C07C43/225C07B39/00
Inventor 张发明宋伟雷明刘文刘燕
Owner 湖北潜龙药业有限公司
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