Aminothiazole compound dehydration and alkylation method

An aminothiazole and compound technology, applied in the field of synthesis of N-alkylaminothiazole and derivatives thereof, achieves the effects of reducing synthesis cost, good research and industrial application prospects, and mild reaction conditions

Inactive Publication Date: 2013-06-12
WENZHOU UNIVERSITY
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Problems solved by technology

According to reports, using metallic copper or iridium catalysts, alcohols as alkylating reagents, the alkylation reaction can be carried out on the exocyclic amino group with opposite selectivity to obtain 2-(N-alkylamino) benzothiazole compounds, but these There are still many obvious shortcomings in the method of borrowing hydrogen (especially the reaction catalyzed by metal iridium)

Method used

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  • Aminothiazole compound dehydration and alkylation method
  • Aminothiazole compound dehydration and alkylation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Preparation of N-(4-methoxybenzyl)-2-aminobenzothiazole by the reaction of 2-aminobenzothiazole and 4-methoxybenzyl alcohol

[0020]

[0021] Add 2-aminobenzothiazole (1mmol), 4-methoxybenzyl alcohol (1.5mmol, 1.5equiv.), NaOH (20mol%) in turn into a 20mL reaction tube, and directly seal and heat to 120°C for 3h under air , The conversion rate of the reaction was 99% as measured by GC-MS. The product was separated and purified by column chromatography, and the separation yield was 95%. 1 HNMR (500MHz, d 6 -DMSO):δ8.44(t,J=5.0Hz,1H),7.67(d,J=8.0Hz,1H),7.41(d,J=8.0Hz,1H),7.32(d,J=9.0Hz ,2H),7.25-7.21(m,1H),7.04-7.01(m,1H),6.92(d,J=8.5Hz,2H),4.53(d,J=5.5Hz,2H),3.74(S, 3H). 13 C NMR (125.4MHz, d 6 -DMSO): δ166.3, 158.6, 152.7, 130.9, 130.6, 129.0, 125.7, 121.07, 121.05, 118.2, 113.9, 55.2, 46.9. MS (EI): m / z (%) 270 (16, M+), 219 ( 4), 207(3), 121(100), 91(5), 77(8), 69(7), 63(5).

Embodiment 2

[0023] Preparation of N-(3-methoxybenzyl)-2-aminobenzothiazole by the reaction of 2-aminobenzothiazole and 3-methoxybenzyl alcohol

[0024]

[0025] Add 2-aminobenzothiazole (1mmol), 3-methoxybenzyl alcohol (1.5mmol, 1.5equiv.), NaOH (20mol%) in sequence to a 20mL reaction tube, and directly seal and heat to 120°C for 3h under air , GC-MS measured the conversion rate of 90%. The product was separated and purified by column chromatography, and the separation yield was 74%. 1 HNMR (500MHz, CDCl 3 ):δ7.55(d,J=8.0Hz,1H),7.38(d,J=8.0Hz,1H),7.26-7.23(m,2H),7.07-7.04(m,1H),6.98-6.93( m,3H),6.82(dd,J=2.5Hz,J=8.5Hz,1H),4.58(s,2H),3.74(s,3H). 13 CNMR (125.4MHz, CDCl 3 ):δ168.0,160.0,152.2,139.1,130.4,129.9,126.0,121.5,120.8,119.9,118.8,113.4,113.2,55.2,49.4.MS(EI):m / z(%)270(76,M+), 269(24), 255(8), 239(5), 136(62), 121(100), 91(49), 78(25), 77(23), 65(19).

Embodiment 3

[0027] Preparation of N-(2-methoxybenzyl)-2-aminobenzothiazole by the reaction of 2-aminobenzothiazole and 2-methoxybenzyl alcohol

[0028]

[0029] 2-Aminobenzothiazole (1mmol), 2-methoxybenzyl alcohol (1.5mmol, 1.5equiv.), NaOH (20mol%) were added sequentially into a 20mL reaction tube, and directly sealed and heated to 120°C for 3h under air , The conversion rate of the reaction was 99% as measured by GC-MS. The product was separated and purified by column chromatography, and the separation yield was 92%. 1 HNMR (500MHz, CDCl 3 ):δ7.54(d,J=8.0Hz,1H),7.46(d,J=8.0Hz,1H),7.36(dd,J=1.0Hz,J=7.5Hz,1H),7.26-7.24(m ,2H),7.06-7.02(m,1H),6.92-6.86(m,2H),6.48(b,1H),4.59(s,2H),3.82(s,3H). 13 CNMR (125.4MHz, CDCl 3):δ167.8,157.5,152.4,130.4,129.4,129.1,125.8,125.6,121.3,120.7,120.5,118.7,110.3,55.3,45.4.MS(EI):m / z(%)274(52,M+), 270(37),255(11),239(42),207(14),151(10),131(22),121(88),119(13),105(8),91(100), 77(13),69(32),65(22),

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Abstract

The invention provides an aminothiazole compound dehydration and alkylation method. According to the method, any transition metal or non-transition metal catalyst is not required, and the aminothiazole compound can be directly reacted in the presence of a little alkali under the inert gas protection or air. The reaction conditions are mild, the reaction is easy to operate, the product is simply separated and purified, and the product recovery rate is high. The low-price readily available alcohol serves as an alkylating agent, and the synthesis cost is greatly reduced. In addition, the reaction is carried under solvent-free conditions, and the possible pollution of the organic solvent on the environment can be reduced to a certain degree; and moreover, the reaction requirements on the reaction conditions are low, the reaction can be performed under air conditions, and the method has good research and industrial application prospect.

Description

technical field [0001] The present invention relates to a synthesis method of N-alkylaminothiazole and its derivatives, in particular to a method for synthesizing N-alkylaminothiazole and its derivatives through dehydration N-alkylation reaction of alcohol and 2-aminothiazole compounds Methods. Background technique [0002] The N-alkylation reaction of amine compounds is one of the most important and basic methods for C-N bond formation and synthesis of amine derivatives. The traditional N-alkylation reaction uses a halogenated hydrocarbon as an alkylating agent and is realized by the Hofmann reaction. However, this method has many disadvantages. It requires the use of a large amount of alkali, produces a lot of waste, and has low reaction selectivity, resulting in difficulty in product separation. In recent years, through the "hydrogen borrowing" method catalyzed by transition metals, green, low-toxic and low-priced alcohol compounds can be used to replace halogenated hydr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D277/82C07D417/12C07D277/42
Inventor 徐清李双艳李强
Owner WENZHOU UNIVERSITY
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