Novel synthesis method of 3,4-dichloropyridazine
A technology of dichloropyridazine and a synthesis method, which is applied in the field of preparation of chemical intermediates, can solve problems such as being unsuitable for scale-up production, complex preparation process, and tedious post-processing, and achieves good operability, simple post-processing, and easy raw materials. the effect
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Embodiment 1-5
[0027] Preparation of Example 1-5 Compound 2
[0028]
[0029] Compound 1 (100 g, 0.61 mol) was dissolved in isopropanol (800 ml), and hydrazine hydrate (80%, mass percent) (33.5 g, 0.67 mol) was slowly added to the reaction liquid, and reacted at room temperature for 6 hours. After the completion of the reaction as detected by TLC, the reaction solution was filtered, and the obtained crude product was washed twice with ethyl acetate (150 ml), and dried to obtain the product compound 2 (90 g, 0.56 mol), with a yield of about 92%. In this reaction step, the product yields obtained by changing the molar ratio of the reactants, the reaction temperature and the reaction time are listed in Table 1.
[0030] Table 1
[0031]
[0032]
[0033] It can be seen from Table 1 that in the synthesis of compound 2 from compound 1, the molar ratio of hydrazine hydrate to compound 1 is 1.1:1, the reaction temperature is 25-30°C, and the reaction time is 6h. Compound 2 obtained under ...
Embodiment 6-10
[0034] Preparation of Example 6-10 Compound 3
[0035]
[0036] Compound 2 (90 g, 0.56 mol) was added to THF (1 L), manganese dioxide (195 g, 2.24 mol) was added in batches under ice-cooling (0-10° C.), and reacted at room temperature for 8 hours. After the completion of the reaction detected by TLC, the reaction solution was filtered and the filtrate was concentrated to obtain crude product 3, which was purified by column chromatography to obtain pure compound 3 (28 g, 0.21 mol). (If the crude product is directly used in the next step without purification, the product components are very miscellaneous, and it is difficult to obtain further products). The yield is about 37.5%.
[0037] Compound 3: 1 H NMR (400MHz, DMSO): δ 13.53 (s, 1H), 7.86 (d, J=4.4Hz, 1H), 7.76 (d, J=4.4Hz, 1H).
[0038] In this reaction step, the product yields obtained by changing the molar ratio of the reactants, the reaction temperature and the reaction time are listed in Table 2.
[0039] Table...
Embodiment 11-15
[0042] Preparation of Example 11-15 Compound 4
[0043]
[0044] Compound 3 (25g, 0.19mol) was added to acetonitrile (200ml), then phosphorus oxychloride (73g, 0.48mol) was added, and the reaction was refluxed at 80°C for 3 hours. After the reaction was complete as detected by TLC, the reaction solution was cooled to room temperature. Pour the reaction solution directly into ice water (200ml), add sodium bicarbonate to adjust to weak alkalinity (pH about 7-8), then extract twice with ethyl acetate (300ml), combine the organic phases, and use After washing with saturated brine (400 ml), and drying over anhydrous sodium sulfate, the organic phase was concentrated. The obtained crude product was purified by column chromatography to obtain compound 4 (18.0 g, 0.12 mol). The yield is about 64%.
[0045] Compound 4: 1 H NMR (600 MHz, CDCl3): δ = 9.02 (d, J = 5.3, 1H), 7.61 (d, J = 5.3, 1H).
[0046] In this reaction step, the product yields obtained by changing the molar rati...
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