Oxazolopyridine quaternary ammonium salt compound and preparation method and application thereof

[0048] Example 1 Preparation of Compound I-1

[0049]

[0050] Dissolve compound S-1 in dry toluene, add excess trifluoroacetic acid to it, heat to 50℃, keep dry, react overnight, spin-dry the excess acid and solvent, and wash with ether to obtain pure compound I-1 , The yield was 86%. 1 HNMR (400MHz, chloroform-d) δ 7.62 (dd, J = 7.0, 2.0 Hz, 1H), 7.52 (ddt, J = 8.7, 6.6, 2.7 Hz, 1H), 6.75 (d, J = 9.1 Hz, 1H ), 6.47(q,J=7.1Hz,1H), 6.08–5.97(m,1H), 3.78(q,J=11.5,9.8Hz,2H), 3.37(s,3H). 13 C NMR(125MHz, CDCl 3 )δ159.91,149.11,137.12,119.27,110.64,93.01,75.74,58.15.MS(EI):265.

[0051] Example 2 Preparation of Compound I-2

[0052]

[0053] The compound S-2 was dissolved in dry anhydrous ether, and an excessive amount of concentrated hydrochloric acid was added to it. A large amount of yellow solid precipitated immediately. After stirring for 3 hours, it was filtered and washed with anhydrous ether to obtain the pure compound I-2. Yield Is 92%. 1 H NMR(400MHz, chloroform-d)δ7.66(d,J=7.3Hz,1H), 6.88(dd,J=1.9,1.0Hz,1H), 6.43(dd,J=7.3,2.0Hz,1H) ,6.07(dd,J=4.8,3.6Hz,1H), 3.87–3.70(m,2H), 3.45(s,3H) 13 C NMR(125MHz, CDCl 3 )δ160.93,141.24,140.97,133.41,122.63,120.45,117.99,100.85,84.91,57.37,43.98.MS(EI)255.

[0054] Example 3 Preparation of Compound I-3

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[0056] The preparation method was the same as that in Example 2, and compound S-2 was replaced with compound S-3 to obtain compound I-3, and the yield was 99%. 1 HNMR(400MHz, chloroform-d)δ9.28(s,1H), 8.60(dd,J=7.2,2.2Hz,1H), 7.77(dd,J=6.8,1.9Hz,1H), 6.56(t,J =6.9Hz,1H), 6.22–6.09(m,1H), 5.97(s,1H), 3.93–3.69(m,2H), 3.46(s,3H). 13 C NMR(125MHz, CDCl 3 )δ164.76,161.45,144.37,135.61,120.97,106.16,85.37,57.49,44.09.MS(ESI)195.