Oxazine near-infrared fluorescent dye as well as preparation method and application thereof

[0030] Example 1

[0031] Synthesis of YQN-3 (i.e. compound I-1)

[0032] 1. Take 1.50g of m-bromoanisole, 0.73g of cyclopropylamine, 1.36g of potassium tert-butoxide, and 0.05g of tetrakis(triphenylphosphine)palladium in toluene (8ml) and heat to reflux at 80°C for 8h. After the reaction, the solution was spin-dried, and the remaining solid was purified by column chromatography to obtain N-cyclopropyl-3-methoxyaniline as a brown oily liquid. m/z: 164.14.

[0033] 2. Dissolve 200 mg of N-cyclopropyl-3-methoxyaniline in 2M ice-cold dilute hydrochloric acid solution (5 ml), add 103 mg of sodium nitrite into the solution while keeping the solution temperature below 5°C. After the addition, the solution was stirred for another 2 h, then it was dropped into a saturated potassium carbonate solution, extracted with ethyl acetate, the organic layer was dried with anhydrous sodium sulfate, and spin-dried to obtain a yellow-green solid N-cyclopropyl-3-methoxy Base-4-nitrosoaniline. m/z: 192.09.

[0034] 3. At 80°C, dissolve 86 mg of m-hydroxy-N.N-diethylaniline in i-PrOH/H 2 O (9:1, 4ml) for 30min. N-cyclopropyl-3-methoxy-4-nitrosoaniline 100mg and perchloric acid (70%, 47μl) in i-PrOH/H 2 The suspension in O (9:1, 4ml) was added to the above solution. The resulting mixture was then stirred for 8h. During this time, the color of the reaction mixture changed from brown to green and finally dark blue. Then the water in the mixture was removed with anhydrous sodium sulfate, and after being spin-dried, the remaining solid was purified by column chromatography to obtain dark blue solid YQN-3. Its mass spectrometry and H NMR spectrum are as figure 1 As shown, the specific data are as follows: m/z: 308.22, 1H NMR (400MHz, DMSO-d6) δ9.53 (s, 1H), 7.80 (d, J=9.6Hz, 1H), 7.73 (d, J=8.9 Hz, 1H), 7.43(dd, J=9.7, 2.7Hz, 1H), 7.11(d, J=9.1Hz, 1H), 7.04(d, J=2.7Hz, 1H), 6.98(t, J=2.4 Hz, 1H), 3.76(q, J=7.1Hz, 4H), 2.89(tq, J=7.2, 3.6Hz, 1H), 1.26(t, J=7.1Hz, 6H), 0.97(dt, J=6.9 , 3.4Hz, 2H), 0.76-0.64(m, 2H).

[0035] Example 2

[0036] Synthesis of YQN-4 (i.e. compound I-2)

[0037] The synthesis of YQN-4 refers to Example 1. Its mass spectrometry and H NMR spectrum are as figure 2 As shown, the specific data are as follows: m/z: 322.21, 1H NMR (400MHz, DMSO-d6) δ9.67 (d, J=6.4Hz, 1H), 7.79 (d, J=9.4Hz, 1H), 7.73 ( d, J=9.3Hz, 1H), 7.46-7.31(m, 1H), 7.15(d, J=9.3Hz, 1H), 6.97(s, 1H), 6.67(s, 1H), 4.43-4.25(m , 1H), 3.74(q, J=7.1Hz, 4H), 2.47(d, J=9.3Hz, 2H), 2.09(p, J=9.6Hz, 2H), 1.84(q, J=8.6Hz, 2H ), 1.25(t, J=7.0Hz, 6H).

[0038] Example 3

[0039] Synthesis of YQN-5 (i.e. compound I-3)

[0040] The synthesis of YQN-5 refers to Example 1. Its mass spectrometry and H NMR spectrum are as image 3 As shown, the specific data are as follows: m/z: 336.22, 1H NMR (400MHz, DMSO) δ9.31 (s, 1H), 7.79 (d, J=9.5Hz, 1H), 7.72 (d, J=9.4Hz, 1H), 7.37(d, J=8.6Hz, 1H), 7.17(d, J=10.0Hz, 1H), 7.11-6.96(m, 1H), 6.95(d, J=16.1Hz, 1H), 3.73( dd, J=14.0, 6.9Hz, 4H), 1.95(d, J=9.9Hz, 2H), 1.76(d, J=13.2Hz, 2H), 1.64(d, J=13.7Hz, 1H), 1.36( dt, J=22.3, 11.5Hz, 4H), 1.23(t, J=7.0Hz, 6H).