C3 aryl formyloxylated 4H-pyrido [1, 2-a] pyrimidine-4-ketone derivative and synthesis method thereof

Abstract

The invention discloses a C3 aryl formyloxylated 4H-pyrido [1, 2-a] pyrimidine-4-ketone derivative and a synthesis method thereof, and belongs to the technical field of organic photocatalytic synthesis. Aiming at the problems that a noble metal catalyst, a strong oxidant, a photosensitizer which pollutes the environment, a toxic solvent and the like exist in the current C3-H functionalization of a 4H-pyrido [1, 2-a] pyrimidine-4-ketone derivative and the aryl formyloxylation of a heterocyclic compound, the method disclosed by the invention is characterized in that the 4H-pyrido [1, 2-a] pyrimidine-4-ketone derivative is synthesized under the condition of room-temperature air and the irradiation of 410-415nm purple light. The preparation method comprises the following steps: reacting 4H-pyridino [1, 2-a] pyrimidine-4-ketone with a peroxide aryl formyl compound in a dimethyl carbonate solvent to generate a C3 aryl formyloxylated 4H-pyridino [1, 2-a] pyrimidine-4-ketone derivative; the method does not need to add any oxidant or photocatalyst, and has the advantages of simplicity and convenience in operation, mild conditions, easily available raw materials, environmental friendliness, excellent compatibility of substrate functional groups, high reaction yield and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of organic photocatalytic synthesis, and specifically relates to a C3 aromatic formyloxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative and a synthesis method thereof. Background Art

[0002] As a common heterocyclic compound, pyrido[1,2-a]pyrimidin-4-one has good biological and pharmaceutical activities, making it an important heterocyclic skeleton structure in drug development. For example, 2,3-diaryl-4H-pyrimido[1,2-a]pyrimidin-4-one derivatives can be used as inhibitors of endothelial cell dysfunction and smooth muscle cell activators. In addition, C3 arylated pyridin[1,2-a]pyrimidin-4-one has a variety of biological activities, such as regulators of platelet activation and aggregation, anti-inflammatory agents, anti-tuberculosis agents, CXCR3 antagonists, anti-allergic activity, efflux pump inhibition, and acetylcholinesterase, antioxidants, antipsychotic drugs, etc. At present, the functionalization of the C3 position of 4H-pyrido[1,2-a]pyrimidin-4-one mainly includes: C3 aryl substitution, C3 dialkyl phosphite substitution, C3 arylthio (selenium) substitution, C3 aryl substitution, etc. However, the above-mentioned method for functionalizing the C3 position of 4H-pyrimidine [1,2-a] pyrimidin-4-one derivatives has the disadvantages of harsh reaction conditions, the need to add precious metal catalysts (palladium acetate / silver nitrate, J. Org. Chem. 2015, 80, 8482–8488; Asian J. Org. Chem. 2021, 10, 1660–1664), strong oxidants (K2S2O8, PIFA / I2, J. Org. Chem. 2021, 10, 2911–2915; Adv. Synth. Catal. 2021, 363, 2148–2156), a narrow substrate range, the addition of environmentally polluting photosensitizers (J. Org. Chem., 2023, 88, 13: 9537–9542), and the use of environmentally unfriendly organic solvents (European Journal of Organic Chem. 2015, 80, 13: 9537–9542). Chemistry, 2023, 26(29), e202300268) and other deficiencies.

[0003] The CH aryloxylation of heterocyclic compounds has attracted more and more attention from scientists. Because it can directly prepare aryl carboxylate products, it has potential applications. For example, aryl carboxylate is used as an alternative electrophilic reagent in palladium-free cross-coupling reactions, and converted into potential phenolic compounds. At present, the CH aryloxylation of heterocyclic compounds mainly includes the preparation of 8-aminoquinoline with aromatic acid or aryloxy compounds catalyzed by ferric chloride or copper acetate (Org. Biomol. Chem., 2017, 15, 9200; Org. Lett, 2017, 19, 3636; Org. Biomol. Chem., 2017, 15, 531). However, the above methods have the disadvantages of using transition metal catalysts, harsh reaction conditions, narrow substrate range, low yield, and the use of toxic organic solvents. Summary of the invention

[0004] In view of the problems of using noble metal catalysts, strong oxidants, photosensitizers that pollute the environment, and toxic solvents in the current C3-H functionalization of 4H-pyrido[1,2-a]pyrimidin-4-one derivatives and the aromatic formyloxylation of heterocyclic compounds, the present invention provides a C3 aromatic formyloxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative and a photocatalytic synthesis method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A C3 aromatic carboxylate oxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative, wherein the C3 aromatic carboxylate oxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative has the following structure (I):

[0007]

[0008] R 1 =H, 6-methyl, 7-methyl, 8-methyl, 7-fluoro, 7-chloro, 7-bromo, 7-ester, 7-CF3; R 2 = methyl, phenyl, p-chlorophenyl; Ar = 2-methylphenyl, 3-methylphenyl, p-methoxyphenyl, p-fluorophenyl, 3-fluorophenyl, p-chlorophenyl, 3-chlorophenyl, p-bromophenyl, p-trifluoromethylphenyl, p-nitrophenyl.

[0009] A method for preparing a C3 aromatic carboxylate oxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative: 4H-pyrido[1,2-a]pyrimidin-4-one reacts with a peroxide aromatic carboxylate compound in an organic solvent under room temperature and air conditions and under 410-415 nm violet light irradiation to generate a C3 aromatic carboxylate oxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative; the method does not require the addition of any oxidant and photocatalyst and has the advantages of simple operation, mild conditions, readily available raw materials, green environmental protection, excellent substrate functional group compatibility, high reaction yield, etc.

[0010] Furthermore, the 4H-pyrido[1,2-a]pyrimidin-4-one compound is shown in the following structural formula II:

[0011]

[0012] Among them, R 1 =H, 6-methyl, 7-methyl, 8-methyl, 7-fluoro, 7-chloro, 7-bromo, 7-ester, 7-CF3; R 2 = methyl, phenyl, p-chlorophenyl;

[0013] Further, the aryl formyl peroxide compound is shown in the following structural formula III:

[0014] Among them, Ar is 2-methylphenyl, 3-methylphenyl, p-methoxyphenyl, p-fluorophenyl, 3-fluorophenyl, p-chlorophenyl, 3-chlorophenyl, p-bromophenyl, p-trifluoromethylphenyl, or p-nitrophenyl.

[0015] Furthermore, the molar ratio of the 4H-pyrido[1,2-a]pyrimidin-4-one to the aryl formyl peroxide compound is 1:1 to 1:2.

[0016] Furthermore, the concentration of the 4H-pyrido[1,2-a]pyrimidin-4-one compound in the dimethyl carbonate solvent is 0.1 mol / L to 0.5 mol / L.

[0017] Furthermore, the organic solvent is one of ethyl acetate, dimethyl carbonate, ethanol and DMSO, wherein dimethyl carbonate is preferred.

[0018] Furthermore, the wavelength of the ultraviolet light source is 410-415 nm, and the light intensity is 5-8 W, with 6 W being preferred.

[0019] The method of the present invention does not require the use of an externally added catalyst. The results of extensive research by the inventors show that the dimethyl carbonate solution of 4H-pyrido[1,2-a]pyrimidin-4-one and its derivatives have good absorption effects on visible light in the 410-415nm band, showing photosensitivity, and can be used as a good photosensitive catalyst for the reaction. During the reaction, the 4H-pyrido[1,2-a]pyrimidin-4-one compound and the peroxide aryl formyl compound can undergo a CH functionalization reaction under the irradiation of 410-415nm purple light to first obtain a small amount of 3-aryl formyloxy-4H-pyrido[1,2-a]pyrimidin-4-one compound, and the 3-aryl formyloxy-4H-pyrido[1,2-a]pyrimidin-4-one compound is used as a photosensitive catalyst to promote the reaction, thereby greatly improving the reaction efficiency and shortening the reaction time.

[0020] The present invention also proposes a reasonable reaction mechanism, which is described by taking the reaction of 2-phenyl 4H-pyrido[1,2-a]pyrimidin-4-one compound (1) and benzoyl peroxide (2) as an example. The 2-phenyl 4H-pyrido[1,2-a]pyrimidin-4-one compound 1a is used as a photosensitizer to catalyze the reaction. Under the action of light of 410 to 415 nm, the ground state compound 1a is excited and converted into a highly active excited state compound 1a*. Benzoyl peroxide 2a and the excited state compound 1a* generate benzoate anions, benzoyloxy free radicals and 2-phenyl 4H-pyrido[1,2-a]pyrimidin-4-one free radical cations through electron transfer. The benzoyloxy free radical and the ground state 2-phenyl 4H-pyrido[1,2-a]pyrimidin-4-one compound 1a undergo free radical addition to generate a free radical intermediate IM1. The free radical intermediate A undergoes a single electron transfer reaction with the 2-phenyl 4H-pyrido[1,2-a]pyrimidin-4-one free radical cation to generate the cationic intermediate IM2 and the ground state 2-phenyl 4H-pyrido[1,2-a]pyrimidin-4-one compound 1a. The cationic intermediate IM2 undergoes dehydrogenative aromatization under the action of benzoate anion to generate the target product 2-phenyl-3-arylformyloxy-4H-pyrido[1,2-a]pyrimidin-4-one compound 3a. The 2-phenyl-3-arylformyloxy-4H-pyrido[1,2-a]pyrimidin-4-one compound 3a obtained in the reaction also participates in the reaction as a photosensitizer.

[0021]

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] Compared with the prior art, the technical solution of the present invention brings the following beneficial technical effects:

[0024] (1) The present invention uses an LED with a power of about 6W and a wavelength of 410-415nm as a light source, which is safe, energy-saving, cheap and readily available;

[0025] (2) The aryl formyl peroxide compound used in the present invention is cheap and readily available, and the present invention has a wide selectivity for the aryl formyl peroxide compound and good functional group compatibility.

[0026] (3) The present invention does not use additives, transition metal catalysts, or external photosensitizers, and has simple operation, mild conditions, high reaction selectivity, and easy separation and purification of the product with high yield. The prepared C3 aromatic carboxylic acid oxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative is a new compound, which has certain feasibility for realizing industrial production and provides an important reference for the photocatalytic CH functionalization of other heterocyclic compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The invention provides a photocatalytic synthesis route for preparing C3 aromatic carboxylic acid oxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivatives.

[0028] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of 2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one.

[0029] Figure 3 This is the carbon NMR spectrum of 2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one.

[0030] Figure 4 It is the UV image of 2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one 1a and 2-phenyl-3-arylformyloxy-4H-pyrido[1,2-a]pyrimidin-4-one compounds.

[0031] Figure 5 These are the fluorescence images of 2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one 1a and benzoyl peroxide compound 2a with different concentrations added.

[0032] Figure 6 This is the single crystal diffraction pattern of 7-methyl-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one. DETAILED DESCRIPTION

[0033] In order to gain a deeper understanding of the present invention, we will provide a comprehensive and detailed description of the present invention. However, the present invention has multiple implementations and is not limited to the specific examples listed herein. The presentation of these examples is intended to deepen the comprehensive understanding of the disclosure of the present invention.

[0034] Comparative Example:

[0035] The following control experimental groups 1 to 19 all react according to the following reaction equation:

[0036]

[0037] The specific operation steps are as follows: 2-phenyl-4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol), benzoyl peroxide (0.3 mmol), and 1 mL of dimethyl carbonate were added to a 10 mL reaction tube in sequence. The reaction was allowed to proceed under LED light at room temperature. After the reaction was completed, the mixture was cooled to room temperature and the yield was analyzed by GC-MS.

[0038]

[0039] Experiments 1 to 7 in the above table investigated the effect of the reaction medium on the reaction and the effect of different solvents on the reaction yield. When the reaction solvents were dichloromethane (CH2Cl2), tetrahydrofuran (THF), acetonitrile (MeCN), ethanol (EtOH) and dimethyl sulfoxide (DMSO), the reaction yield was very low. When ethyl acetate (EtOAc) was used as the reaction solvent, the yield increased. Unexpectedly, when the green solvent dimethyl carbonate (DMC) was used, the yield of the target product was the highest, reaching 88%. Therefore, DMC was selected as the optimal reaction solvent. Experiments 8 to 12 in the above table investigated the effect of light of different wavelengths on the reaction. It can be seen from the table that the yields under light irradiation of other wavelengths are lower than the yields under irradiation of a wavelength of 410 to 415 nm.

[0040] In the above table, experimental groups 13 to 14 investigated the effects of no light and nitrogen conditions on the reaction. The experiments showed that the reaction could not occur under no light conditions and the reaction could not occur under nitrogen conditions.

[0041] In the table above, experimental groups 13 to 19 investigated the effects of light power and reaction time. The experiment showed that 6W power was the best light power. When the power was reduced to 5W, the yield decreased. When the power was increased to 8W, the yield showed a downward trend. The best reaction time was 3h, and the yield decreased when the reaction time was shortened or extended.

[0042] The synthetic route of the C3 aromatic carboxylate 4H-pyrido[1,2-a]pyrimidin-4-one derivative provided by the present invention is as follows: Figure 1 shown.

[0043] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol), aryl formyl peroxide compound (0.4 mmol), and 1 mL dimethyl carbonate were added to a 10 mL reaction tube in sequence. The reaction was carried out under blue light at room temperature for 2 to 5 hours. After the reaction was completed, the mixed solution was dried by spin drying and column chromatography was performed to obtain a C3 aryl formyloxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative.

[0044] The present invention is further described below in conjunction with specific preparation examples 1 to 23:

[0045] Example 1

[0046] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out for 3h under violet light (6W, 410-415nm) at room temperature. After the reaction was completed, the mixed solution was dried and column chromatography was performed to obtain a white solid 2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 88%. The target product has the following structural formula:

[0047]

[0048] Mp=108-109℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.04(d,J=7.00Hz,1H),8.21(d,J=7.00Hz,2H),7.96-7.95(m,2H),7.80-7.76( m,2H),7.64(t,J=7.50Hz,1H),7.51(t,J=8.00Hz,2H),7.44(t,J=8.00Hz,3H),7.19(t,J=6.75Hz,1H); 13 C NMR (500MHz, CDCl3): δ164.1,154.5,153.9,148.1,135.4,135.3,133.7,130.5,130. 1,129.0,128.7,128.5,128.4,127.7,127.3,126.7,115.4; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 21 H 15 N2O3343.1077, found 343.1076.

[0049] Example 2

[0050] In a 10 mL reaction tube, 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =6-CH3,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under violet light (10W, 6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried and column chromatography was performed to obtain a yellow solid 6-methyl-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 78%. The target product has the following structural formula:

[0051]

[0052] Mp=105-106℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ8.94 (d, J = 7.00Hz, 1H), 8.20 (d, J = 8.00Hz, 2H), 7.94 (t, J = 4.00Hz, 2H), 7.63 (t, J = 7. 25Hz,1H),7.57(s,1H),7.50(t,J=7.75Hz,2H),7.44(t,J=6.00Hz,3H),7.01(d,J=7.50Hz,1H),2.52(s,3H); 13 C NMR (500MHz, CDCl3): δ164.2,154.8,153.9,148.1,147.5,135.4,133.7,130.5,129.9,1 28.9,128.8,128.5,128.4,127.0,126.6,124.7,118.2,21.4; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 22 H 17 N2O3357.1234, found 357.1233.

[0053] Example 3

[0054] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =7-CH3,R 2=Ph), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried and column chromatography was performed to obtain a yellow solid 7-methyl-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 75%. The target product has the following structural formula:

[0055]

[0056] Mp=128-129℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ8.86 (s, 1H), 8.20 (d, J = 8.00Hz, 2H), 8.11 (d, J = 7.5Hz, 1H), 7.94 (d, J = 6.00Hz, 1H), 7 .73(d,J=11.50Hz,1H),7.63(d,J=8.50Hz,2H),7.51(d,J=8.00Hz,3H),7.44(d,J=6.50Hz,2H),2.47(s,3H); 13 C NMR (500MHz, CDCl3): δ164.1,154.2,153.7,147.1,138.5,135.3,133.7,133.5,131.8,130.5,130.1,129.9,1 29.2,128.9,128.8,128.5,128.4,127.9,127.6,126.1,126.0,125.8,124.7,18.4; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 22 H 17 N2O3357.1234, found 357.1234.

[0057] Single crystal data: C 22 H 16 N2O3; Mr=356.37, monoclinic, space group P 121 / c 1, T=200.00K;Z=4;Reflections collected / unique,15457 / 3514,R int =0.0945, R1=0.0388, wR2=0.1034; GOF=1.042.

[0058] Example 4

[0059] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =8-CH3,R 2 =Ph), aryl formyl peroxide (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried and column chromatography was performed to obtain a yellow solid 8-methyl-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 77%. The target product has the following structural formula:

[0060]

[0061] Mp=107-108℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ8.21(d,J=8.50Hz,2H),7.97-7.95(m,2H),7.62(t,J=6.75Hz,1H),7.53-7.48(m,3H),7.44(t,J=5.75Hz4H),6.68(d,J=7.00Hz 1H),3.12(s,3H); 13 C NMR (500MHz, CDCl3): δ164.2,157.7,152.3,150.3,143.9,135.0,134.5,133.7,130. 5,130.0,128.9,128.8,128.5,128.4,125.7,118.0,24.5; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 22 H 17 N2O3357.1234, found 357.1235.

[0062] Example 5

[0063] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =7-F,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried by spin drying and column chromatography was used to obtain a yellow solid 7-fluoro-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 71%.

[0064] The target product has the following structural formula:

[0065]

[0066] Mp=112-113℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ8.94(t,J=7.50Hz,1H),8.20(d,J=8.50Hz,2H),7.94(t,J=3.75Hz,1H),7.83-7.80 (m,1H),7.70-7.63(m,2H),7.51(t,J=8.00Hz,2H),7.46(d,J=5.0Hz,2H),7.28(s,1H),4.16-4.12(m,1H); 13 CNMR (500MHz, CDCl3): δ171.2,163.9,155.0,154.1,153.4,153.1,146.0,134.9,13 3.9,130.5,128.9,128.7,128.6,128.5,128.2,128.0,127.8,113.6,113.2,89.78; 19 F NMR (400MHz, CDCl3): δ-132.4; HRMS (ESI-TOF) m / z: [M+H] + Calculate for C 21 H 14 FN2O3361.0983, found 361.0981.

[0067] Example 6

[0068] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =7-Cl,R 2 =Ph), aryl formyl peroxide (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried and column chromatography was performed to obtain a yellow oily liquid 7-chloro-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 73%. The target product has the following structural formula:

[0069]

[0070] NMR and mass spectrometry data: 1H NMR (500MHz, CDCl3): δ9.05 (d, J = 2.50Hz, 1H), 8.20 (d, J = 7.00Hz, 2H), 8.12 (d, J = 8.00Hz, 2H), 7.96 -7.94(m,2H),7.74(d,J=9.50Hz,1H),7.68-7.61(m,2H),7.52-7.49(m,1H),7.44(t,J=2.50Hz,2H); 13 CNMR (500MHz, CDCl3): δ171.2,163.9,154.3,153.1,146.3,137.5,136.7,134.8,133.9,133.6,130.5,130. 3,130.1,129.5,129.0,128.6,128.5,128.4,128.2,127.6,124.9,124.3,100.5; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 21 H 14 ClN2O3377.0687, found 377.0686.

[0071] Example 7

[0072] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =7-Br,R 2 =Ph), aryl formyl peroxide (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried by spin drying and column chromatography was used to obtain a white solid 7-bromo-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 79%.

[0073] The target product has the following structural formula:

[0074]

[0075] Mp=110-111℃; NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.15(d,J=2.50Hz,1H),8.20(d,J=8.00Hz,2H),7.95-7.93(m,2H ),7.78-7.75(m,1H),7.66-7.63(m,2H),7.51(t,J=7.75Hz,2H),7.44(t,J=3.50Hz,3H); 13C NMR (500MHz, CDCl3): δ163.9,154.2,153.0,146.4,138.7,134.9,133.9,130.5,1 30.3,129.0,128.6,128.5,127.6,127.3,110.8,100.5; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 21 H 14 BrN2O3421.0812,found421.0811.

[0076] Example 8

[0077] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =7-CF3,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried and column chromatography was performed to obtain a white solid 7-trifluoromethyl-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 69%. The target product has the following structural formula:

[0078]

[0079] Mp=99-100℃; NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.35 (s, 1H), 8.21 (d, J = 8.00Hz, 1H), 8.11 (d, J = 8.00Hz, 1H), 7.99-7.97 (m,2H),7.85-7.79(d,2H),7.66(t,J=7.50Hz,1H),7.52(t,J=7.75Hz,2H),7.48-7.46(m,3H); 13 C NMR (500MHz, CDCl3): δ163.8,154.6,153.8,147.5,134.6,134.0,133.6,130.6,130.5,130.4,13 0.1,129.1,128.8,128.6,128.5,128.4,128.0,126.8,126.7,125.8,123.6,121.5,119.4,119.1; 19 F NMR (400MHz, CDCl3): δ-63.3; HRMS (ESI-TOF) m / z: [M+H]+ Calculate for C 22 H 14 F3N2O3411.0951, found411.0950.

[0080] Example 9

[0081] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =7-CO2Et,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was spin-dried and column chromatography was performed to obtain a white solid 4-oxo-2-phenyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidine-7-carboxylic acid ethyl ester with a yield of 70%. The target product has the following structural formula:

[0082]

[0083] Mp=126-127℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.70 (d, J = 3.50Hz, 1H), 8.23-8.20 (m, 4H), 7.98 (t, J = 3.75Hz, 2H), 7.76 (d, J = 9 .00Hz,1H),7.66(t,J=7.50Hz,1H),7.54-7.46(m,6H),7.29(d,J=3.50Hz,1H),4.48(t,J=7.25Hz,2H); 13 C NMR (500MHz, CDCl3): δ163.9,163.4,154.5,153.9,148.1,134.8,134.1,133.9,131.4,130 .1,129.1,128.6,128.5,128.4,127.5,126.5,119.2,62.2,14.2; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 24 H 19 N2O5415.1288, found415.1289.

[0084] Example 10

[0085] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R2 =4-ClC6H4), aryl formyl peroxide (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410~415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was spin-dried and column chromatography was performed to obtain a white solid 2-(4-chlorophenyl)-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 84%. The target product has the following structural formula:

[0086]

[0087] Mp = 115-116 ° C; NMR and mass spectrum data: δ 9.10 (d, J = 8.5 Hz, 1H), 8.24 (d, J = 7.00 Hz, 2H), 8.10 (d, J = 8.00 Hz, 2H), 7.97-7.91 (m, 2H), 7.72 (d, J = 9.0 Hz, 1H), 7.66-7.60 (m, 2H), 7.51-7.48 (m, 1H), 7.41 (t, J = 6.50 Hz, 2H); 13 C NMR (500MHz, CDCl3): δ171.0,163.4,154.4,153.2,146.5,137.2,136.4,134.6,133.7,133.4,130. 3,130.0,129.3,129.0,128.7,128.4,128.2,127.5,124.6,124.1,100.0; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 21 H 14 ClN2O3377.0687, found 377.0685.

[0088] Embodiment 11

[0089] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =CH3), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410~415nm) at room temperature for 2h. After the reaction was completed, the mixed solution was spin-dried and column chromatography was performed to obtain a yellow solid 2-methyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 68%. The target product has the following structural formula:

[0090]

[0091] Mp=45-46℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.02 (d, J = 7.00Hz, 1H), 8.29 (d, J = 7.00Hz, 2H), 7.75 (t, J = 8.75Hz, 2H),7.68(t,J=4.75Hz,2H),7.55(t,J=8.00Hz,3H),7.28(s,1H),7.16(t,J=7.00Hz,1H); 13 C NMR (500MHz, CDCl3): δ165.3,164.0,156.6,152.7,148.0,136.3,135.3,133.9,130.5,128. 6,128.3,127.4,127.2,125.9,125.8,115.2,115.0,103.3,19.5; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 16 H 13 N2O3 281.0921, found 281.0922.

[0092] Example 12

[0093] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =6-CH3,R 2 =CH3), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 5h. After the reaction was completed, the mixed solution was spin-dried and column chromatography was performed to obtain a yellow solid 2,6-dimethyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 72%. The target product has the following structural formula:

[0094]

[0095] Mp = 86-87 ° C; NMR and mass spectrometry data are as follows: 1 H NMR (500MHz, CDCl3): δ8.89(d,J=7.50Hz,1H),8.27(d,J=8.50Hz,3H),7.65(t,J=7 .50Hz,2H),7.52(t,J=7.75Hz,4H),7.43(d,J=1.00Hz,2H),6.98(d,J=7.00Hz,2H); 13C NMR (500MHz, CDCl3): δ164.1,156.7,152.7,148.1,147.6,133.8,130.5,129.9,128 .7,128.6,128.2,127.6,126.6,123.9,118.0,21.4,19.5; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 17 H 15 N2O3295.1077, found295.1076.

[0096] Embodiment 13

[0097] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =7-CH3,R 2 =CH3), aryl peroxide compound (0.3mmol, Ar=Ph), 1mL dimethyl carbonate. The reaction was carried out under blue light (5W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried and column chromatography was performed to obtain a yellow solid 2,7-dimethyl-3-benzoyloxy-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 78%. The target product has the following structural formula:

[0098]

[0099] Mp = 110-111 °C; NMR and mass spectrometry data are as follows 1 H NMR (500MHz, CDCl3): δ8.80 (s, 2H), 8.27 (d, J = 7.00Hz, 3H), 7.65 (t, J = 7.50Hz, 2H), 7.59 (d, J = 2.00Hz, 3H), 7.52 (t, J = 7.75Hz, 4H); 13 C NMR (500MHz, CDCl3): δ164.0,156.0,152.5,147.0,138.5,133.8,130.5,129.9, 128.7,128.6,128.2,125.6,125.2,124.7,19.4,18.3; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 17 H 15 N2O3 295.1077, found 295.1075.

[0100] Embodiment 14

[0101] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=4-CH3C6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is performed to obtain a white solid 2-phenyl-3-(4-methylbenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 81%. The target product has the following structural formula:

[0102]

[0103] Mp=105-106℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.04(d,J=7.00Hz,1H),8.10(d,J=8.00Hz,2H),7.96-7.94(m,2H),7.80-7 .74(m,2H),7.44(d,J=5.50Hz,3H),7.29(t,J=7.00Hz,2H),7.18(t,J=7.00Hz,1H),2.45(s,3H); 13 C NMR (500MHz, CDCl3): δ164.1,154.5,153.9,148.0,144.7,135.3,130.6,130.0,129. 3,129.0,128.4,127.7,127.3,126.7,125.9,115.4,21.8; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 22 H 17 N2O3357.1234, found 357.1233.

[0104] Embodiment 15

[0105] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=3-CH3C6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is performed to obtain a white solid 2-phenyl-3-(3-methylbenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 76%. The target product has the following structural formula:

[0106]

[0107] Mp=151-152℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.05 (d, J = 7.00Hz, 1H), 8.02 (d, J = 9.00Hz, 2H), 7.96-7.94 (m, 2H), 7.81 -7.74(m,2H),7.44(t,J=4.00Hz,4H),7.39(t,J=7.75Hz,1H),7.20-7.17(m,1H),2.44(s,3H); 13 CNMR (500MHz, CDCl3): δ164.3,154.5,153.9,148.0,138.4,135.4,134.6,131.0,130.1, 129.0,128.6,128.4,127.8,127.7,127.3,126.7,115.4,21.3; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 22 H 17 N2O3357.1234, found 357.1231.

[0108] Example 16

[0109] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=4-OCH3C6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is used to obtain a yellow solid 2-phenyl-3-(4-methoxybenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 71%. The target product has the following structural formula:

[0110]

[0111] Mp=150-151℃;NMR and mass spectrometry data: 1 H NMR (500MHz,CDCl3): 1H NMR (500MHz, CDCl3): δ9.04(d,J=7.00Hz,1H),8.17(d,J=9.00Hz,2H),7.95-7.94(m,2H),7.79-7.73( m,2H),7.44(d,J=6.00Hz,3H),7.17(t,J=6.75Hz,1H),6.98(d,J=9.00Hz,2H),3.90(d,J=2.00Hz,3H); 13 C NMR (500MHz, CDCl3): δ164.0,163.8,154.4,154.0,148.0,135.3,132.7,130.0,129. 0,128.4,127.8,127.3,126.7,121.0,115.4,113.8,55.5; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 22 H 17 N2O4373.1183, found 373.1182.

[0112] Embodiment 17

[0113] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=4-FC6H4), 1mL dimethyl carbonate. The reaction was carried out under blue light (6W, 410-415nm) at room temperature for 3h. After the reaction was completed, the mixed solution was dried by spin drying and column chromatography was used to obtain a yellow solid 2-phenyl-3-(4-fluorobenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 74%. The target product has the following structural formula:

[0114]

[0115] Mp=103-104℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.02 (d, J=7.00Hz, 1H), 8.24-8.21 (m, 2H), 7.93 (d, J=5 .00Hz,2H),7.79-7.73(m,2H),7.45(d,J=3.00Hz,3H),7.17(t,J=8.50Hz,3H); 13C NMR (500MHz, CDCl3): δ167.3,165.2,163.1,154.5,153.8,148.1,135.5,135.2,133.2 ,133.1,130.1,128.9,128.5,127.5,127.3,126.7,125.0,124.9,115.9,115.7,115.5; 19 F NMR (400MHz, CDCl3): δ-103.8; HRMS (ESI-TOF) m / z: [M+H] + Calculate for C 21 H 14 FN2O3361.0983, found361.0982.

[0116] Embodiment 18

[0117] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=3-FC6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is used to obtain a yellow solid 2-phenyl-3-(3-fluorobenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 70%. The target product has the following structural formula:

[0118]

[0119] Mp=88-89℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.05 (d, J = 7.00Hz, 1H), 8.00 (d, J = 7.50Hz, 1H), 7.93-7.92 (m, 2H), 7. 89-7.86(m,1H),7.80-7.78(m,2H),7.50-7.45(m,4H),7.36-7.32(m,1H),7.22-7.19(m,1H); 13 CNMR (500MHz, CDCl3): δ163.5,163.0,161.5,154.6,153.7,148.1,135.6,135.1,130.8 ,130.2,128.9,128.5,127.5,127.3,126.7,126.3,121.0,120.9,117.4,117.2,115.6; 19F NMR (400MHz, CDCl3): δ-111.8; HRMS (ESI-TOF) m / z: [M+H] + Calculate for C 21 H 14 FN2O3361.0983, found 361.0985.

[0120] Embodiment 19

[0121] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=4-ClC6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is used to obtain a yellow solid 2-phenyl-3-(4-chlorobenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 72%. The target product has the following structural formula:

[0122]

[0123] Mp=120-121℃; NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.04(d,J=7.00Hz,1H),8.13(d,J=8.50Hz,2H),7.92(t ,J=3.75Hz,2H),7.80-7.74(m,2H),7.48-7.44(m,5H),7.19(t,J=6.75Hz,1H); 13 C NMR (500MHz, CDCl3): δ163.3,154.6,153.8,148.1,140.4,135.6,135.1,131.8,131.4,130. 2,129.0,128.9,128.7,128.5,127.5,127.3,127.1,126.7,115.6; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 21 H 14 ClN2O3377.0687, found377.0688.

[0124] Embodiment 20

[0125] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1=H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=2-ClC6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is performed to obtain a yellow oily liquid 2-phenyl-3-(2-chlorobenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 73%. The target product has the following structural formula:

[0126]

[0127] NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.05 (d, J = 9.00Hz, 1H), 8.06 (t, J = 5.50Hz, 1H), 7.95 (t, J = 6.00Hz, 1H), 7.91-7.89(m,2H),7.80-7.76(m,2H),7.48-7.45(m,4H),7.37-7.33(m,1H),7.20-7.17(m,1H); 13 C NMR (500MHz, CDCl3): δ169.4,162.7,154.9,153.7,148.2,135.6,135.0,134.7,134.4,133.4,133.2,132. 3,132.2,131.3,131.2,130.1,128.9,128.8,128.4,127.4,126.7,126.6,115.6; HRMS(ESI-TOF)m / z:[M+H] + calcdfor C 21 H 14 ClN2O3377.0687,found 377.0686.

[0128] Embodiment 21

[0129] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=4-BrC6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is used to obtain a yellow solid 2-phenyl-3-(4-bromobenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 78%. The target product has the following structural formula:

[0130]

[0131] Mp=119-120℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.04(d,J=7.00Hz,1H),8.06(d,J=8.50Hz,2H),7.92-7.90(m,2H ),7.81-7.75(m,2H),7.65(d,J=8.50Hz,2H),7.46-7.44(m,3H),7.20(t,J=6.50Hz,1H); 13 C NMR (500MHz, CDCl3): δ163.4,154.6,153.8,148.1,135.6,135.1,131.9,130.2,1 29.1,128.9,128.5,127.6,127.5,127.3,126.7,115.6; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 21 H 14 BrN2O3421.0182,found421.0185.

[0132] Embodiment 22

[0133] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=4-CF3C6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is used to obtain a yellow solid 2-phenyl-3-(4-trifluoromethylbenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 76%. The target product has the following structural formula:

[0134]

[0135] Mp=163-164℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.03 (d, J = 9.00Hz, 1H), 8.30 (d, J = 10.50Hz, 2H), 7.91-7 .88(m,2H),7.76(t,J=11.25Hz,4H),7.43(t,J=4.50Hz,3H),7.21-7.18(m,1H); 13C NMR (500MHz, CDCl3): δ162.9,154.7,153.7,148.2,135.7,135.0,131.9,130.8,130.2,128.8,128.5,127.4,126.8,125.6,115.7; 19 F NMR (400MHz, CDCl3): δ-63.1; HRMS (ESI-TOF) m / z: [M+H] + Calculate for C 22 H 14 F3N2O3411.0951, found411.0950.

[0136] Embodiment 23

[0137] 4H-pyrido[1,2-a]pyrimidin-4-one (0.2 mmol, R 1 =H,R 2 =Ph), aryl peroxide compound (0.3mmol, Ar=4-NO2C6H4), 1mL dimethyl carbonate. React for 3h under blue light (6W, 410~415nm) at room temperature. After the reaction is completed, the mixed solution is spin-dried and column chromatography is performed to obtain a yellow solid 2-phenyl-3-(4-nitrobenzoyloxy)-4H-pyrido[1,2-a]pyrimidin-4-one with a yield of 62%. The target product has the following structural formula:

[0138]

[0139] Mp=144-145℃;NMR and mass spectrometry data: 1 H NMR (500MHz, CDCl3): δ9.05 (d, J = 7.00Hz, 1H), 8.38-8.34 (m, 4H), 7.91-7.8 9(m,2H),7.82(d,J=5.50Hz,2H),7.46(d,J=3.75Hz,3H),7.25-7.22(m,1H); 13 C NMR (500MHz, CDCl3): δ162.3,154.7,153.6,150.9,148.3,135.9,134.9,134.1,131. 6,130.3,128.8,128.6,127.4,127.2,126.8,123.7,115.8; HRMS(ESI-TOF)m / z:[M+H] + Calculate for C 21 H 14 N3O5388.0928, found 388.0927.

[0140] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. Although the illustrative specific embodiments of the present invention are described above to facilitate the understanding of the present invention by the technical personnel in the field, it should be clear that the present invention is not limited to the scope of the specific embodiments. For the ordinary technical personnel in the field, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A C3 aromatic carboxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative, characterized in that: The structure (I) of the C3 aromatic carboxylate 4H-pyrido[1,2-a]pyrimidin-4-one derivative is as follows: R 1 =H, 6-methyl, 7-methyl, 8-methyl, 7-fluoro, 7-chloro, 7-bromo, 7-ester, 7-CF3; R 2 = methyl, phenyl, p-chlorophenyl; Ar = 2-methylphenyl, 3-methylphenyl, p-methoxyphenyl, p-fluorophenyl, 3-fluorophenyl, p-chlorophenyl, 3-chlorophenyl, p-bromophenyl, p-trifluoromethylphenyl, p-nitrophenyl.

2. A method for preparing a C3 aromatic carboxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative, characterized in that: Under room temperature and air conditions and irradiation with 410-415 nm violet light, 4H-pyrido[1,2-a]pyrimidin-4-one reacts with a peroxide aryl formyl compound in an organic solvent to prepare a C3 aryl formyloxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative.

3. The method for preparing a C3 aromatic carboxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative according to claim 2, characterized in that: The 4H-pyrido[1,2-a]pyrimidin-4-one compound is shown in the following structural formula II: Among them, R 1 =H, 6-methyl, 7-methyl, 8-methyl, 7-fluoro, 7-chloro, 7-bromo, 7-ester, 7-CF3; R 2 = methyl, phenyl, p-chlorophenyl; The aryl formyl peroxide compound is shown in the following structural formula III: Among them, Ar is 2-methylphenyl, 3-methylphenyl, p-methoxyphenyl, p-fluorophenyl, 3-fluorophenyl, p-chlorophenyl, 3-chlorophenyl, p-bromophenyl, p-trifluoromethylphenyl, or p-nitrophenyl.

4. The method for preparing a C3 aromatic carboxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative according to claim 2, characterized in that: The molar ratio of the 4H-pyrido[1,2-a]pyrimidin-4-one to the aryl formyl peroxide compound is 1:1 to 1:

2.

5. The method for preparing a C3 aromatic carboxylic acid oxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative according to claim 2, characterized in that: The organic solvent is one of ethyl acetate, dimethyl carbonate, ethanol and acetonitrile.

6. The method for preparing a C3 aromatic carboxylic acid oxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative according to claim 2, characterized in that: The concentration of the 4H-pyrido[1,2-a]pyrimidin-4-one compound in the dimethyl carbonate solvent is 0.1 mol / L to 0.5 mol / L.

7. The method for preparing a C3 aromatic carboxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative according to claim 2, characterized in that: The wavelength of the ultraviolet light source is 410-415nm, and the light intensity is 5-8W.

8. The method for preparing a C3 arylformyloxylated 4H-pyrido[1,2-a]pyrimidin-4-one derivative according to claim 2, characterized in that: The reaction temperature is room temperature, and the reaction time is 2 to 5 hours.

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