Melamine monoenamine ester derivative and preparation method thereof

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a melamine monoenamine ester derivative and a preparation method thereof. The structural general formula of the melamine monoenamine ester derivative is as shown in formula I: # imgabs0 # R is methyl, ethyl, n-propyl, n-butyl, isobutyl, tertiary butyl, n-hexyl, 1-methylheptyl, n-octyl, 3, 7-dimethyl octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl and the like. In the method, melamine and propiolic acid ester are used as raw materials, one-step synthesis is performed under the action of a catalyst and a solvent, and the method has the advantages that the operation is simple, the raw materials are cheap and easy to obtain, the yield is relatively high, the selectivity is good, the substrate adaptability is wide, the industrial production is convenient, and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a melamine monoenamine ester derivative and a preparation method thereof. Background Art

[0002] The main bottlenecks of melamine formaldehyde resin are its brittleness and single performance. The fundamental reason is that the three amine groups in the melamine molecule have the same activity and the network structure formed by the reaction with formaldehyde is too rigid. The current solution is mainly to modify melamine formaldehyde resin by polymer modification to achieve toughening. Although good results have been achieved, the polymer modification method does not change the basic structure of melamine formaldehyde resin and does not solve the problems faced by melamine resin from the root.

[0003] The manifestation of polymer mechanical properties is fundamentally determined by its structural units. To obtain polymers with various properties, in addition to the polymerization method and process that affect its macromolecular structure, the functional monomer is the key to giving the polymer special properties. In view of the problems faced by melamine formaldehyde resin, we intend to adjust the polymer molecular network at the molecular level and develop a class of functional monomer molecules with melamine monosubstituted characteristics in a targeted manner. This functional molecule is a pseudo-melamine molecule with a single amine substitution directly synthesized by chemical synthesis on an amine group in the melamine molecule. When it is added to the melamine, formaldehyde and other systems, copolymerization occurs. Through the steric hindrance effect of the functional monomer in the polymer chain and the inability to form a complete network, the microscopic network morphology of the melamine formaldehyde resin is fundamentally improved, thereby solving the problem of excessive rigidity of the melamine formaldehyde resin.

[0004] The existing methods for synthesizing monofunctionalized melamine derivatives mainly include the following: (1) Using melamine and alkyl halides as raw materials, the construction of monofunctionalized melamine derivatives is achieved through Hofmann alkylation reaction ((a) CN113788801, 2021, A). The disadvantage of this method is that the substrate type is single, the reaction selectivity is poor, it is difficult to achieve selective monofunctionalization of melamine, and the product is mostly a mixture of monofunctionalized, difunctionalized and trifunctionalized. (2) Synthesizing monofunctionalized melamine derivatives through condensation reaction of melamine with alcohols and amines ((b) Adv. Mater. Res. 2012, 450-451, 68-73; (c) CN110256367, 2019, A). The disadvantage of this method is that the reaction conditions are harsh, involving strong acid, strong base, high temperature and other reaction conditions. (3) Using cyanuric chloride and primary / secondary amine as raw materials, monofunctionalized melamine derivatives are directly obtained through a two-step reaction ((d) J. Org. Chem. 2016, 81, 4066). This method has low atom economy and is not conducive to industrial production. In summary, it is of great significance to develop new methods for selectively constructing monofunctionalized melamine derivatives using melamine as raw material. Summary of the invention

[0005] The technical problem solved by the invention is to realize the selective monofunctionalization reaction of melamine and propiolate compounds under mild reaction conditions to synthesize a series of novel melamine monoenamine ester derivatives.

[0006] In view of the above technical problems, the technical solution adopted by the present invention is to provide a melamine monoenamine ester derivative and a preparation method thereof.

[0007] Specifically:

[0008] First, the present invention provides a melamine monoenamine ester derivative, the general structural formula of the melamine monoenamine ester derivative is shown in Formula I:

[0009]

[0010] In Formula I,

[0011] R is methyl, ethyl, n-propyl, n-butyl, isobutyl, tert-butyl, n-hexyl, 1-methylheptyl, n-octyl, 3,7-dimethyloctyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, cyclopropylmethyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclododecyl, 4-pentenyl, 4-hexenyl, 5-hexenyl, 9-decenyl, 10-carbon undecenyl, 3-cyclopentenylmethyl, 3-cyclohexenylmethyl, 4-pentynyl, 5-hexynyl, 6-heptynyl, 3-nitrilepropyl, 2-(2-methylallyloxy)ethyl, 3-phenylpropyl.

[0012] Second, the present invention provides a method for preparing a melamine monoenamine ester derivative, comprising the following steps:

[0013] Melamine and propiolate are added into a reaction container, and then a catalyst and a solvent are added, and melamine monoenamine ester derivatives are obtained through reaction, separation and purification.

[0014] Furthermore, the chemical reaction formula of the preparation method of the melamine monoenamine ester derivative is:

[0015]

[0016] Preferably, in the method for preparing the melamine monoenamine ester derivatives, the molar ratio of melamine to propiolate is 1:1.05 to 1:5.

[0017] Preferably, in the method for preparing the melamine monoenamine ester derivatives, the molar ratio of melamine to catalyst is 1:0.05 to 1:0.3.

[0018] Preferably, in the preparation method of the melamine monoenamine ester derivatives, the catalyst includes at least one of HCl, TsOH, B(C5F6)3, Fe(acac)3, Cu(OTf)2, Fe(OTf)3, Ni(OTf)3, BiCl3, ZnCl2, AlCl3, H2SO4, HI, and HNO3.

[0019] Preferably, in the method for preparing the melamine monoenamine ester derivatives, the solvent includes at least one of EtOH, H2O, THF, (CH2OH)2, MeCN, DMF, DCE, and DMSO.

[0020] Preferably, in the method for preparing the melamine monoenamine ester derivatives, the amount of solvent added is suitable for dissolving melamine, such as melamine: solvent = 126.1 mg: 2 mL.

[0021] Preferably, in the method for preparing the melamine monoenamine ester derivatives, the reaction temperature is 50° C. to 120° C., and the reaction time is 6 to 24 hours.

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

[0023] (1) The novel melamine monoenamine ester derivatives provided by the present invention are a class of compounds with a completely new structure and have the potential to be used as a functional monomer molecule in the field of materials science;

[0024] (2) The synthesis method provided by the present invention uses melamine and propiolate as raw materials and is synthesized in one step under the action of a catalyst and a solvent. It has the advantages of simple operation, low cost, high yield, good selectivity, wide substrate adaptability, and convenience for industrial production. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is clearly and completely described in conjunction with the embodiments below. All features disclosed in this specification, or steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way. Any feature disclosed in this specification (including claims), unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes. That is, unless otherwise stated, each feature is just an example of a series of equivalent or similar features.

[0026] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0027] Embodiment 1:

[0028] Synthesis of melamine monoenamine ester derivatives 3.1

[0029]

[0030] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of tetrahydrofuran. Then 126.1 mg of methyl propiolate and 40.3 mg of aluminum chloride were added in sequence. The reaction was carried out at 60°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with acetone, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.1, with a yield of 76%.

[0031] Melamine monoenamine ester derivative 3.1, white solid, melting point: 251-252℃. 1 H NMR (400MHz, DMSO-d6) δ9.80(d,J=11.9Hz,1H),8.29(dd,J=13.9,11.9Hz,1H),6.57(s,4H),5.34(d,J=13.9Hz,1H),3.59(s,3H). 13 C NMR(101MHz,DMSO-d6)δ168.4,167.7,164.0,142.0,95.1,51.0.HRMS(ESI):m / z:[M+H] + Calcd.for C7H 11 N6O2 +:211.0938;Found:211.0948.

[0032] Embodiment 2:

[0033] Synthesis of melamine monoenamine ester derivatives 3.2

[0034]

[0035] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of tetrahydrofuran. Then 147.2 mg of ethyl propiolate and 40.3 mg of aluminum chloride were added in sequence. The reaction was carried out at 60°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with acetone, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.2, with a yield of 72%.

[0036] Melamine monoenamine ester derivative 3.2, white solid, melting point: 208-209℃. 1 H NMR (400MHz, DMSO-d6) δ9.79(d,J=11.9Hz,1H),8.29–8.22(m,1H),6.57(s,4H),5.33(d,J=13.9Hz,1H),4.06(q,J=7.1Hz,2H),1.18(t,J=7.1Hz,3H). 13 CNMR(101MHz,DMSO-d6)δ168.0,167.7,164.0,141.8,95.6,59.3,14.9.HRMS(ESI):m / z:[M+H] + Calcd.for C8H 13 N6O2 + :225.1100;Found:225.1102.

[0037] Embodiment 3:

[0038] Synthesis of melamine monoenamine ester derivatives 3.3

[0039]

[0040] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of tetrahydrofuran. Then 168.2 mg of n-propyl propiolate and 40.3 mg of aluminum chloride were added in sequence. The reaction was carried out at 60°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered off, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.3, with a yield of 74%.

[0041] Melamine monoenamine ester derivative 3.3, white solid, melting point: 205-206℃.1 H NMR(400MHz,DMSO-d6)δ9.80(d,J=11.9Hz,1H),8.26(dd,J=13.9,11.9Hz,1H),6.56(s,4H), 5.34(d,J=13.9Hz,1H), 3.97(t,J=6.7Hz,2H), 1.58(h,J=7.2Hz,2H), 0.89(t,J=7.4Hz,3H). 13 CNMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.8,95.5,64.9,22.3,10.8.HRMS(ESI):m / z:[M+H] + Calcd.for C9H 15 N6O2 + :239.1256;Found:239.1260.

[0042] Embodiment 4:

[0043] Synthesis of melamine monoenamine ester derivatives 3.4

[0044]

[0045] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of water. Then 378.5 mg of n-butyl propiolate and 54.3 mg of trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80 ° C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with acetone, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.4, with a yield of 73%.

[0046] Melamine monoenamine ester derivative 3.4, white solid, melting point: 203-204℃. 1 H NMR(400MHz, DMSO-d6)δ9.81(d,J=11.9Hz,1H),8.27(dd,J=13.9,11.9Hz,1H),6.58(s,4H),5.35(d,J=13 .9Hz,1H),4.03(t,J=6.7Hz,2H),1.59–1.52(m,2H),1.33(dq,J=14.5,7.3Hz,2H),0.90(t,J=7.4Hz,3H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.8,167.7,164.0,141.8,95.6,63.1,31.0,19.2,14.1.HRMS(ESI):m / z:[M+H] + Calcd.for C10 H 17 N6O2 + :253.1413;Found:253.1417.

[0047] Embodiment 5:

[0048] Synthesis of melamine monoenamine ester derivatives 3.5

[0049]

[0050] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of tetrahydrofuran, followed by the addition of 378.5 mg of isobutyl propiolate and 2 drops of hydrochloric acid. The mixture was reacted at 60 °C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered off, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.5, with a yield of 74%.

[0051] Melamine monoenamine ester derivative 3.5, white solid, melting point: 202-203℃. 1 H NMR(400MHz,DMSO-d6)δ9.81(d,J=11.9Hz,1H),8.28(dd,J=13.8,11.9Hz,1H),6.57(s,4H),5.3 6(d,J=13.9Hz,1H),3.82(d,J=6.7Hz,2H),1.87(m,J=6.6,6.0Hz,1H),0.90(s,3H),0.88(s,3H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,95.5,69.3,27.9,19.4.HRMS(ESI):m / z:[M+H] + Calcd.for C 10 H 17 N6O2 + :253.1413;Found:253.1418.

[0052] Embodiment 6:

[0053] Synthesis of melamine monoenamine ester derivatives 3.6

[0054]

[0055] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of acetonitrile. Then 378.5 mg of tert-butyl propiolate and 106.0 mg of ferric acetylacetonate were added in sequence. The reaction was carried out at 60 ° C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with acetone, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.6, with a yield of 72%.

[0056] Melamine monoenamine ester derivative 3.6, white solid, melting point: 201-202℃. 1 H NMR (400MHz, DMSO-d6) δ9.71(d,J=11.8Hz,1H),8.17(dd,J=13.8,11.9Hz,1H),6.55(s,4H),5.26(d,J=13.8Hz,1H),1.42(s,9H). 13 C NMR(101MHz,DMSO-d6)δ167.7,167.6,164.0,141.1,97.5,78.8,28.5.HRMS(ESI):m / z:[M+H] + Calcd.for C 10 H 17 N6O2 + :253.1413;Found:253.1424.

[0057] Embodiment 7:

[0058] Synthesis of melamine monoenamine ester derivatives 3.7

[0059]

[0060] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of acetonitrile. Then 231.3 mg of n-hexyl propiolate and 2 drops of nitric acid were added in sequence. The reaction was carried out at 60 °C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.7, with a yield of 74%.

[0061] Melamine monoenamine ester derivative 3.7, white solid, melting point: 196-197℃. 1 H NMR(400MHz, DMSO-d6)δ9.82(d,J=11.9Hz,1H),8.28(dd,J=13.9,11.9Hz,1H),6.59(s,4H),5.35( d,J=13.9Hz,1H),4.02(t,J=6.7Hz,2H),1.60–1.54(m,2H),1.30–1.24(m,6H),0.88–0.85(m,3H).13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.8,95.6,63.4,31.4,28.9,25.6,22.5,14.3.HRMS(ESI):m / z:

[0062] [M+H] + Calcd.for C 12 H 21 N6O2 + :281.1726;Found:281.1736.

[0063] Embodiment 8:

[0064] Synthesis of melamine monoenamine ester derivatives 3.8

[0065]

[0066] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of acetonitrile. Then 273.4 mg of 1-methylheptyl propiolate and 2 drops of concentrated sulfuric acid were added in sequence. The reaction was carried out at 60°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.8, with a yield of 68%.

[0067] Melamine monoenamine ester derivatives 3.8, white solid, melting point: 189-190℃. 1 H NMR(400MHz, DMSO-d6)δ9.78(d,J=11.9Hz,1H),8.23(dd,J=13.9,11.9Hz,1H),6.57(s,4H),5.31(d,J=13.9H z,1H),4.82(h,J=6.3Hz,1H),1.52–1.41(m,2H),1.27–1.19(m,8H),1.13(d,J=6.3Hz,3H),0.86–0.80(m,3H). 13 C NMR(101MHz,DMSO-d6)δ167.8,167.6,164.0,141.6,96.1,69.3,36.0,31.6,29.0,25.4,22.5,20.5,14.3.HRMS(ESI):m / z:[M+H] + Calcd.forC 14 H 25 N6O2 + :309.2039;Found:309.2050.

[0068] Embodiment 9:

[0069] Synthesis of melamine monoenamine ester derivatives 3.9

[0070]

[0071] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of ethanol. Then 273.4 mg of n-octyl propiolate and 47.3 mg of bismuth chloride were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.9, with a yield of 74%.

[0072] Melamine monoenamine ester derivative 3.9, white solid, melting point: 191-192℃. 1 H NMR (400MHz, DMSO-d6) δ9.80 (d, J=11.9Hz, 1H), 8.26 (dd, J=13.9, 11.9Hz, 1H), 6.56 (s, 4H), 5.33 (d, J=13.9Hz,1H),4.01(t,J=6.7Hz,2H),1.56(p,J=6.7Hz,2H),1.31–1.23(m,10H),0.88–0.83(m,3H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.8,95.5,63.4,31.7,29.13,29.08,28.9,25.9,22.5,14.4.HRMS(ESI):m / z:[M+H] + Calcd.for C 14 H 25 N6O2 + :309.2039;Found:309.2039.

[0073] Embodiment 10:

[0074] Synthesis of melamine monoenamine ester derivatives 3.10

[0075]

[0076] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of dimethyl sulfoxide. Then 315.5 mg of 3,7-dimethyloctyl propiolate and 150.9 mg of iron trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80° C. for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.10, with a yield of 60%.

[0077] Melamine monoenamine ester derivative 3.10, white solid, melting point: 184-185℃. 1 H NMR(400MHz,DMSO-d6)δ9.79(d,J=11.9Hz,1H),8.25(dd,J=13.9,12.0Hz,1H ),6.55(s,4H),5.32(d,J=13.9Hz,1H),4.05(tq,J=8.1,4.2Hz,2H),1.59(dd ,J=12.9,5.6Hz,1H),1.53–1.47(m,2H),1.38(dd,J=13.5,6.7Hz,1H),1.29– 1.25(m,2H),1.19–1.07(m,4H),0.87(d,J=6.5Hz,3H),0.84(d,J=6.6Hz,6H). 13 CNMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,95.5,61.7,37.0,35.8,29.8,27.8,24.5,23.0,22.9,19.9.HRMS(ESI):m / z:[M+H] + Calcd.for C 16 H 29 N6O2 + :337.2352;Found:337.2366.

[0078] Embodiment 11:

[0079] Synthesis of melamine monoenamine ester derivatives 3.11

[0080]

[0081] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of 1,2-dichloroethane. Then 315.5 mg of n-decyl propiolate and 20.4 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with acetone, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.11, with a yield of 75%.

[0082] Melamine monoenamine ester derivative 3.11, white solid, melting point: 187-188℃. 1H NMR (400MHz, DMSO-d6) δ9.81(d,J=11.8Hz,1H),8.25(t,J=12.8Hz,1H),6.57(s,4H),5.31(d,J=13. 9Hz,1H),3.99(t,J=6.7Hz,2H),1.58–1.51(m,2H),1.25(d,J=15.7Hz,14H),0.84(t,J=6.5Hz,3H). 13 C NMR (101 MHz, DMSO-d6)δ

[0083] 168.0,167.6,163.9,141.8,95.4,63.3,31.7,29.4,29.1,28.9,25.9,22.5,14.4.HRMS(ESI):m / z:[M+H] + Calcd.for C 16 H 29 N6O2 + :337.2352;Found:337.2357.

[0084] Embodiment 12:

[0085] Synthesis of melamine monoenamine ester derivatives 3.12

[0086]

[0087] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of acetonitrile. Then 357.6 mg of n-dodecyl propiolate and 2 drops of hydroiodic acid were added in sequence. The reaction was carried out at 60 °C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.12, with a yield of 74%.

[0088] Melamine monoenamine ester derivative 3.12, white solid, melting point: 182-183℃. 1 H NMR (400MHz, DMSO-d6) δ9.80 (d, J=11.9Hz, 1H), 8.26 (dd, J=13.9, 11.9Hz, 1H), 6.56 (s, 4H), 5.33 (d, J= 13.9Hz,1H),4.00(t,J=6.8Hz,2H),1.56(t,J=6.8Hz,2H),1.25(d,J=11.5Hz,18H),0.87–0.83(m,3H). 13C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.8,95.5,63.3,31.8,29.52,29 .49,29.46,29.42,29.20,29.17,28.9,25.9,22.6,14.4.HRMS(ESI):m / z:[M+H] + Calcd.for C 18 H 33 N6O2 + :365.2665;Found:365.2667.

[0089] Embodiment 13:

[0090] Synthesis of melamine monoenamine ester derivative 3.13

[0091]

[0092] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of tetrahydrofuran, and then 399.6 mg of tetradecyl propiolate and 72.3 mg of trifluoromethanesulfonate were added in sequence. The reaction was carried out at 60°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.13, with a yield of 76%.

[0093] Melamine monoenamine ester derivative 3.13, white solid, melting point: 178-179℃. 1 H NMR(400MHz,DMSO-d6)δ9.80(d,J=11.9Hz,1H),8.26(dd,J=13.9,11.9Hz,1H),6.55(s,4H),5.3 3(d,J=13.9Hz,1H),4.00(t,J=6.8Hz,2H),1.58–1.53(m,2H),1.23(s,22H),0.87–0.83(m,3H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.8,95.5,63.3,31.8,29.54,29.53 ,29.50,29.46,29.43,29.20,29.17,28.9,25.9,22.6,14.4.HRMS(ESI):m / z:[M+H] + Calcd.for C 20 H 37 N6O2 + :393.2978;Found:393.2980.

[0094] Embodiment 14:

[0095] Synthesis of melamine monoenamine ester derivative 3.14

[0096]

[0097] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of 1,2-dichloroethane. Then 441.7 mg of hexadecyl propiolate and 20.4 mg of zinc chloride were added in sequence. The mixture was reacted at 80°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.14, with a yield of 78%.

[0098] Melamine monoenamine ester derivative 3.14, white solid, melting point: 174-175℃. 1 H NMR (400MHz, DMSO-d6) δ9.79 (d, J=11.9Hz, 1H), 8.30–8.21 (m, 1H), 6.55 (s, 4H), 5.32 (d, J= 13.9Hz,1H),4.00(t,J=6.7Hz,2H),1.55(t,J=6.9Hz,2H),1.23(s,26H),0.86–0.83(m,3H). 13 CNMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.8,95.5,63.3,31.8,29.52,2 9.49,29.45,29.42,29.19,29.17,28.9,25.9,22.6,14.4.HRMS(ESI):m / z:[M+H] + Calcd.for C 22 H 41 N6O2 + :421.3291;Found:421.3293.

[0099] Embodiment 15:

[0100] Synthesis of melamine monoenamine ester derivative 3.15

[0101]

[0102] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of ethylene glycol. Then 496.6 mg of cyclopropylmethyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.15, with a yield of 48%.

[0103] Melamine monoenamine ester derivative 3.15, white solid, melting point: 193-194℃. 1 H NMR (400MHz, DMSO-d6) δ9.80(d,J=11.9Hz,1H),8.26(dd,J=13.9,11.8Hz,1H),6.56(s,4H),5.35(d,J=13. 9Hz,1H),3.85(d,J=7.2Hz,2H),1.07(ddd,J=12.5,7.7,4.8Hz,1H),0.51–0.47(m,2H),0.26–0.22(m,2H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,95.6,67.9,10.5,3.5.HRMS(ESI):m / z:[M+H] + Calcd.for C 10 H 15 N6O2 + :251.1256;Found:251.1259.

[0104] Embodiment 16:

[0105] Synthesis of melamine monoenamine ester derivative 3.16

[0106]

[0107] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of ethylene glycol. Then 496.6 mg of cyclobutyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.16, with a yield of 54%.

[0108] Melamine monoenamine ester derivative 3.16, white solid, melting point: 189-190℃. 1H NMR(400MHz, DMSO-d6)δ9.83(d,J=11.9Hz,1H),8.26(dd,J=13.9,11.9Hz,1H),6.59(s,4H),5.32(d,J=13.8 Hz,1H),4.97–4.91(m,1H),2.29–2.24(m,2H),2.02–1.96(m,2H),1.73(d,J=10.1Hz,1H),1.61–1.56(m,1H). 13 C NMR(101MHz,DMSO-d6)δ167.7,167.4,164.0,141.9,95.5,67.5,30.6,20.9,13.6.HRMS(ESI):m / z:[M+H] + Calcd.for C 10 H 15 N6O2 + :251.1256;Found:251.1259.

[0109] Embodiment 17:

[0110] Synthesis of melamine monoenamine ester derivative 3.17

[0111]

[0112] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of ethylene glycol. Then 552.7 mg of cyclopentyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.17, with a yield of 64%.

[0113] Melamine monoenamine ester derivative 3.17, white solid, melting point: 181-182℃. 1 H NMR (400MHz, DMSO-d6) δ9.80 (d, J=11.9Hz, 1H), 8.25 (dd, J=13.9, 11.8Hz, 1H), 6.59 (s, 4H), 5.32 (d, J=13.9Hz,1H),5.09(tt,J=5.9,2.9Hz,1H),1.87–1.79(m,2H),1.69–1.63(m,2H),1.62–1.53(m,4H). 13 C NMR(101MHz,DMSO-d6)δ167.9,167.7,164.0,141.6,96.1,75.6,32.8,23.8.HRMS(ESI):m / z:[M+H]+ Calcd.for C 11 H 17 N6O2 + :265.1413;Found:265.1417.

[0114] Embodiment 18:

[0115] Synthesis of melamine monoenamine ester derivative 3.18

[0116]

[0117] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of ethylene glycol. Then 608.8 mg of cyclohexyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.18, with a yield of 68%.

[0118] Melamine monoenamine ester derivative 3.18, white solid, melting point: 178-179℃. 1 H NMR (400MHz, DMSO-d6) δ9.78(d,J=11.9Hz,1H),8.24(dd,J=13.9,11.9Hz,1H),6.56(s,4H),5.32(d,J=13.9Hz,1H),4.66(p ,J=4.9Hz,1H),1.80(dd,J=9.3,4.4Hz,2H),1.70–1.65(m,2H),1.50(d,J=7.9Hz,1H),1.37–1.30(m,4H),1.24–1.17(m,1H). 13 C NMR(101MHz,DMSO-d6)δ167.7,167.5,164.0,141.7,96.0,71.2,32.0,25.4,23.9.HRMS(ESI):m / z:[M+H] + Calcd.for C 12 H 19 N6O2 + :279.1569;Found:279.1573.

[0119] Embodiment 19:

[0120] Synthesis of melamine monoenamine ester derivative 3.19

[0121]

[0122] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of ethylene glycol. Then 664.9 mg of cycloheptyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.19, with a yield of 54%.

[0123] Melamine monoenamine ester derivative 3.19, white solid, melting point: 161-162℃. 1 H NMR(400MHz,DMSO-d6)δ9.80(d,J=11.7Hz,1H),8.25(dd,J=13.8,11.6Hz,1H),6.57(s,4H), 5.35(d,J=13.9Hz,1H),4.85(tt,J=8.3,4.4Hz,1H),1.89–1.80(m,2H),1.65–1.40(m,10H). 13 C NMR(101MHz,DMSO-d6)δ167.6,167.5,164.0,141.5,96.3,73.7,39.1,34.0,28.2,22.8.HRMS(ESI):m / z:[M+H] + Calcd.for C 13 H 21 N6O2 + :293.1726;Found:293.1737.

[0124] Embodiment 20:

[0125] Synthesis of melamine monoenamine ester derivatives 3.20

[0126]

[0127] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of ethylene glycol. Then 945.4 mg of cyclododecyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 12 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.20, with a yield of 64%.

[0128] Melamine monoenamine ester derivative 3.20, white solid, melting point: 154-155℃. 1H NMR(400MHz,DMSO-d6)δ9.79(d,J=11.8Hz,1H),8.25(dd,J=13.9,11.9Hz,1H),6.57(s,4H), 5.32(d,J=13.9Hz,1H),4.99–4.93(m,1H),1.69–1.62(m,2H),1.39(dd,J=51.2,5.6Hz,20H). 13 CNMR(101MHz,DMSO-d6)δ167.8,167.7,164.0,141.6,96.0,70.1,29.5,24.0,23.8,23.5,23.2,21.1.HRMS(ESI):m / z:

[0129] [M+H] + Calcd.for C 18 H 31 N6O2 + :363.2508;Found:363.217.

[0130] Embodiment 21:

[0131] Synthesis of melamine monoenamine ester derivative 3.21

[0132]

[0133] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of N,N-dimethylformamide, and then 414.5 mg of 4-pentenyl propiolate and 71.4 mg of nickel trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with methanol, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.21, with a yield of 74%.

[0134] Melamine monoenamine ester derivative 3.21, white solid, melting point: 173-174℃. 1 H NMR(400MHz, DMSO-d6)δ9.80(d,J=11.9Hz,1H),8.27(dd,J=13.9,11.9Hz,1H),6.56(s,4H),5.85–5.78(m,1H ),5.34(d,J=13.9Hz,1H),5.06–4.96(m,2H),4.02(t,J=6.8Hz,2H),2.07(d,J=6.3Hz,2H),1.69–1.64(m,2H). 13C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,138.3,115.7,95.5,62.8,30.1,28.1.HRMS(ESI):m / z:[M+H] + Calcd.for C 11 H 17 N6O2 + :265.1413;Found:265.1417.

[0135] Embodiment 22:

[0136] Synthesis of melamine monoenamine ester derivative 3.22

[0137]

[0138] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of N,N-dimethylformamide, and then 456.6 mg of 4-hexenyl propiolate and 71.4 mg of nickel trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.22, with a yield of 72%.

[0139] Melamine monoenamine ester derivative 3.22, white solid, melting point: 174-175℃. 1 H NMR(400MHz,DMSO-d6)δ9.79(d,J=11.9Hz,1H),8.26(dd,J=13.9,11.9Hz,1H),6.55(s,4H),5.43– 5.40(m,2H),5.34(d,J=13.9Hz,1H),4.00(t,J=6.7Hz,2H),2.02–1.97(m,2H),1.63–1.58(m,5H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,130.8,125.5,95.5,62.9,28.9,28.8,18.2.HRMS(ESI):m / z:[M+H] + Calcd.for C 12 H 19 N6O2 + :279.1569;Found:279.1573.

[0140] Embodiment 23:

[0141] Synthesis of melamine monoenamine ester derivative 3.23

[0142]

[0143] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of N,N-dimethylformamide, and then 456.6 mg of 5-hexenyl propiolate and 71.4 mg of nickel trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid melamine monoenamine ester derivative 3.23 with a yield of 80%.

[0144] Melamine monoenamine ester derivative 3.23, white solid, melting point: 176-177℃. 1 H NMR (400MHz, DMSO-d6) δ9.77(d,J=11.9Hz,1H),8.26(dd,J=13.9,11.9Hz,1H),6.53(s,4H),5.83–5.76(m,1H),5.34(d,J =13.9Hz,1H),5.04–4.94(m,2H),4.02(t,J=6.7Hz,2H),2.05(q,J=6.3,5.5Hz,2H),1.60–1.55(m,2H),1.42–1.37(m,2H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,138.9,115.4,95.5,63.2,33.2,28.4,25.2.HRMS(ESI):m / z:[M+H] + Calcd.for C 12 H 19 N6O2 + :279.1569;Found:279.1573.

[0145] Embodiment 24:

[0146] Synthesis of melamine monoenamine ester derivative 3.24

[0147]

[0148] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of N,N-dimethylformamide, and then 624.9 mg of 9-decenyl propiolate and 71.4 mg of nickel trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with methanol, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.24, with a yield of 81%.

[0149] Melamine monoenamine ester derivative 3.24, white solid, melting point: 180-181℃. 1 H NMR(400MHz, DMSO-d6)δ9.82(d,J=11.9Hz,1H),8.28(dd,J=13.9,11.9Hz,1H),6.59(s,4H),5.82–5.75(m,1H),5.34(d,J =13.9Hz,1H),5.01–4.91(m,2H),4.01(t,J=6.8Hz,2H),2.00(q,J=6.6Hz,2H),1.56(p,J=7.2,6.4Hz,2H),1.27(s,10H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.8,139.3,115.1,95.6,63.3,33.6,29.2,29.1,28.9,28.7,25.9.HRMS(ESI):m / z:[M+H] +

[0150] Calcd.for C 16 H 27 N6O2 + :335.2195;Found:335.2203.

[0151] Embodiment 25:

[0152] Synthesis of melamine monoenamine ester derivative 3.25

[0153]

[0154] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of N,N-dimethylformamide, and then 667.0 mg of 10-undecenyl propiolate and 71.4 mg of nickel trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with methanol, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.25, with a yield of 76%.

[0155] Melamine monoenamine ester derivatives 3.25, white solid, melting point: 188-189℃. 1H NMR(400MHz, DMSO-d6)δ9.79(d,J=11.9Hz,1H),8.26(dd,J=13.9,11.9Hz,1H),6.55(s,4H),5.82–5.75(m,1H),5.33(d,J=13.9Hz,1H),4.99( dd,J=17.1,1.9Hz,1H),4.93(dd,J=10.2,2.0Hz,1H),4.00(t,J=6.7Hz,2H),2.03–1.98(m,2H),1.56(t,J=6.9Hz,2H),1.26(d,J=5.7Hz,12H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.8,139.3,115.1,95.6,63.4, 39.3,33.6,29.3,29.2,29.1,28.93,28.89,28.7,25.9.HRMS(ESI):m / z:[M+H] + Calcd.forC 17 H 29 N6O2 + :349.2352;Found:349.2356.

[0156] Embodiment 26:

[0157] Synthesis of melamine monoenamine ester derivative 3.26

[0158]

[0159] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of N,N-dimethylformamide, and then 750.9 mg of propiolic acid-(3-cyclopentenyl)methyl ester and 71.4 mg of nickel trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.26, with a yield of 72%.

[0160] Melamine monoenamine ester derivative 3.26, white solid, melting point: 179-180℃. 1H NMR(400MHz,DMSO-d6)δ9.79(d,J=11.9Hz,1H),8.27(dd,J=13.9,11.9Hz,1H),6.54(s,4H),5.68(s,2H), 5.35(d,J=13.9Hz,1H), 3.94(d,J=7.2Hz,2H), 2.43(dd,J=14.5,8.1Hz,2H), 2.06(dd,J=13.8,5.2Hz,2H). 13 C NMR(101MHz,DMSO-d6)δ168.2,167.7,164.0,142.0,129.9,95.4,67.0,36.2,35.9.HRMS(ESI):m / z:[M+H] + Calcd.for C 12 H 17 N6O2 + :277.1413;Found:277.1417.

[0161] Embodiment 27:

[0162] Synthesis of melamine monoenamine ester derivative 3.27

[0163]

[0164] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of N,N-dimethylformamide, and then 821.0 mg of methyl (3-cyclohexenyl) propiolate and 71.4 mg of nickel trifluoromethanesulfonate were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.27, with a yield of 70%.

[0165] Melamine monoenamine ester derivatives 3.27, white solid, melting point: 170-171℃. 1 H NMR(400MHz, DMSO-d6)δ9.79(d,J=11.9Hz,1H),8.27(dd,J=13.9,11.9Hz,1H),6.53(s,4H),5.65(s,2H),5.35(d, J=13.9Hz,1H),3.93(d,J=6.7Hz,2H),2.03–2.01(m,2H),1.89–1.84(m,1H),1.76–1.71(m,2H),1.28–1.23(m,1H). 13CNMR(101MHz,DMSO-d6)δ167.1,166.7,162.9,140.9,126.2,125.0,94.3,66.4,32.2,27.1,24.3,23.3.HRMS(ESI):m / z:[M+H] + Calcd.forC 13 H 19 N6O2 + :291.1569;Found:291.1574.

[0166] Embodiment 28:

[0167] Synthesis of melamine monoenamine ester derivatives 3.28

[0168]

[0169] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of 1,2-dichloroethane, and then 143.0 mg of 4-pentynyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with methanol, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.28, with a yield of 66%.

[0170] Melamine monoenamine ester derivatives 3.28, white solid, melting point: 167-168℃. 1 H NMR (400MHz, DMSO-d6) δ9.82(d,J=11.9Hz,1H),8.27(dd,J=13.8,11.8Hz,1H),6.55(s,4H),5.35(d,J=13. 8Hz, 1H), 4.08 (t, J = 6.5Hz, 2H), 2.79 (t, J = 2.7Hz, 1H), 2.24 (td, J = 6.9, 2.6Hz, 2H), 1.76 (p, J = 6.7Hz, 2H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,142.0,95.3,84.0,72.0,62.2,49.1,27.8,15.0.HRMS(ESI):m / z:[M+H] + Calcd.for C 11 H 15 N6O2 + :263.1256;Found:263.1260.

[0171] Embodiment 29:

[0172] Synthesis of melamine monoenamine ester derivatives 3.29

[0173]

[0174] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of 1,2-dichloroethane, and then 157.7 mg of 5-hexynyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with methanol, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.29, with a yield of 66%.

[0175] Melamine monoenamine ester derivative 3.29, white solid, melting point: 169-170℃. 1 H NMR(400MHz,DMSO-d6)δ9.81(d,J=11.9Hz,1H),8.27(dd,J=13.9,11.9Hz,1H),6.56(s,4H),5.35(d,J=13.9Hz,1H),4.04 (t,J=6.6Hz,2H),2.75(t,J=2.7Hz,1H),2.20(td,J=7.0,2.7Hz,2H),1.67(dt,J=14.3,6.6Hz,2H),1.49(p,J=7.0Hz,2H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,95.5,84.7,71.8,62.9,49.1,28.1,25.0,17.8.HRMS(ESI):m / z:[M+H] + Calcd.for C 12 H 17 N6O2 + :277.1413;Found:277.1416.

[0176] Embodiment 30:

[0177] Synthesis of melamine monoenamine ester derivatives 3.30

[0178]

[0179] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of 1,2-dichloroethane, and then 172.4 mg of 6-heptyl propiolate and 40.9 mg of zinc chloride were added in sequence. The reaction was carried out at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with methanol, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.30, with a yield of 52%.

[0180] Melamine monoenamine ester derivative 3.30, white solid, melting point: 172-173℃. 1 H NMR (400MHz, DMSO-d6) δ9.81(d,J=11.9Hz,1H),8.27(dd,J=13.9,11.9Hz,1H),6.58(s,4H),5.34(d,J=13.8Hz,1H),4.02(t,J=6.7H z,2H),2.73(t,J=2.7Hz,1H),2.17(td,J=6.9,2.7Hz,2H),1.58(p,J=6.8Hz,2H),1.47(t,J=6.8Hz,2H),1.40(q,J=4.9,4.4Hz,2H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,95.5,84.9,71.6,63.2,28.4,28.1,25.1,18.1.HRMS(ESI):m / z:[M+H] +

[0181] Calcd.for C 13 H 19 N6O2 + :291.1569;Found:291.1565.

[0182] Embodiment 31:

[0183] Synthesis of melamine monoenamine ester derivative 3.31

[0184]

[0185] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of 1,2-dichloroethane, and then 129.3 mg of 3-cyanopropyl propiolate and 40.9 mg of zinc chloride were added in sequence. The mixture was reacted at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with PE:EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.31, with a yield of 80%.

[0186] Melamine monoenamine ester derivative 3.31, white solid, melting point: 213-214℃. 1H NMR(400MHz,DMSO-d6)δ9.92(d,J=11.9Hz,1H),8.32(dd,J=13.8,11.9Hz,1H),6 .60(s,4H),5.38(d,J=13.9Hz,1H),4.22(t,J=6.0Hz,2H),2.88(t,J=6.1Hz,2H). 13 C NMR(101MHz,DMSO-d6)δ167.7,167.6,164.0,142.8,119.1,94.5,58.4,18.1.HRMS(ESI):m / z:[M+H] + Calcd.forC9H 12 N7O2 + :250.1052;Found:250.1056.

[0187] Embodiment 32:

[0188] Synthesis of melamine monoenamine ester derivatives 3.32

[0189]

[0190] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of 1,2-dichloroethane, and then 191.3 mg of 2-(2-methyl-allyloxy)ethyl propiolate and 40.9 mg of zinc chloride were added in sequence. The mixture was reacted at 80°C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with methanol, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.32, with a yield of 80%.

[0191] Melamine monoenamine ester derivative 3.32, white solid, melting point: 180-181℃. 1 H NMR(400MHz,DMSO-d6)δ9.83(d,J=11.9Hz,1H),8.29(dd,J=13.9,11.9Hz,1H),6.55(s,4H),6.03 –6.02(m,1H),5.68(t,J=1.7Hz,1H),5.35(d,J=13.9Hz,1H),4.29(s,4H),1.87(t,J=1.3Hz,3H). 13 C NMR(101MHz,DMSO-d6)δ167.9,167.7,166.9,164.0,142.4,136.1,126.5,94.9,63.2,61.3,18.4.HRMS(ESI):m / z:[M+Na] + Calcd.for C 12 H16 NaN6O4 + :331.1131;Found:331.1136.

[0192] Embodiment 33:

[0193] Synthesis of melamine monoenamine ester derivative 3.33

[0194]

[0195] 126.1 mg of melamine was added to the reaction flask and dissolved with 2 mL of dimethyl sulfoxide. Then 376.5 mg of 3-phenyl propiolate and 106.0 mg of ferric acetylacetonate were added in sequence. The reaction was carried out at 80 ° C for 24 h. After the reaction solution was cooled to room temperature, water was added to precipitate the product, which was filtered, washed with EA, and dried to obtain a white solid, i.e., melamine monoenamine ester derivative 3.33, with a yield of 64%.

[0196] Melamine monoenamine ester derivative 3.33, white solid, melting point: 155-156℃. 1 H NMR(400MHz, DMSO-d6)δ9.80(d,J=11.9Hz,1H),8.28(dd,J=13.9,11.9Hz,1H),7.30–7.27(m,2H),7.22–7.1 8(m,3H),6.55(s,4H),5.36(d,J=13.9Hz,1H),4.02(t,J=6.6Hz,2H),2.65–2.61(m,2H),1.90–1.86(m,2H). 13 C NMR(101MHz,DMSO-d6)δ168.1,167.7,164.0,141.9,141.7,128.8,128.7,126.3,95.5,62.8,31.9,30.5.HRMS(ESI):m / z:[M+H] + Calcd.for C 15 H 19 N6O2 + :315.1569;Found:315.1573.

[0197] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

[0198] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. A melamine monoenamine ester derivative, characterized in that: The general structural formula of the melamine monoenamine ester derivative is shown in Formula I: In Formula I, R is methyl, ethyl, n-propyl, n-butyl, isobutyl, tert-butyl, n-hexyl, 1-methylheptyl, n-octyl, 3,7-dimethyloctyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, cyclopropylmethyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclododecyl, 4-pentenyl, 4-hexenyl, 5-hexenyl, 9-decenyl, 10-carbon undecenyl, 3-cyclopentenylmethyl, 3-cyclohexenylmethyl, 4-pentynyl, 5-hexynyl, 6-heptynyl, 3-nitrilepropyl, 2-(2-methylallyloxy)ethyl, 3-phenylpropyl.

2. A method for preparing the melamine monoenamine ester derivatives according to claim 1, characterized in that: The steps include: Melamine and propiolate are added into a reaction container, and then a catalyst and a solvent are added, and melamine monoenamine ester derivatives are obtained through reaction, separation and purification.

3. The method for preparing the melamine monoenamine ester derivative according to claim 2, characterized in that: The chemical reaction formula is, 4. The method for preparing the melamine monoenamine ester derivatives according to claim 2, characterized in that: The molar ratio of melamine to propiolate is 1:1.05 to 1:

5.

5. The method for preparing the melamine monoenamine ester derivatives according to claim 2, characterized in that: The molar ratio of melamine to catalyst is 1:0.05 to 1:0.

3.

6. The method for preparing the melamine monoenamine ester derivatives according to any one of claims 3 to 5, characterized in that: The catalyst includes at least one of HCl, TsOH, B(C5F6)3, Fe(acac)3, Cu(OTf)2, Fe(OTf)3, Ni(OTf)3, BiCl3, ZnCl2, AlCl3, H2SO4, HI, and HNO3.

7. The method for preparing the melamine monoenamine ester derivatives according to claim 6, characterized in that: The solvent includes at least one of EtOH, H2O, THF, (CH2OH)2, MeCN, DMF, DCE, and DMSO.

8. The method for preparing the melamine monoenamine ester derivatives according to claim 7, characterized in that: The reaction temperature is 50°C to 120°C, and the reaction time is 6 to 24 hours.

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