Kabachnik-Fields reactions of 2,3-Trimethylene-1,2,3,4-dihydrobenzo[2,3-d]pyrimidin-4-on

. In this research article, 2,3-trimethylene-3,4-dihydrobenzo[2,3-d]pyrimidin-4-one was synthesized from 2-aminobenzoic acid and pyrrolidone-2 in the presence of various substances, such as PCl 5 , POCl 3 . Its reduction reaction with NaBH 4 was carried out. The resulting three-component coupling of 2,3-trimethylene-1,2,3,4-tetrahydrobenzo[2,3-d]pyrimidin-4-one-carbonyl, amine, and hydrophosphoryl leads to α - aminophosphonates. Phosphate acid – formaldehyde; aldehydes in the three-component system; and the synthesis of aminomethylphosphonic acid is based on the condensation reaction. During the experiment, 2,3-trimethylene-3,4-dihydrobenzo[2,3-d]pyrimidin-4-one was obtained in the amount of 74%. The yield of the reaction product was increased in resyntheses. The structures were confirmed by IR and 1H NMR spectroscopies. Using NaBH 4 , the experiment was repeated and the product obtained from the synthesis of 2,3-trimethylene-1,2,3,4-tetrahydrobenzo[2,3d]pyrimidin-4-one was obtained in high yield. Additionally, 2,3-trimethylene-1,2,3,4-tetrahydrobenzo[2,3-d]pyrimidin-4-one and related aminophosphonic acids three ring molecules were synthesized in high yield.


Introduction
In the world, the synthesis of new physiologically active derivatives of benzo [2,3d]pyrimidine and the creation of modern drugs based on them are carried out with the help of high technologies.It is known that the anti-cancer drugs used up to now destroy dangerous cancer cells while simultaneously damaging healthy cells.
Representatives of benzo [2,3-d]pyrimidines, preferred palbocyclic anticancer drugs, pyremid and pyrumid acids with antibacterial effects have been developed by world scientists.These medical institutions have a practical interest in the properties of this substance.
One-pot Kabachnik-Fields reaction by acidic or basic catalysts, microwave irradiation or heating [33].Due to the aforementioned factors, we have reported in this paper the synthesis of α-aminophosphonates with high yield using a recyclable catalyst for medical and industrial applications.
The 1st infrared spectrum shows characteristic absorption bands for amidocarbonyl groups (NC=O) at 1683 cm -1 and C2=N1 double bond absorption bands at 1625 cm -1 .
In the 1H NMR spectrum, the aromatic protons of 1 (NaBH4) are in weak fields at 7.31-7.34ppm in the same copy of duplicates (1H, dd, J=4.6, 7.9, H-6), 8.48-8, 53 (1H, ppm) is observed (Figure 2).The ESI-MS spectrum of the reaction product produces a strong molecular [M+H] ion at m/z 190, which assigns the molecular mass of the fragment to 189 and together with 1H NMR spectral data lead to the molecular formula of C10H11N2O.
After reduction, the absorption band 1 at 1625 cm -1 (C=N) disappears in the IR spectrum.The absorption band of the carbonyl group at C is 4, which opens at 1718 cm -1 (CO), and shifts to low-frequency regions (1654 cm -1 ) in the initial connection.Selective reduction of saturated N1-C results in 2 bonds (reduction product 2).

Results and discussion
One-pot, three-component reaction of 2,3-trimethylene-1,2,3,4 with dihydrobenzo [2,3d]pyrimidin-4-one, p and m-nitro-benzaldehyde and phosphoric acid in preliminary experiments optimization of reaction conditions was selected as the model reaction for The procedures followed for the synthesis of α-aminophosphonates in this research work are shown in rows 3-5 of Table 1.Product α-aminophosphonates were obtained by solvent-free microwave irradiation of aldehyde, amine, and phosphoric acid for 1 min.In toluene, without any catalyst, the resulting product was well formed (Figures 3 and 4).Thin layer chromatography (TLC) was used to monitor the reaction and determine the purity of the products.The reaction was carried out with a catalytic amount of HCl in toluene for 30 min.All named compounds are readily soluble in polar organic solvents.
The IR spectra of compounds (3)(4)(5) showed N-CH2 and the bands at 1550 cm -1 merged.It was caused by a sharp band observed at 1240-1291 cm -1 (P=O), and a band for P-C stretching appeared at 740-770 cm -1 .All stretching frequencies are compiled in Table 2. H NMR spectra of compounds (3)(4)(5) in 1DMSO-d6 solvent were recorded.Aromatic protons of α-aminophosphonic acids appeared as a multiplet in the d-6.15-8.69region.The proton of the P-C-H group was brought as a multiplet in the d 3.77-4.86range.In toluene, without any catalyst, the product was in good yield, and the reaction time was 2 to 3 hours, which is quite short and convenient.
Synthesis of compound 2. 30 g (0.78 mol) of sodium borohydride was added to 350 ml of alcohol.The reaction mixture was boiled in a water bath for 3 hours and left for twentyfour hours.The solvent was removed, the remaining product was dissolved in water and left for 1 hour.The precipitate was filtered, washed 3 times with water, dried and recrystallized from hexane.The yield of compound 2 was 28.35 g (91%) at Ts= 136-139ºC [Rf =0.58 (10:1 chloroform-methanol)].

Conclusions
A new method for the preparation of 2,3-trimethylenebenzo[2,3-d]-pyrimidin-4-one condensation with a lactam.performs selective update of 'sh gardens.Synthesis of a novel αaminophosphonic acid was achieved in high yield using single-ring tri-cata.

Table 1 .
90% yield under reaction time and different reaction conditions.

Table 2 .
Elemental analysis and IR data of compounds.