Конденсация S-замещенных 6-амино-2-тиоурацилов с бензальдегидами

Abstract

In the present study 5,5'-(phenylmethylene) bis (2-organylsulfanyl-6-aminopyrimidin-4(3 H )-ones) were obtained by the interaction of 2-allylsulfanyl-, 2-methallylsulfanyl- and 2-propargylsulfanyl-6-aminopyrimidin-4(3 H )-ones with benzaldehyde with ratio of 2:1 in concentrated acetic acid at room temperature. At the same conditions 5,5'-((4-(dimethylamino)phenyl)methylene) bis (2-organylsulfanyl-6-aminopyrimidin-4(3 H )-ones) and 5,5'-((3,4-dimethoxyphenyl)methylene) bis (2-benzylsulfanyl-6-aminopyrimidin-4(3 H )-one) were prepared by the reaction of 2-allylsulfanyl-, 2-benzylsulfanyl-, 2-propargylsulfanyl-6-aminopyrimidin-4(3 H )-ones with 4,4-dimethylaminobenzaldehyde and 2-benzylsulfanyl-6-aminopyrimidin-4(3 H )-one with 3,4-dimethoxybenzaldehyde, respectively. The initial 2-organylsulfanyl-6-aminopyrimidin-4(3 H )-ones were prepared by the known method of 6-amino-2-thiouracil alkylation by organylhalides (allyl bromide, methallyl chloride, propargyl bromide, benzyl chloride) in aqueous ethanol at room temperature in the presence of alkali. The structures of dipyrimidines were confirmed by 1 H NMR spectroscopy and gas chromatography–mass spectrometry. The NMR spectra were recorded on a Bruker DRX-400 and a Bruker AVANCE-500 spectrometers. The mass spectra were obtained on a Shimadzu GCMS-QP2010 Ultra instrument. The 1 H NMR spectra of obtained dipyrimidines contained no singlets of the pyrimidine ring characteristic for the 5-H proton at δ 4.90–5.05 ppm, but they contained the signals of the CHPh proton at δ 5.35–5.50 ppm. The monosubstituted phenyl ring had signals at δ 7.00–7.25 ppm, while the protons of di- and trisubstituted phenyl ring characteristically appeared in a higher field at δ 6.55–6.90 ppm and 6.60–6.70 ppm, respectively. The characteristic features of all analyzed mass spectra were the molecular ion peak, as well as the C 5 -CHPh bond rupture and formation of phenyl cation. The mass spectra of all studied compounds contained peaks, characteristic for fragmentation of initial 2-organylsulfanyl-6-aminopyrimidin-4(3 H )-ones. Interaction with aromatic aldehydes proceeded in two stages, which was proved by the formation of 6-amino-5-(hydroxy(phenyl)methyl)-2-methallylsulfanylpyrimidin-4(3 H )-one and 5,5'-(phenylmethylene) bis (2-­methallylsulfanyl-6-aminopyrimidin-4(3 H )-one) mixture in the reaction of 2-methallylsulfanyl-6-aminopyrimidin-4(3 H )-one with benzaldehyde with equimolar ratio. All attempts to obtain the tricyclic system, namely, substituted pyrido[2,3- d :6,5- d ’] dipyrimidines by the intermolecular elimination of the ammonia molecule were unsuccessful. The reaction of 5,5'-(phenylmethylene) bis (2-allylsulfanyl-6-aminopyrimidin-4(3 H )-one with iodine led to formation of 6,6'-(phenylmethylene) bis (5-amino-3-(iodomethyl)-7-oxo-2,3,7,8-tetrahydrothiazolo[3,2- a ]pyrimidinium) iodide, as proved by 1 H NMR. The 1 H NMR spectrum contained the characteristic signal of the NCH + proton at δ 5.29 ppm.