ChemInform Abstract: Synthesis and Acylation of 4‐Chloroalkyl‐3,4‐dihydropyrimidin‐2(1H)‐ones.

Abstract

Synthesis and Acylation of 4-Chloroalkyl-3,4-dihydropyrimidin-2(1H)-ones. -(KOLOSOV*, M. A.; KULYK, O. G.; AL-OGAILI, M.; ORLOV, V. D.; Z. Naturforsch., B: Chem. Sci. 67 (2012) 9, 921-924, http://dx.doi.org/10.5560/znb.2012-0182 ; Dep. Org. Chem., Karazin Natl. Univ., Kharkov 61022, Ukraine; Eng.) -M. Paetzel 05-133

Synthesis and N-alkylation of diethyl 4,7-dihydroazolo[1,5-a]pyrimidin-5,6-dicarboxylates

“…It is interesting that unlike the above-mentioned alkylation of 6-acetyl-5-methyl-7-phenyl-4,5-dihydro [1,2,4]triazolopyrimidine [8] the process in this case occurred selectively (which was favoured by 1 H NMR-spectra of the products obtained). In contrast to the 1 H NMR spectrum of the initial compounds 5, the signal of NH-protons is absent in a low field, but the signal of NCH 3 -group is present.…”

“…This approach has worked well for the synthesis of 5-COR-4-aryl-3,4-dihydropyrimidin-2(1H)-ones derivatives [9,10] and along with Atwal modification of Biginelli reaction is widely used in laboratory practice [11][12][13][14]. 1 H NMR-spectra of the compounds obtained contain the signals of N(4)-protons in low fields, the signals of aromatic protons, the singlet of C (7)H-proton and the signals of two EtO-groups. Besides, for compound 5a the signal of C(2)-proton at 7.70 ppm (separately from aromatic protons signals) is observed.…”

“…triazolo [1,5-a]pyrimidin -5,6-dicarboxylate) it has been found that alkylation of 4,7-dihydro [1,2,4]azolo [1,5-a]pyrimidin -5,6- [1,2,4] triazolo [1,5-a]pyrimidines are the promising objects for studying benzyl C(7)-functionalization of 4,7-dihydroazolo [1,5-a] [1,2,4] triazolo-and tetrazolo [1,5- [1,2,4]triazolo-and tetrazolo [1,5-a] [1,2,4]триазоло [1,5-a] Previously we reported about the synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives of type 1 and 2 (Fig. 1).…”

“…Besides, for compound 5a the signal of C(2)-proton at 7.70 ppm (separately from aromatic protons signals) is observed. It is also worth noting that the signal of one of the CH 2 -groups (3.82-4.07 ppm for compound 5а) like the spectrum of 6-acetyl-4-ethyl-5-methyl-7-phenyl-4,5-dihydro [1,2,4]triazolopyrimidine [8] is a multiplet, and it indicates its diastereotopism. Diastereotopism of the second CH 2 -group does not reveal obviously because of the presence of flexible bonds between the ethoxycarbonyl group and the dihydrocycle, which contains a chiral centre, as well as due to a rather long distance from the CH 2 -group to the chiral centre.…”

“…As the addition to the compounds previously obtained [1] we synthesized 6-unsubstituted 3,4-dihydropyrimidin-2(1H)-ones 1c,d by the reaction of aromatic aldehydes, urea and ethyl 3,3-diethoxypropanoate in HOAc (Scheme 3).…”