Synthesis, characterization and biological activity of bis(3‐Aryl‐1‐hexahydropyrimidinyl)methanes. Novel heterocyclic polyamine derivatives

Abstract

A method is described for the synthesis of bis(3-aryl-1-hexahydropyrimidinyl)methanes 1, by condensation of N-aryl-1,3-propanediamines 2 with formaldehyde. The reaction mechanism involves N-arylhexahydropyrimidines 3 as intermediates. Such compounds can also be prepared efficiently by a methylene exchange reaction between bis-hexahydropyrimidines 1 and the corresponding diamines 2. The antimicrobial activity of compounds 1 was evaluated by the disk diffusion method and some of them showed moderate to good growth inhibition activity.

Modular Synthesis of Heterocyclic Carbene Precursors

“…N -Mesitylpropylenediamine (8f). Starting from 7f (5.00 g, 21.5 mmol) and LiAlH 4 (3.27 g, 86.1 mmol) in 125 mL of THF, 8f was obtained (2.77 g, 14.4 mmol, 67%) as a pale yellow oil: 1 H NMR (CDCl 3 , 250 MHz) δ 6.83 (s, 2H), 3.00 (t, 2H, J = 6.7 Hz), 2.85 (t, 2H, J = 6.8 Hz), 2.27 (s, 6H), 2.24 (s, 3H), 1.9 (br s, 3H), 1.74 (quint., 2H, J = 6.7 Hz); 13 C NMR (CDCl 3 , 62.5 MHz) δ 143.5, 130.9, 129.4, 129.2, 46.7, 40.3, 34.5, 20.3, 18.1; IR (KBr) 3360, 2942, 2860, 2839, 1483, 1230, 852 cm -1 . Anal.…”

Reaction of trifluoromethyl 1,3-dicarbonyl compounds with formaldehyde and esters of natural α-aminoacids

“…This compound was isolated in 63% yield by column chromatography on SiO2 as a crystalline compound with m.p. 77-78 °C; 19 none of the expected hexahydropyrimidines was found. Scheme 2.…”

“…Though salt 7 forms good crystals, we failed to obtain an X-ray analysis. Nevertheless, its structure was totally confirmed by 1 H, 13 C, 15 N, and 19 F NMR spectroscopy with the use of 2D techniques and gradient pulse sequences, viz., COSY, TOCSY, NOESY, DOSY, HSQC, HMBC, 15 N-HMBC, 19 F-HMBC and 19 F-HOESY, and the data completely match the ionic form described. This is also confirmed by HRMS ESI data (in positive mode) that directly show that the cation of this salt is present.…”

Synthesis of tetrahydropyrimidinium salts and their in situ catalytic activities towards the Buchwald--Hartwig amination reaction under microwave irradiation

“…Following a literature report, 16 reaction of 1-aryl-propyl-1,3-diamine with aqueous formaldehyde in methanol produced bis-(3-aryl-hexahydropyrimidinyl)methane. Bis(3-aryl-hexahydropyrimidinyl)methane (1.98 mmol)…”