SYNTHESIS OF 1,3-DIOXACYCLAN-2-YL-SUBSTITUTED 1,2,3-TRIAZOLES
5
and phenylpropynal 2 were obtained by the previously
(B) From 1-phenyl-3,3-diethoxyprop-1-yne 1. An
developed procedure [11], the physicochemical char- appropriate compound of 6a–6e series (5 mmol) was
acteristics of heterocyclic aldehyde 3 agree well with added to a solution of 0.34 g (5.25 mmol) of NaN3 in
the literature data [12]. The preparation of cyclic
acetals 6a–6e is described by us in the work [9].
10 mL of dry DMSO. The solution was heated at 150–
155°C for 8–10 h until complete transformation of
compounds 6a–6e (control by TLC), and then the
solvent was removed in a vacuum. The solid residue
was washed on a filter with 10 mL of dry benzene and
dried in air for 10–15 min. Ten milliliters of water and
next HCl (1 : 1) was added to the obtained salt to
pH 4–5. The product was extracted with diethyl ether
(3 × 15 mL), the extract was dried with Na2SO4, the
solvent was removed in a vacuum, and the residue was
kept at 20–25 mmHg for 1–1.5 h.
Procedure for the preparation of 1-phenyl-3,3-
diethoxyprop-1-yne (1) [11]. A solution of 24.5 g
(0.24 mol) of phenylacetylene in 50 mL of ether was
added to a solution of 0.26 mol of EtMgBr (from
6.34 g of Mg and 28.3 g of EtBr) in 250 mL of anhy-
drous diethyl ether on cooling with water. The reac-
tion mixture was heated under reflux for 4–5 h, 39 g
(0.26 mol) of triethyl orthoformate was added, and the
mixture was heated under reflux for additional 7–8 h.
The complex was decomposed by addition of 100 mL
of saturated NH4Cl solution dropwise on cooling, next
the organic layer was separated, and the aqueous layer
was extracted with ether (3 × 30 mL). The organic
layer and the ethereal extracts were combined and
dried with Na2SO4, the solvent was removed, and the
residue was distilled in a vacuum. Yield 90%, bp 144–
148°C (12 mmHg) (bp 144–145°C (14 mmHg).
4-(1,3-Dioxolan-2-yl)-5-phenyl-1,2,3-triazole (5a).
Yield 24% (procedure A), 70% (procedure B). Color-
1
less powder, mp 56–57°C. H NMR (CDCl3, δ,
ppm): 3.80–4.20 (m, 4H, H4,5), 6.16 (s, 1H, H2),
7.13–7.64 (m, 3H, HAr), 7.13–7.95 (m, 2H, HAr), 10.17
(br s, 1H, NH). MS (m/z (Irel, %)): 216 (100) [M–1]+,
189 (43), 172 (46), 130 (13), 117 (22), 102 (20), 89 (30),
73 (78), 63 (15), 51 (17).
Procedure for the preparation of phenylpropy-
nal (2) [11]. A mixture of 0.05 mol of acetal 1, 10 mL
of 5% aqueous solution of H2SO4, and 7.5 mL of
AcOH was heated on stirring (70–80°С) for 1 h, while
distillate was distilled off under slightly reduced pressure.
The reaction mixture after cooling and distillate were
treated with crystalline NaHCO3 to pH 6–7 and com-
bined, the product was extracted with ether (3 × 30 mL).
The extract was dried with Na2SO4, the ether was
removed, and the residue was distilled in a vacuum
under nitrogen atmosphere. Yield 92%, bp 118–121°С
(40 mmHg).
General procedure for the preparation of acetylene
dioxacyclanes (6a–6e) [9]. A solution of 0.05 mol of
acetal 1, 0.055 mol of diol 4a–4e, and 100 mg of tolue-
nesulfonic acid in 50 mL of benzene was heated under
reflux, while a fraction containing benzene and ethyl
alcohol was distilled off. As distillate was distilled off,
fresh solvent was added to the boiling solution. The
distillation was carried out until the absence of ethanol
in distillate according to gas-liquid chromatography.
The reaction mixture was cooled, washed with NaH-
CO3 solution, dried with Na2SO4, benzene was
removed, and the residue was distilled in a vacuum.
Synthesis of 4-(1,3-dioxacyclan-2-yl)-5-phenyl-
1,2,3-triazoles (5a–5e). (A) From aldehyde 3. Tolue-
nesulfonic acid (100 mg) was added to a solution of
3.1 g (0.018 mol) aldehyde 3 and 1.5 g (0.024 mol) of
ethylene glycol 4a in 20 mL of benzene and the mix-
ture was heated under reflux using a Dean–Stark dis-
tilling trap until water evolution ceased. The reaction
mixture was cooled, washed with NaHCO3 solution,
dried with Na2SO4 and the solvent was removed in a
vacuum. Compound 5a was isolated by chromatogra-
phy on silica gel (EtOAc : petroleum ether = 1 : 1).
Yield 0.88 g (23%).
For C11H11N3O2 anal. calcd. (%): C, 60.82; H, 5.10.
Found (%): C, 60.57; H, 5.19.
4-(4-Methyl-1,3-dioxolan-2-yl)-5-phenyl-1,2,3-
triazole (5b). Yield 20% (procedure A), 30% (proce-
1
dure B). Colorless viscous oil. H NMR (CDCl3, δ,
ppm): 1.14–1.36 (m, Me), 3.47–3.70 (m, H4,5), 4.09–
4.14 (m, H4,5), 4.30–4.50 (m, H4,5), 6.14 (s, H2), 6.29
(s, H2), 7.32–7.46 (m, HAr), 7.75–7.78 (m, HAr), 7.93–
7.97 (m, HAr), 10.88 (br s, NH). MS (m/z (Irel, %)):
230 (60) [M–1]+, 189 (52), 172 (100), 158 (12), 144
(10), 130 (15), 117 (19), 103 (17), 87 (43), 77 (19), 59
(35), 51 (10).
For C12H13N3O2 anal. calcd. (%): C, 62.33; H, 5.67.
Found (%): C, 62.46; H, 5.77.
4-(4-Propyl-1,3-dioxolan-2-yl)-5-phenyl-1,2,3-
triazole (5c). Yield 23% (procedure A), 54% (proce-
1
dure B). Colorless viscous oil. H NMR (CDCl3, δ,
ppm): 0.84–0.98 (m, Pr), 1.21–1.76 (m, Pr), 3.49–
3.70 (m, H4,5), 4.06–4.35 (m, H4,5), 6.16 (s, H2), 6.28
(s, H2), 7.28–7.48 (m, HAr), 7.71–7.84 (m, HAr),
7.96–7.99 (m, HAr), 11.58 (br s, NH). MS (m/z (Irel,
%)): 259 (65) [M]+, 189 (62), 172 (100), 158 (21), 145
(5), 115 (20), 103 (15), 89 (13), 77 (12), 69 (61).
For C14Н17N3О2 anal. calcd. (%): C, 64.85; H, 6.61.
Found (%): C, 64.71; H, 6.43.
4-(4-Methyl-1,3-dioxan-2-yl)-5-phenyl-1,2,3-tri-
azole (5d). Yield 24% (procedure A), 61% (procedure
B). Colorless viscous oil. 1H NMR (CDCl3, δ, ppm):
1.22–1.35 (m, Me), 1.50–1.54 (m, Me), 1.83–1.97
(m, H4,5,6), 3.50–3.57 (m, H4,5,6), 3.90–4.07 (m,
H4,5,6), 4.25–4.30 (m, H4,5,6), 5.90(s, H2), 6.29 (s, H2),
7.35–7.46 (m, HAr), 7.81–7.90 (m, HAr), 11.57 (br s,
NH).MS (m/z (Irel, %)): 245 (65) [М]+, 189 (100), 172
DOKLADY CHEMISTRY Vol. 472 Part 1 2017