Novakov et al.
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Russ. Chem. Bull., Int. Ed., Vol. 69, No. 6, June, 2020
ν/cm–1: 3365 (NH2), 3264, 3037, 2963, 2868 (CH), 1647 (NH2),
1587 (C—CAr), 1463, 1445 (CH2), 1370 (CH3), 1293 (C—N),
1052, 1010, 970, 747. MS (EI, 70 eV), m/z (Irel (%)): 242 [M + 1]+
(30.1), 241 [М]+ (100), 226 [М – CH3(Ar)] (1.8), 198 [М –
– C2H4(Ad) – CH3(Ar)] (1.2); 185 [М – C2H4 – CH(Ad) –
– CH3(Ar)] (3.0), 184 (10.0), 170 [М – C2H4 – CH – CH3(Ad) –
– CH3(Ar)] (1.0), 169 (1.0), 147 (1.7), 135 (disubstituted Ad)
(1.1), 130 (1.5), 120 (1.7), 106 (16.1), 77 (1.0). 1H NMR
(300 MHz, CCl4, δ): 1.57 (s, 6 H, H(δ)); 1.87 (s, 6 H, H(β));
2.02 (s, 3 H, H(γ)); 2.02 (s, 3 H, 2-Ме); 3.20 (s, 2 H, NH2);
6.33—6.81 (m, 3 H, Ar). 13C NMR (300 MHz, CCl4, δ): 15.92
(s, C(18)); 27.23 (s, C(3), C(5), C(8)); 33.40 (s, C (1)); 35.23
(all s, C (4), C(9), C(10)); 41.56—41.90 (all s, C(2), C(6), C(7));
112.82 (s, C(12)); 116.90 (s, C(13)); 119.13 (s, C(16)); 121.37
(s, C(15)); 125.06 (s, C(14)); 140.02 (s, C(11)).
The target diamine 5 is formed in high yield (90%), with
minimized amounts of acidic waste and by-products.
Thus, we studied adamantylation of aromatic amino
derivatives and ascertained that TFA is an efficient medium
for the preparation of the desired compounds. Adaman-
tylaminoarenes were synthesized in high yields (83—99%)
and with high purity (95—99%), according to X-ray dif-
fraction data. TFA was found to have a differentiating
effect on the regioselectivity of adamantylation of о-alkyl-
substituted acetanilides, resulting in the formation of
energetically more favorable para-substituted products
with respect to the alkyl group. The use of N-benzylacet-
amide as the aromatic compound leads to C- and N-ada-
mantylation and self-alkylation products formed as a mix-
ture difficult to separate. The predominance of N-alkylation
over C-alkylation is due to higher charge on the nitrogen
atom in N-benzylacetamide compared to acetanilide and
the ease of fragmentation of benzylacetamide in TFA,
which results in dibenzyl- and tribenzylamines.
2-Ethyl-5-(tricyclo[3.3.1.13,7]dec-1-yl)aniline (3´с). Yield
83%, main component content 93%, m.p. 108—110 °C. IR,
ν/cm–1: 3375 (NH2), 3298, 2959, 2896, 2844 (CH), 1621 (NH2),
1620 (C—CAr), 1503 (CH2), 1416, 1315, 1272 (C—N), 1161,
1101, 933, 807, 753 (C2H5). MS (EI, 70 eV), m/z (Irel (%)): 257
[M + 2] (2.8), 256 [M + 1]+ (22.1), 255 [M]+ (100), 240 [М –
– CH3(Ar)] (1.6), 226 [М – C2H5(Ar)] (1.4), 213 [М – CH(Ad) –
– C2H5(Ar)] (3.3), 200 [М – C2H2(Ad) – C2H5(Ar)] (1.4),
199 (8.8), 198 (46.3), 186 (1.9), 185 [М – C2H2 – CH3(Ad) –
– C2H5(Ar)] (1.6), 184 (1.5), 170 [М – C2H2 – CH3 – CH3(Ad) –
– C2H5(Ar)] (12.0), 169 (3.3), 146 (2.3), 135 (disubstituted Ad)
(2.9), 130 (3.0), 119 (1.4), 118 (1.8), 117 (1.2), 106 (1.6), 77 (1.0).
1H NMR (300 MHz, CCl4, δ): 1.23 (s, 3 H, CH2CH3); 1.74
(s, 6 H, H(δ)); 1.86 (s, 6 H, H(β)); 2.02 (s, 3 H, H(γ)); 2.74
(s, 2 H, CH2CH3); 3.20 (s, 2 H, NH2); 6.22—6.73 (m, 3 H, Ar).
2,6-Dimethyl-4-(tricyclo[3.3.1.13,7]dec-1-yl)aniline (3d).
Yield 88%, main component content 97%, m.p. 125—127 °C.
IR, ν/cm–1: 3381 (NH2), 3050, 2899, 2846, 2390 (CH), 1620
(NH2), 1616 (C—CAr), 1591, 1519, 1490, 1477 (CH2), 1379
(CH3), 1321, 1249 (C—N), 1180, 924, 867, 716. MS (EI, 70 eV),
m/z (Irel (%)): 256 [M + 1]+ (20.1), 255 [M]+ (100), 227 [М –
– C2H4(Ar)] (5.1), 212 [М – CH3(Ad) – C2H4(Ar)] (1.9), 199
[М – C2H4(Ad) – C2H4(Ar)] (3.9), 198 (19.1), 185 [М – C2H4 –
– CH3(Ad) – C2H4(Ar)] (1.1), 184 (3.8), 170 [М – C2H4 – CH3 –
– CH3(Ad) – C2H4(Ar)] (1.8), 160 (2.0), 159 (1.9), 146 (2.3),
135 (disubstituted Ad) (45.8), 130 (4.1), 119 (1.0), 117 (1.2), 106
(2.6), 93 (5.8), 91 (5.9), 79 (6.2), 77 (1.0). 1H NMR (300 MHz,
CCl4, δ): 1.79 (s, 6 H, H(δ)); 1.87 (s, 6 H, H(β)); 2.02 (s, 3 H,
H(γ)); 2.04 (s, 6 H, 2-Ме, 6-Me); 3.18 (s, 2 H, NH2); 6.31—6.73
(m, 3 H, Ar).
Experimental
Mass spectra were measured on a Saturn-2100 gas chromato-
graph—mass spectrometer. 1H and 13C NMR spectra were re-
corded on a Mercury 300 plus BB instrument (Varian) (HMDS
as the internal standard; DMSO-d6, CDCl3, and CCl4 as sol-
vents). The 13C nuclei were identified using partial or complete
proton decoupling. The proton decoupled spectra were obtained
using DEPT procedure. The IR spectra were measured on
a Nicolet-6700 FT IR spectrometer (ATR).
Commercial chemicals were used as received.
Quantum chemical calculations were carried out using the
GAMESS (US) software program. The calculations were per-
formed by the density functional theory method using the
B3LYP/6-31G(d) hybrid functional and preliminary geometry
optimization by semiempirical quantum chemical PM3 method.
Synthesis of amines 3a—f (general procedure). Compound
1a,b (0.15 mol), the specified acetanilide (2a—d) (0.21 mol), and
TFA (0.9 mol) were charged into a flat-bottom flask equipped
with a reflux condenser and electromagnetic stirrer (the reactant
molar ratio 1a,b : 2a—d : TFA = 1 : 1.4 : 6). The reaction mixture
was stirred for 3 h at 80 °C. After completion of the reaction, TFA
was distilled off, the residue was hydrolyzed with 10% hydro-
chloric acid and filtered. A 20% sodium hydroxide solution was
added to the filtrate with cooling (up to highly alkaline medium).
The precipitate was collected on a filter and dried in vacuo.
4-(Tricyclo[3.3.1.13,7]dec-1-yl)aniline (3a). Yield 96%, main
component content 99%, m.p. 105—106 °C. IR, ν/cm–1: 3360
(NH2), 2896, 2846, 2646 (CH), 1685 (NH2), 1620 (C—CAr),
1451 (CH2), 1305, 1282 (C—N), 1256, 1183, 1005, 965, 881,
742, 674. MS (EI, 70 eV), m/z (Irel (%)): 228 [M + 1]+ (33.4),
227 [М]+ (100), 185 [М – C3H6(Ad)] (1.2), 184 (5.4), 170
[М – C3H6(Ad) – CH3] (75), 168 [М – C3H6(Ad) – CH3 – 2 H]
(1.2), 133 (disubstituted Ad) (10.6), 130 (2.4), 119 (1.2), 106
(6.2), 91 (4), 77 (4.0). 1H NMR (300 MHz, CCl4, δ): 1.74 (s, 6 H,
H(δ)); 1.87 (s, 6 H, H(β)); 2.04 (s, 3 H, H(γ)); 3.68 (s, 2 H,
NH2); 6.44 (s, 2 H, H(2), H(6)); 7.18 (s, 2 H, H(3), H(5)).
2-Methyl-5-(tricyclo[3.3.1.13,7]dec-1-yl)aniline (3´b). Yield
86%, main component content 94%, m.p. 138—140 °C. IR,
4-(3,5-Dimethyltricyclo[3.3.1.13,7]dec-1-yl)aniline (3e).
Yield 90%, main component content 95%, m.p. 90—91 °C. IR,
ν/cm–1: 3365 (NH2 stretch.), 2898, 2845, 2641 (CH stretch.),
1681 (NH2), 1622 (C—CAr), 1450 (CH2), 1375 (CH3), 1305,
1280 (C—N), 1228, 1182, 1003, 963, 863, 740, 674. MS (EI,
70 eV), m/z (Irel (%)): 256 [M + 1]+ (30.1), 255 [М]+ (100), 226
[М – C2H5 (Me groups of Ad)] (1.8), 198 [М – C2H4(Ad) –
– C2H5 (Me groups of Ad)] (1.2), 185 [М – C2H4 – CH(Ad) –
– C2H5 (Me groups of Ad)] (3.0), 184 (10.0), 170 [М – C2H4 –
– CH – CH3(Ad) – C2H5 (Me groups of Ad)] (1.0), 169 (1.0),
147 (1.7), 135 (disubstituted Ad) (1.1), 130 (1.5), 120 (1.7), 106
(16.1), 77 (1.0). 1H NMR (300 MHz, CCl4, δ): 0.79 (s, 6 H,
Ме(Ad)); 1.52—2.42 (m, 13 H, H(Ad)); 3.21 (s, 2 H, H(NH2));
6.48—6.97 (m, 4 H, H(Ar)).
4-(3,5-Dimethyltricyclo[3.3.1.13,7]dec-1-yl)-2,6-dimethyl-
aniline (3f). Yield 89%, main component content 94%, m.p.
94—97 °C. IR, ν/cm–1: 3380 (NH2), 3051, 2895, 2844, 2391