Nꢀ3ꢀPhosphonopropyl αꢀamino acids
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 11, November, 2005 2637
Table 3. Parameters of the IR spectra (KBr) and 13C NMR spectra (D2O) of compounds 4, 7, and 8
Comꢀ
pound
IR,
ν/cm–1
13C NMR,
δ, J/Hz
4a
4b
7a
3500—2000 (NH2+, OH),
1742 (C=O), 1101, 1059 (PO2
3500—2000 (NH2+, OH),
1715 (C=O), 1106, 1060 (PO2
3500—2000 (NH2+, OH),
1727 (C=O), 1151 (P=O)
19.88 (d, CH2CH2CH2, J = 3.8); 24.39 (d, PCH2, J = 135.3);
47.71 (s, NCH2CO); 47.84 (d, NCH2CH2, J = 18.0); 169.56 (s, CO)
14.31 (s, CH3); 20.07 (d, CH2CH2CH2, J = 2.8); 24.40 (d, PCH2,
J = 135.5); 46.35 (d, NCH2, J = 17.1); 56.11 (s, CH); 172.92 (s, CO)
18.10 (s, CH2CH2CH2); 25.05 (d, PCH2, J = 72.3); 47.39 (s, NCH2CO);
47.47 (d, NCH2CH2, J = 16.0); 129.21 (d, mꢀC(Ph), J = 12.4);
129.34 (d, ipsoꢀC(Ph), J = 102.4); 130.54 (d, oꢀC(Ph), J = 10.0);
133.05 (s, pꢀC(Ph)); 169.01 (s, CO)
14.44 (s, CH3); 19.36 (d, CH2CH2CH2, J = 3.2); 26.45 (d, PCH2,
J = 72.3); 46.68 (d, NCH2CH2, J = 14.4); 55.82 (s, CH); 129.40
(d, mꢀC(Ph), J = 12.1); 131.10 (d, oꢀC(Ph), J = 9.6); 131.70 (d, ipsoꢀC(Ph),
J = 101.0); 131.77 (d, ipsoꢀC(Ph), J = 101.5); 132.90 (d, pꢀC(Ph), J = 2.4);
171.00 (s, CO)
–
–
)
)
7b*
3500—2000 (NH2+, OH),
1719 (C=O), 1147 (P=O)
8a
8b
3150—2000 (NH2+),
1619, 1383 (CO2–),
1183 (P=O)
16.51 (br.s, CH2CH2CH2);
23.33 (d, PCH2, J = 72.3); 45.72 (d,
NCH2CH2, J = 17.3); 47.40 (s, NCH2CO); 127.53 (d, mꢀC(Ph), J = 12.0);
127.68 (d, ipsoꢀC(Ph), J = 102.0); 128.95 (d, oꢀC(Ph), J = 10.0);
131.40 (br.s, pꢀC(Ph)); 169.33 (s, CO)
14.23 (s, CH3); 17.72 (br.s, CH2CH2CH2); 24.36 (d, PCH2, J = 72.5);
45.41 (d, NCH2CH2, J = 16.7); 57.14 (br.s, СН); 128.50 (d, mꢀC(Ph),
J = 12.1); 128.60 (d, ipsoꢀC(Ph), J = 101.5); 129.90 (d, oꢀC(Ph), J = 10.1);
132.40 (br.s, pꢀC(Ph)); 173.90 (br.s, СО)
3150—2000 (NH2+),
1585, 1394 (CO2–),
1184 (P=O)
* The 13C NMR spectrum of compound 7b was recorded in CD3OD.
pholanium salts 5 (Scheme 2), which were obtained in
the reaction of diphenylphosphinous chloride (6) with
amino acid derivatives 3a,b. Hydrochlorides 7a,b are highꢀ
melting crystalline products, which are moderately soluble
in MeOH and EtOH and readily soluble in water (see
Tables 1—3).
absorption bands at 3500—2000 cm–1 corresponding to
stretching vibrations of NH2+ and OH groups involved in
strong hydrogen bonds (see Table 3). These data are conꢀ
sistent with the presence of phosphoryl, carboxy, and
+
NH2 groups in hydrochlorides 7a,b. The structure of
hydrochloride 7a was confirmed by Xꢀray diffraction.
Hydrochloride 7a crystallizes with two independent catꢀ
ions and anions per asymmetric unit (Fig. 1). The nitroꢀ
gen atoms in both independent cations are protonated.
The bond lengths and bond angles and the allꢀtrans conꢀ
formation of the P(1)—C(5) fragment in two indepenꢀ
dent cations of 7a are virtually identical (Table 4). The
phosphoryl group is synperiplanar (sp) to the alkyl
chain. However, one independent molecule adopts the
+sp conformation, whereas another molecule is in the
–sp conformation. The O(1)—P(1)—C(1)—C(2) and
O(1´)—P(1´)—C(1´)—C(2´) torsion angles are 39.5 and
–41.3°, respectively.
Scheme 2
In the crystal structure of 7a, the cations are linked
to each other by strong O—H...O hydrogen bonds beꢀ
tween the carboxy and phosphoryl groups (O(3)...O(1´)
and O(3´)...O(1) are 2.561(2) and 2.530(2) Å, respecꢀ
tively) to form chains along the crystallographic axis b.
These chains are additionally crossꢀlinked by the Cl– anꢀ
ions through the N—H...Cl hydrogen bonds (N...Cl,
3.026(2)—3.071(2) Å).
R = H (a), Me (b)
Reagents and conditions: i. 1) Et3N, –5 °C, CHCl3—C6H6,
2) ∆, 1 h. ii. 6 M HCl, ∆. iii. Methyloxirane, 20 °C.
The reactions of hydrochlorides 7a,b with methylꢀ
oxirane produced Nꢀ(3ꢀdiphenylphosphorylpropyl)glycine
(8a) and ꢀDLꢀalanine (8b), respectively. These highꢀmeltꢀ
The IR spectra of compounds 7a,b have absorption
bands of P=O and C=O groups along with broad intense