Synthesis and X-ray structure of 3, 3′-diethoxycarbonyl-2, 2′- diethoxy-1, 1′- binaphthyl

Li Lijun, Li Cuizhe, Zhang Dahai, Zang Jiechao
(a, College of Chemistry and Environment Science, Hebei University, Baoding 071002; b, department of chemistry, Handan college, Handan 056005)

Received Nov. 28, 2008; Supported by the fund from the Natural Science Foundation of Hebei Province (No. B2007000152) and Plan Item of Hebei Province Science-Technology Department (05215104)

AbstractA novel 3,3′-BINOL derivative: 3,3′-diethoxycarbonyl-2,2′- diethoxy-1,1′- binaphthyl(2) was synthesized and its structure was characterized by IR, H NMR, 13C NMR and X-ray diffraction.
Keyword 3, 3′-diethoxycarbonyl-2, 2′- diethoxy-1, 1′- binaphthyl, synthesis, characterization

Optically active BINOL and its derivatives are the most prominent C-symmetric, axial-chiral ligands,they are well known to apply in asymmetric catalysis and chiral recognition[1-4]This is because: BINOL and its derivatives have a chair backbone which can be modified. Substitution of BINOL may affect not only the steric environment around the coordinated metal center but also the electronic properties of the oxygen atoms, which are common constituents of the Lewis acidic metal complexes [5-6]. BINOL itself, however, does not always give satisfactory results in asymmetric catalysis, and there has been an ongoing interest in modified BINOL ligands[7-8] since people’s discovery.
This paper firstly synthesized BINOL-3,3dicarboxylic acid (1) under microwave irradiation with iron(III) chloride hexahydrate as catalyst, then a new BINOL derivative 3,3′-diethoxycarbonyl-2,2′- diethoxy-1,1′- binaphthyl (2) was synthesized by substitution reaction.The synthetic routes were outlined in Scheme 1And its structure was characterized through IR, H NMR, 13C NMR and X-ray diffraction, and emphatically analyses its X-ray date.


2.1 Materials and general methods
Commercial reagents were used without further purification unless otherwise noted. The melting points were determined using a digital melting point apparatus. IR spectrawere recorded on a Nicolet AVATAR-37ODTGS Spectrophotometer in the region 4000400 cm-1 KBr discs. H NMR and 13C NMR spectra were recorded on a Bruker Avance-400 superconduct nuclear magnetic resonance instrument, in which chemical shift values are reported in ppm (d) relative to TMS as internal standard. X-ray date was recorded on Rigaku Saturn X ray diffractometer at room temperature.
2.2 Syntheses of 1
The BINOL-3, 3dicarboxylic acid was synthsized according to reported mothed [9]. Iron(III) chloride hexahydrate (20.3g, 56mmol) and 3-hydroxy-2-naphthoic acid fully mixed grind, the mixture was transferred to 100mL beaker, put into a commercial microwave oven Galanz WD800G, set P=20%, t=30s, took out the breaker and stired fully, then put into microwave oven, repeatedly ,till the time of reaction arrived to 740s. The solid was washed by 100mL mixed solution of 36%HCl and HO (v/v=1/1), and was collected by vacuum filtration, then purified by column chromatography using ethyl acetate: petroleum ether (3:1, v/v) as the eluent. The main peak was concentrated to afford BINOL-3, 3’dicarboxylic acid (7.0 g, 18.7mmol) as a yellow solid. Yield: 91%; Mp 295297(Lit.[10]Mp>290); H NMR ((CDCO, 400 MHz):7. 147. 17 (m ,2H ,Ar-H) ,7. 397. 42(m ,4H ,Ar-H) ,8. 098. 11(m ,2H ,Ar-H) ,8. 84( s ,2H ,Ar-H); IR ( KBr) 3059( s ,O-H) ,1661( s ,C =O) ,1499,1455 , 1 272, 1 228 , 1 150 , 1 072 , 886 , 796 , 736cm– 1 .
2.3 Syntheses of 2
At room temperature, compound 1 (0.37g, 1mmol) and NaH(52% dispersion in mineral oil; 0.12g, 2.62 mmol) was added in 5mLDMF, then the mixture was allowed to warm to 50, and stirring for 1.5 h.. After that 1.5mL CHCHBr was slowly added. Every hour NaH 80mg (1.78mmol) was added in mixture. Tracking the reaction by TLC, until compound 1 reacted completely. Then 10mL HO was added to the mixture, extracted with ethyl acetate (3×50mL). The combined organic layers were dried over MgSO and the solvent was removed under reduced pressure. The solid residue was dissolved in ethyl acetate and purified by column chromatography to afford the compound 2 (0.37g, 77%) as a white solid; Mp:104C. IR (KBr):2978, 2932, 2898,1725, 1622,1587,1447,1385, 1364, 1339, 1296, 1271, 1227, 1145, 1108, 1070, 1033, 907, 795, 754, 711cm-1; H NMR(CDCl , 500MHz): 0.78-0.81 (t ,3H ,COOCHCH) ,1.42-1.45 (t, 3H, OCHCH), 3.47-3.53 (m, 2H, OCHCH), 3.87-3.93 (m, 2H, OCHCH), 4.43-4.47 (q, 4H, COOCHCH ), 7.13-7.15 (d ,2H ,Ar-H) ,7. 30~7.33(m ,2H ,Ar-H) , 7.41-7,44 (m ,2H ,Ar-H), 7. 95-7. 96(d , 2H ,Ar-H) , 8. 48 ( s , 2H , Ar-H); 13C NMR (CDCl,125 MHz) d: 14.3, 15.3, 61.3, 70.3, 77.0, 125.3, 125.7, 125.9, 126.5, 128.2, 129.0, 129.4, 132.7, 135.6,153.7, 166.8.
2.4 X-ray crystallography
Crystals of compounds 2 were grown by liquid–liquid diffusion. Mixed solvent of DMSO:HO=1:1(v/v)

Table 1.Crystal data and structure refinement for 2

Empirical formula 3030 range for data collection 2.71 to 27.63°
Formula weight 486.54 Limiting indices -14 < h < 12
Temperature (K) 293(2) -20 < k < 20
Wavelength(Å) 0.71073 -20 < l < 20
Crystal system Monoclinic Reflections collected 19223
Space group P21 /n Independent reflections 5903 (Rint = 0.0397)
a(Å) 11.138(18) Completeness to 97.8 %
b(Å) 15.60(3) Goodness-of-fit on F 1.061
c(Å) 15.80(3) Data / restraints / parameters 5903 / 0 / 330
Volume(Å 2596(7) R1(R1 all data) 0.0915
    wR2 0.1980
Dcalcd (Mg/m 1.254 Largest diff. peak and
hole eÅ-3
0.267 and -0.241
(mm-1 0.086
F(000) 1032

Table2 Selected bond and distance (Å) and angles (°) of 2

C(1)-C(11) 1.496(4) C(21)-O(6) 1.204(3)
C(22)-O(1) 1.189(3) O(4)-O(6) 2.865
O(2)-O(3) 2.730
C(2)-C(1)-C(11) 120.62(19) C(10)-C(1)-C(11) 118.56(16)
C(20)-C(11)-C(1) 119.03(06) C(12)-C(11)-C(1) 120.16(17)
C(12)-O(4)-C(27) 116.34(17) C(2)-O(3)-C(25) 115.63(17)
O(5)-C(11)-O(6) 2.246(4) O(1)-C(22)-O(2) 121.6(2)

2 mL was added to the tube; compounds2 (9.7mg, 0.02mmol) were dissolved in 2ml DMF, was then slowly added along the sides of the tube via a pipette so that the solution was not disturbed, forming the upper layer. The tube was then covered and the solvents were allowed to slowly diffuse at room temperature. After 7 days, colorless prism crystal was found.
The resultant crystals were separated from the solution by decanting. Suitable X-ray quality crystals were recovered and mounted using epoxy glue. Data were collected on a Bruker SMART APEX CCD area detector diffractometer. SAINT (Bruker, 1998), SHELXTL (Bruker, 1998) and SHELXS 97 [11-12] were used for cell refinement, data reduction and structure solving and refinement of structure. Molecular graphics and publication materials were prepared using SHELXTL [13]. Details of the crystal data are listed in Table 1.Selected bond lengths and angles are listed in Table 2

3.1 Syntheses and spectral analyses

Firstly, we synthesized the compound 1 according to reported mothed [9], when setting the power of microwave oven with 20%, the mole ratio n(Iron(III) chloride hexahydrate): n(3-hydroxy-2-naphthoic acid)=1:1.5, the yield was the highest 74% after 740s. The yield had been improved compared with Villemin’s report, and the product gives well-resolved HNMR spectra consistent with the report of Jingzhong Yi [10]
In the synthesis of compounds 2, we chose NaH as strong base which can seize the hydrogen at hydroxyl and carboxyl, and it was needed to add intermittently. If the NaH was added much more one time, the DMF would be deduced. If the NaH was added much less, the reaction time would be longer. The compound 2 structure was characterized by IR, H NMR, and 13C NMR. The BINOL derivative gives well-resolved HNMR spectra consistent with its structure.
3.2 Crystal structures of compound 2
The crystal structure of 2 shows in Figure1, in which the substitutes of naphthalene ring is far, its configuration is R-2, and the dihedral angle of two naphthyl rings is 87.44(9), nearly perpendicular.


Figure 1 the molecular structure of 2

In the crystal cell of 2, every two molecules form a small cuboid channel, four molecules form a bigger cuboid channel, and there are two naphthyl rings are parallel in two adjacent molecules (see Firgure 2 andFirgure 3).
Figure 2
crystal cell of 2 along a axis

Figure 3 crystal cell of 2 along b axis