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S.V. Subrahmanyam et al. / Physica B 450 (2014) 173–184
pinacolato-diboran (17.51 mmol) and potassium acetate
chromatography using silica gel (230–400 mesh). Compound
was eluted in 40% DCM and petroleum ether. Purified com-
pound was re-crystalized from DCM/Methanol mixture to
procure dodecyl 4-(5-(4’-(decyloxy)biphenyl-4-yl)-1,2,4-oxa-
diazol-3-yl)benzoate (12) as white solid (0.2 g, 74.07%).
1H NMR (400 MHz, CDCl3)
(21.85 mmol). The reactants were stirred for 5 mt and
Nitrogen was purged out continuously for about 15 min.
The pd(dppf)Cl2 (0.21 mmol) was added and the resulting
reaction mixture was heated at 100 1C for about 16 h.
Reaction mixture was cooled and filtered through a pad of
Celite. The filtrate was concentrated. The residue was
purified by column chromatography by using Silica gel
(60–120) and product was eluted at 1–2% of EtoAc in
hexane.
The 1H NMR spectra exhibited by C12C10 (12) is presented in
Fig. 1.
∂ (ppm) 0.92 (t, J¼6.64 Hz, 6H), 1.29–1.39 (m, 29H) 1.44–
1.52 ( m, 4H), 1.78–1.85 (m, 2H), 4.03 (t, J¼6.56 Hz, 2H), 4.37
(t, J¼6.68 Hz, 2H), 7.03 (d, J¼8.76 Hz, 2H), 7.62 (d, J¼
8.72 Hz, 2H), 7.76 (d, J¼8.4 Hz, 2H), 8.20 (d, J¼8.4 Hz, 2H),
8.27 (d, J¼8.28 Hz, 4H)
4,4,5,5-tetramethyl-2-(4-(decyloxy)phenyl)-1,3,2-dioxabor-
olane, (9)
Yield 70.80%, 1H NMR (400 MHz, CDCl3): 7.87 (d, J¼8.58 Hz,
2H), 7.56 (d, J¼8.58 Hz, 2H), 4.09 (t, J¼6.70 Hz, 2H),
1.57–1.64 (m, 2H), 1.16–1.28 (m, 25H), 0.89 (t, J¼6.86 Hz, 3H).
Elemental analysis: calculated for C22H37BO3 (360.33) C
73.33, H 10.35 Found C 73.02, H 10.21.
13C NMR (CDCl3)
The 13C NMR spectra exhibited by C12C10 (12) is presented in
Fig. 2.
∂ 14.04, 22.61, 25.97, 28.63, 29.18, 29.22, 29.25, 29.27, 29.33,
29.46, 29.51, 29.56, 31.83, 65.44, 68.10, 114.96, 121.97, 127.04,
127.40, 128.21, 128.60, 129.94, 130.94, 131.66, 132.73, 145.28,
159.58, 165.98, 168.24, 175.95;
Step–iii
Procedure for the synthesis of Octyl 4-(5-(4’-(Decyloxy)-
biphenyl-4-yl)-1,2,4-oxadiazol-3-yl)benzoates, (10)
A biphenyl moiety is realized in one of the lateral moieties
of proposed BLC through the Suzuki [111] coupling reaction
as presented in the synthetic route of preparation for the
Elemental analysis: calculated for C43H58N2O4 (666.93) C
77.44, H 8.77, N 4.20 Found C 73.29, H 7.75, N 4.10.
C12C10. To a solution of Octyl 4-(5-(4-bromophenyl)-1,2,4-
oxadiazol-3-yl) benzoate, (0.091 mmol of 5), the 4,4,5,5-
tetramethyl-2-(4-(decyloxy)phenyl)-1,3,2-dioxaborolanes
(1.36 mmol of 9) is added and stirred by adding 1,2-DME
(10 Vol) and aqueous Na2CO3 (2.00 mmol) solution. Nitro-
gen was purged out for 15 min, followed by the addition of
Pd (pph3)2Cl2 (0.018 mmol). The reaction was refluxed for
16 h under Nitrogen atmosphere. Reaction mixture was
concentrated and residue was taken in Dichloromethane.
It was given a wash with water and brine solution. The
product (10) was dried over anhydrous sodium sulfate and
concentrated. Crude product was purified by column chro-
matography (SiO2 230–400) and the product was eluted in
40% Dichloromethane mixed with petroleum ether. The
product (10) obtained was re-crystallized from dichloro
methane and methanol mixture. The synthetic yield is
observed to be a color less (white) solid.
2.2. Experimental techniques for the LC phase characterization
1H NMR study of C12C10 is carried out with a Bruker 400 MHz
spectrometer using deuterated Chloroform as solvent and Tetra-
methyl Silane as internal standard (procured from Sigma-Aldrich).
Polarized Optical Microscopy (POM) is carried out using an SD-
Tech instrument in conjunction with an Instec HCS-402 Hot stage
in conjunction with an STC-200 Temperature Controller which
Octyl 4-[(5-(4’-(decyloxy)biphenyl-4-yl)-1,2,4-oxadiazol-3-yl)]
benzoate, (10)
Yield 41.27%, 1H NMR 400 MHz, CDCl3: ∂ (ppm) 8.25–8.29 (m,
4H), 8.19 (d, J¼8.52 Hz, 2H), 7.75 (d, J¼8.48 Hz, 2H), 7.61 (d,
J¼8.72 Hz, 2H), 7.02 (d, J¼8.76 Hz, 2H), 4.36 (t, J¼6.64 Hz,
2H), 4.02 (t, J¼6.56 Hz, 2H), 1.79–1.84 (m, 4H), 1.27–1.56 (m,
31H), 0.89 (quintet, 6H).
Fig. 1. 1H NMR spectra for C12C10
.
Elemental analysis: calculated for C39H50N2O4 (610.82) C
76.69, H 8.25, N 4.59 Found C 76.34, H 7.97, N 4.35.
Step–iv
Synthesis of Dodecyl 4-(5-(4’-(decyloxy)biphenyl-4-yl)-
1,2,4-oxadiazol-3-yl)benzoate (12)
To a stirred solution of octyl 4-(5-(4’-(decyloxy)biphenyl-4-yl)-
1,2,4-oxadiazol-3-yl)benzoate 10 (0.25 g, 0.409 mmol), Metha-
nol, water and THF was added in 1:1:2 (40 vol) ratio along
with KOH (0.045 g, 0.818 mmol) at 0 1C and stirred. The
reaction mixture was stirred for 16 h. THF was removed and
the reaction mixture was cooled to 0 1C. Reaction mixture was
acidified with 1.5 N HCl solution. Solid separated was filtered
and given water wash and dried. The residue was taken in dry
dichloromethane (10 vol) and was added to DCC (0.126 g,
0.614 mmol) and DMAP (0.075 g, 0.614 mmol) under Nitrogen
atmosphere, followed by the addition of Dodecanol (11),
(0.114 g, 0.614 mmol). The reaction mixture was stirred for
16 h. Solid separated was filtered. Filtrate was concentrated to
get the crude product. Crude product was purified by column
Fig. 2. 13C NMR spectra for C12C10
.