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Synthesis of chiralliquid crystals
Low molecular mass liquid crystals are important components of liquid
crystal displays and mostly showing in all sorts of instrumentation including portable
computers and televisions.
It has been observed that low molecular mass liquid crystals display chiral nematic
phases over a broad temperature. The aim of this project was to study the synthetic
approaches outlined below would produce the desired low molecular mass monomers
and enable us to proceed in the synthesis of liquid crystal polymers.
Reaction scheme (1)
Boronic ester was synthesized (fig 1) in an inert atmosphere.
White crystalline product was obtained as the product.
IHNMR (CDCb) and mass spectrum was obtained for the product.
S 8.1(d,2ArH,a), 6.9(d,2ArH,b), 1.625(m,2H,d), 1.9(m,2H,e), 4.1 (q, 1H,f),
3.9(m,2H,g), 1. 15(s,3H,h), 1. 125(s,3H,l), O. 79(m, 1Hj), 1.39( d,3H,k), 1.3( d,3H,l)'
Resolution of isoprppyl peaks were not clear in the spectrum.
According to the mass spectrum most probable peak observed was 355.2.
Compound was melted at 1260
c.
Reaction scheme (2)
The byphenyl ether (fig 2) synthesized was a white crystalline solid and was analysed
By IH NMR spectrometer in OMSO.
o?.59(D,2ArH,a), 7.0(d,2ArH,b), 4.05(t,2H,c), 1.9(m,2H,d), l.8(m,2H,e),
3.47(m, IH,f), 5.5(t, IH,g).
According to the mass spectrum a strong peak of 390.3 could be observed.
The sample melted at 240°c.
Reaction scheme (3)
The product obtained in the scheme was a white solid (fig 3) and IH Nl\'lR (COCl,)
was recorded.
s 6.8(d,2ArH,a), 7.35(d,2ArH,b), 3.35(t,2H,c), 3.6(m, 1H,l)
According to the mass spectrum a strong peak of 371.3 was recorded.
The sample melted at 119.9
ll
c Reaction scheme (4)
The product synthesized (fig 4) was a white crystalline solid and IH NMR (CDCJ3)
was recorded.
5 7.45(d,2ArH,a), 7.35(d,2ArH,b), 7.4(d,2ArH,c), 6.85(d,2ArH,d), 3.95(t,2H,e),
1.85(q,2H,t), 2.2(q,2H,g), 3.625(m, 1H,h), and 3.35(t, 1H,l).
Reaction scheme (5)
Three crystalline products were synthesized.
An ether was synthesized (fig 5) using 4 bromo (1,11 biphenylj-l-ol which was a white
solid.
IH NMR (CDCh) was recorded.
57.45 (d,2ArH,a), 7.35(d,2ArH,b), 7.3(d,2ArH,c), 6.8(d,2ArH,d), 3.9(t,2H,e),
1.4(m,2H,t), 1.75(m,2H,g), 1.55(m,2H,h), 3.2(m,2H,l), 3.4(q,2Hj), 3.65(m, IH,k),
3.45(t,2H,!)
According to the mass spectrum strong peak of 393.4 was recorded and the sample
melted at 121.3
0
c.
The ether synthesized by using 4 bromo phenol (fig 6) was yellowish oil.
IH NMR (CDCh) recorded at 0 7.225(d,2i\r1I,a), 6.65(d,2i\rH,b), 3.475(t,2H,c),
1.65(m,2H,d), 1.35(m,2H,e), 3.6(m,2H,h), 3.6(q, 1H,I), and 3.375(m,2Hj).
The white crystalline dimmer (fig 7) synthesized by using 4,4/ dihydroxi biphenyl
was a heavy solid.
IH NMR (CDCh) was recorded at 0 7.325(d,2ArH,a), 6.8(d,2ArH,b), 3.45(t,2H,c),
1.7(m,2H,d), 3.58(m, 1H,I), 3.35(t,2Hj).
Strong peak of 471.5 was recorded in the mass spectrum and the compound melted at
141.2°c.
