52364-73-5Relevant academic research and scientific papers
Green chemistry approach to the synthesis of liquid crystalline materials
Kumar, Sandeep,Bisoyi, Hari Krishna,Pal, Santanu Kumar
, p. 287 - 294 (2008)
This article presents a simple, rapid, economic and environmentally acceptable microwave promoted "green chemistry" approach to the synthesis of some conventional and non-conventional liquid crystalline materials. Alkylation of 4'-hydroxy-4-biphenylcarbonitrile with various alkyl halides under microwave irradiation furnished alkoxycynobiphenyl-based calamitic liquid crystals in very high yield within one minute. Similarly, terminally-functionalized alkoxycyanobiphenyls and alkoxycyanobiphenyl dimers can also be prepared. Microwave irradiation of hexaalkoxytriphenylene in the presence of ionic liquids gives monohydroxy-pentaalkoxytriphenylene in about 30% yield. Novel imidazolium-based ionic liquid crystalline dimers can be easily prepared via quaternization reaction using microwaves. Classical reaction conditions failed to produce these dimers.
Unsymmetrical Aryl(2,4,6-trimethoxyphenyl)iodonium Salts: One-Pot Synthesis, Scope, Stability, and Synthetic Studies
Seidl, Thomas L.,Sundalam, Sunil K.,McCullough, Brennen,Stuart, David R.
, p. 1998 - 2009 (2016/03/15)
Diaryliodonium salts have recently attracted significant attention as metal-free-arylation reagents in organic synthesis, and efficient access to these salts is critical for advancement of their use in reaction discovery and development. The trimethoxybenzene-derived auxiliary is a promising component of unsymmetrical variants, yet access remains limited. Here, a one-pot synthesis of aryl(2,4,6-trimethoxyphenyl)iodonium salts from aryl iodides, m-CPBA, p-toluenesulfonic acid, and trimethoxybenzene is described. Optimization of the reaction conditions for this one-pot synthesis was enabled by the method of multivariate analysis. The reaction is fast (85% average), and has broad substrate scope (>25 examples) including elaborate aryl iodides. The utility of these reagents is demonstrated in moderate to high yielding arylation reactions with C-, N-, O-, and S-nucleophiles including the synthesis of a liquid crystal molecule.
Synthesis of new family of thiazoline and thiazole esters and investigation of their thermal properties
Schneider, Juliana M. F. M.,Sales, Eric S.,Livotto, Paolo R.,Schneider, Paulo H.,Merlo, Aloir A.
, p. 1493 - 1503 (2014/09/29)
A new family of thiazoline and thiazole esters has been synthesized and their thermal properties are presented and discussed. Thiazoline esters were obtained by cyclization reaction from 4-substituted benzenenitrile and amino acid L-cysteine followed by esterification reaction with selected alcohols and phenol. Subsequent oxidation step to transform thiazoline esters into thiazole esters was applied mediated by BrCCl3/DBU. The final thiazoline and thiazole esters are composed by terminal flexible hydrogenated alkyl chain from one side and to the other side by terminal segments of flexible alkyl chains (hydrogenated chain), (perfluoralkyl)alkyl chains (semifluorinated alkane) p-alkoxyphenyl chains. Some liquid crystals compounds for thiazoline and thiazole esters showed to be relevant. One of the thiazoline esters display a monotropic smectic A (SmA) mesophase while some thiazole esters show stable SmA mesophase. As expected semifluorinated alkane chain induce the formation of orthogonal mesophase by means of segregation effect.
Synthesis and study of new rod-like mesogens containing 2-aminothiophene unit
Puterová, Zita,Romiszewski, Jerzy,Mieczkowski, Jozef,Gorecka, Ewa
experimental part, p. 8172 - 8180 (2012/09/22)
We present a synthesis and mesomorphic properties of a new series of rod-like mesogens. All the compounds possess a substituted 2-aminothiophene unit as a main element in the structure attached to a stilbene moiety with a terminal alkyloxy chain (OR1, OR2 where R 1=CnH2n+1, R2=CmH 2m+1; n, m ranging from 6 to 12). The synthesis of alkyloxybiphenyl substituted 2-aminothiophenes was carried out by the Gewald reaction and the appropriate reaction conditions were investigated. The liquid-crystalline properties were studied via polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction. These materials exhibit nematic and/or smectic A phases. The influence of structural changes (variation in alkyloxy chain length and symmetry of the molecule) on mesogenic behaviour is discussed. Evaluation of UV-vis, fluorescent and electrochemical properties are also included.
Method for producing unsymmetrically substituted biphenyls
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, (2008/06/13)
PCT No. PCT/IB97/00266 Sec. 371 Date Sep. 29, 1998 Sec. 102(e) Date Sep. 29, 1998 PCT Filed Feb. 24, 1997 PCT Pub. No. WO97/30970 PCT Pub. Date Aug. 28, 1997The invention concerns a method for the production of unsymmetrically substituted cyanobiphenyls by the slow addition of an aryl Grignard compound to an optionally substituted bromobenzonitrile in the presence of a palladium complex catalyst.
Tilt Angle Variation as a Function of Chain Length and Temperature in the Smectic C Phases of p,Alkoxyphenyl-p,Alkoxybenzoates
Heinrich, B.,Guillon, D.
, p. 21 - 44 (2007/10/02)
The variation of the tilt angle with temperature in the smectic C phase has generally been shown to be non-existent or very slow for compounds or mixtures with the nematic-smectic C transition, while in the case of systems with the smectic A-smectic C transition, a relation between the steepness of this variation, near the transition, and the width of the smectic A domain has been observed.In this work, the variation of tilt angle in the smectic C phase is described for p-alkoxyphenyl-p-alkoxybenzoate homologous series, for which the evolution of polymorphism can be controlled systematically, by varying stepwise the length of the aliphatic chains, and for which large domains can be obtained for each type of phase sequence, nematic-, smectic A- and isotropic-smectic C.After completing the discussion made previously on the incidence of chain length on polymorphism, we confirm that the variation of tilt angle with temperature is slowest for compounds with intermediate chain lengths corresponding to the largest smectic A temperature range; this variation becomes continuously steeper when the smectic A domain becomes narrow.In addition, we show that the same description can be extended to the other types of phase sequences, by using the hypothesis of a virtual smectic A-smectic C transition above the observed nematic- or isotropic-smectic C transition.In fact, short chain lengths for homologues with a nematic/smectic C transition, or long chain lengths for homologues with an isotropic/smectic C transition, lead to an increase of the tilt angle at the phase transition and to a decrease of the amplitude of its variation with temperature; in our description, this behaviour corresponds to an increase of the temperature range between the real and virtual transitions.As a consequence, the homologues with very short and very long chain lengths show a quasi temperature-independent tilt angle, while the other homologues present a tilt angle variation similar to that observed for compounds exhibiting a smectic C/smectic A transition.This feature indicates that there is no need to distinguish between different types of smectic C phase.
SYNTHESIS OF 4-ALKOXY-4'-CYANOBIPHENYLS
Ruolene, Yu. I.,Adomenas, P. V.,Adomenene, O. K.,Denis, G. I.
, p. 1192 - 1195 (2007/10/02)
A preparative method was developed for the synthesis of liquid crystals of the 4-alkoxy-4'-cyanobiphenyl group.It involves the nitration of 4-cyanobiphenyl to 4-nitro-4'-cyanobiphenyl, reduction of the latter, diazotization of the obtained 4-amino-4'-cyanobiphenyl, and alkylation of the 4-hydroxy-4'-cyanobiphenyl formed during decomposition of the diazonium salt.
