The effect of Carbonyl Containing Substituents in the Terminal chains on Mesomorophic Progerties in Aromatic Esters and Thioesters, 2. Acyloxy Groups on the Phenolic End

Neubert, Mary E.; Wildman, Patricia J.; Zawaski, M. J.; Hanlon, Carol A.; Benyo, Theresa L.; Vries, Adriaan de

doi:10.1080/00268948708080217

Cited by 30 publications

(13 citation statements)

References 19 publications

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“…In previous structure-property relationship studies of the mesomorphic properties in the esters 2 and the thioesters 3, we found that increasing the flexibility of the terminal chain by inserting carbonyl-containing groups in different positions of the terminal chain tended to produce fewer mesophases, having shorter ranges and lower transition temperatures [1][2][3][4][5][6][7]. We also found that no additive effect occurred using different X and Y substituents [8].…”

Section: Introductionmentioning

confidence: 49%

“…In our experience, using only one equivalent of a reactant to obtain reaction on only one of two equally (or nearly so) reactive functional groups produces primarily the mono-product, but it is contaminated with small amounts of byproduct, starting material and some unknown higher molecular mass (polymer?) material making it very difficult to obtain a high purity monosubstituted product (see, for example, [2]). Although we were able to obtain some of the phenol 36 in this manner, the yields were too low to be practical for large quantities.…”

Section: Synthesismentioning

confidence: 99%

“…We previously prepared the acyloxy esters 34 by esterifying benzyloxy phenol 25 to obtain the protected acyloxyphenol 27, removing the benzyl group by hydrogenolysis to obtain the phenol 30 and then esterifying using the carbodiimide method [2]. The triple bond in the alkynyl analogues would, however, not survive the hydrogenolysis.…”

Section: Synthesismentioning

confidence: 99%

“…Preparation of the esters 4 and thioesters 5. All these compounds were synthesized using the carbodiimide method described earlier [2]. A reflux time of 2 h was sufficient to obtain a complete reaction for the esters 4 (n51) and 5 but the esters 4 with n52 required at least 6.5 h as determined by TLC monitoring of the reaction.…”

Section: Ethyl 4-heptynylbenzoate 15mentioning

confidence: 99%

“…The phenols 19 (n51, Y5R) [34], RO [35], CO 2 R[4], COR [1], OCO 2 R [2]; thiols 20 (Y5R) [33], RO [36] and acids 26 (n51, X5R) [24] were prepared using previously published methods. All other starting materials were commercially available and used without purification.…”

Section: Synthesismentioning

confidence: 99%

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The effect on mesomorphic properties of a triple bond in a terminal chain of 4,4′‐disubstituted phenyl benzoates and phenyl thiobenzoates

et al. 2005

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2005) The effect on mesomorphic properties of a triple bond in a terminal chain of 4,4′-disubstituted phenyl benzoates and phenyl thiobenzoates, Liquid Crystals, 32:2, 247-266,The effect of a triple bond in a terminal chain on the mesomorphic properties of rod-like mesogens was studied by replacing a straight alkyl chain with a terminal 1,2-alkynyl chain in some esters and thioesters of the type: or by incorporating the triple bond into an alkyl ester chain in esters and thioesters of the types:The triple bond should provide increased rigidity to the triple bond region but increased flexibility at the adjacent single bond. These should have opposite effects on the mesomorphic properties. The first compounds were synthesized by esterification of the appropriate alkynylbenzoic acids with various phenols or thiols using the carbodiimide method. Detailed syntheses are provided for the alkynylbenzoic acids. Preparation of the alkynyl ester compounds was by acylation of the precursor hydroxyl esters or thioesters using either the acid chloride or carbodiimide method. The synthesis of the phenolic or thiolic ester intermediates, usually using a protection group, is described. Mesomorphic properties of these new esters and thioesters were determined using hot stage polarizing microscopy and DSC and compared with those for the known parent compounds. Fewer mesophases having shorter temperature ranges and lower transition temperatures were usually observed. Some of the intermediate phenols or benzyl ethers were also studied. Long chain benzyloxy esters showed a nematic phase as did some of the hydroxy thioesters but no mesophases were observed in the hydroxy esters.

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