1,3-Oxazepane-4,7-Diones Compounds: 1Hand 13CNMR High-Resolution Spectroscopy (1D and 2D)

“Oxazepine” refers to any seven-membered ring containing an oxygen and nitrogen atom. The 1,3-oxazepine is a branch of many types of the heterocyclic oxazepine [1–7]. The core structure of 1,3-oxazepane-4,7diones consists of a sevenmemebred ring along with two carbonyl group. Over the years, the syntheses of oxazepine derivatives have been investigated and documented. The result is important of heterocyclic compounds having significant biological uses [8– 13]. Recently, we prepared a variety of 1,3-oxazepinediones in order to study the spectroscopic and liquid crystal properties [14]. In this paper, we present the structural elucidation by 1D and 2D NMR experiments of 3-alkyl- 2-(3-hydroxyphenyl)-1,3-oxazepane-4,7-diones with general formula(HOC6H4)CONCnH2n+1CH-CH(CO)2 (where n = 2, 4, 6, 8, 10, 12, 14, 16, and 18). Here, the hydroxyphenyl and the terminal alkyl chain are attached to the oxazepane ring

New mesogenic compounds possessing a biphenyl ester and ether moiety comprising 1,3-dimethylbarbituric acid: synthesis, characterisation and mesomorphic studies

New substituted derivatives of 5-vinyl-1,3-dimethylbarbituric acid were synthesised and evaluated for liquid crystal properties. Two sets of molecules were prepared. One end of all the molecules possesses the 1,3-dimethylbarbituric core. The first set comprises biphenyl ethers, 4a–n and the second set biphenyl esters, 5a–g. Liquid crystalline properties were investigated by POM and DSC techniques. All the compounds exhibited enantiotropic smectic A and nematic mesophases. The LC properties were found to depend on the spacer and terminal alkoxy- chain and alkoxy- ester moiety of the molecules. Smaller alkyl chain members showed a smectic phase, while higher alkyl chain members showed a nematic phase

Sintesis Dan Sifat Hablur Cecair Bagi Beberapa Terbitan Chalcone Dan Hasil Semulajadi Yang Berkaitan

Sintesis dan kaj ian secara komprehensif atas siri terbitan calkon seperti 1fenil- 3-(4-hidroksifenil)-2-propen-I-on dan 3-fenil-I-(4"-hidroksifenil)-2-propenI- on telah dijalankan buat pertama kalinya di Makmal Penyelidikan Hablur Cecair, Pusat Pengajian Sains Kimia. Synthesis and comprehensive study upon series of chalcone derivatives 1phenyl- 3-(4-hydroxyphenyl)-2-propen-1-one and 3-phenyl-1-(4"-hydroxyphenyl)2- propen-1-one have been carried out for the first time in the Liquid Crystal Research Laboratory, School of Chemical Sciences

Synthesis and mesomorphic properties of new heterocyclic liquidcrystals with Central Ester–Chalcone linkages

A series of new calamitic liquid crystals, 4-[3-(pyridin-4-yl)prop-2-enoyl]phenyl 4-alkyloxybenzoates, comprising a pyridyl core,ester–chalcone central linkage and terminal alkyloxy chain were synthesized and characterized. This series consists of four membersthat differ by the length of the alkyloxy chain (CnH2n+1O , where n = 10, 12, 14, 16). The structures of the title compounds wereelucidated using spectroscopic and spectrometric techniques, such as FT-IR, NMR (1H and13C) and EI-MS. The mesomorphicproperties were studied using differential scanning calorimetry and optical polarizing microscopy. The decyloxy-containing com-pound was found to be non-mesogenic, whilst the compounds containing n-dodecyloxy to n-hexadecyloxy chains exhibited anenantiotropic smectic A phase with a fan-shaped texture. From the structure–property relationship study, it was proposed that thenumber of carbons in the alkyloxy chain must be at least 12 (n ≥ 12) to generate the smectic phase in the corresponding substitutedArCOOArCOCH CHC5H4N compounds

Synthesis and Liquid Crystalline Properties of New Schiff Bases N-[4-(4–n-Alkanyloxybenzoyloxy)benzylidene]-4-cyano-, 4-Hydroxy-, Thio-4-Nitroanilines

Abstract: Series of elongated Schiff base esters containing three aromatic rings with hexadecanoyl 2 moiety as one of the terminal carbon chain and various substituents R (R = CN, OH, SH, and NO ) at the other end of molecule have been isolated, and their structures were proposed via physical measurement. The mesomorphic properties of these compounds were investigated via differential scanning calometry and polarizing optical microscopy. The thermal data indicate that all of these compounds exhibit mesomorphic properties except compound with R = SH. Although compounds with 2 R = OH and NO show nematic phases, compound containing cyano substituent are smectogenic in nature