Synthesis and Radical Copolymerization of Novel Phenyl-Disubstituted Propyl Cyanoacrylates
Christopher Savittieri R, Shechinah Tinsley M, Andrew Diehn J, Fatema Hai, Kara Humanski E, Eric Kempke J, Benjamin Killam Y, Jimmy Kozeny, Evana Makhoul W, Molly Obert C, Anthony Parisi C, Victoria Parrilli C and Gregory Kharas B*
Department of Chemistry, DePaul University, USA
Submission: May 06, 2019; Published: May 13, 2019
*Corresponding author: Gregory Kharas B, Department of Chemistry, DePaul University, Chicago, IL, USA
How to cite this article: Christopher Savittieri R, Shechinah Tinsley M, Andrew Diehn J, Fatema Hai, Kara Humanski E, Gregory Kharas B, et al. Synthesis and Radical Copolymerization of Novel Phenyl-Disubstituted Propyl Cyanoacrylates. Academ J Polym Sci. 2019; 2(5): 555597.DOI: 10.19080/AJOP.2019.02.555597
Abstract
Novel phenyl-disubstituted propyl 3-(R-phenyl)-2-cyanoacrylates, RPhCH=C(CN)CO2C3H7 (where R is 2-fluoro-5-methyl, 3-iodo-4-methoxy, 5-iodo-2-methoxy, 3,5-dichloro, 3,4-difluoro, 3,5-difluoro, 2-chloro-4-fluoro, 2-chloro-6-fluoro, 3-chloro-2-fluoro, and 3-chloro-4-fluoro) were prepared using condensation of substituted benzoic aldehydes and propyl ester of cyanoacetic acid. The ethynyl benzene copolymerization of novel cyanoacrylates was conducted in solution with radical initiation at 70 C. Nitrogen analysis, 1H & 13C NMR was used to analyze composition and the structure. Thermal behavior of the copolymers was analyzed by DSC and TGA.
Keywords: Radical copolymerization; Styrene copolymers; Trisubstituted ethylene’s; Cyanoacrylates
Introduction
Ring–functionalized trisubstituted ethylene’s (TSE), esters of 3-phenyl-2-cyanoacrylates, R1PhCH=C(CN) CO2R2 continue to attract attention as compounds with interesting properties and as comonomers for modification of commercial polymers. 3,4-Difluorophenyl substituted methyl 3-phenyl-2-cyanoacrylate was used in synthesis and studies of histamine H2 agonistic activity [1]. Ethyl 3-phenyl-2-cyanoacrylate was used in studies of stereoselective cascade assembling of (1R*,2S*)-1-cyano-5,7-dialkyl-4,6,8-trioxo-2-aryl-5,7-diazaspiro[2.5]octane-1-carboxylates [2] and analgesic activity of 6-fluoroindan-1-carboxylic acid [3]. Alkyl 2-cyanoacrylates are a family of vinyl monomers renowned for their high reactivity, instant adhesive properties, and wide-ranging applications [4].
We have reported synthesis and ethynylbenzene copolymerization of similar ring-substituted methyl [5], ethyl [6], & butyl 3-phenyl-2-cyanoacrylates [7]. With the objective to design novel structures, that could serve as a spring board for further development of novel materials with new properties and applications, we have prepared halogen ring-disubstituted propyl 3-phenyl-2-cyanoacrylate (PPCA), RPhCH=C(CN)CO2C3H7sub>, where R is 2-fluoro-5-methyl, 3-iodo-4-methoxy, 5-iodo-2-methoxy, 3,5-dichloro, 3,4-difluoro, 3,5-difluoro, 2-chloro-4-fluoro, 2-chloro-6-fluoro, 3-chloro-2-fluoro, and 3-chloro-4-fluoro, and copolymerize them with ethynylbenzene. To the best of our knowledge, there have been no reports on either synthesis of these propyl phenyl cyanoacrylates, nor their copolymerization with ethynylbenzene.
Experimental
All benzoic aldehydes, propyl cyanoacetate, piperidine, ethynylbenzene, 1,1’-azobiscyclohexanecarbonitrile, (ABCN), and toluene supplied from Sigma-Aldrich Co., were used as received. The melting points and Tg, were measured with TA Model Q10 DSC. The thermal stability of the copolymers was measured by TGA TA Model Q50 from ambient temperature to 800 ºC at 20 ºC/min. The MW of the copolymers was determined by GPC using an Altech 426 HPLC pump at an elution rate of 1.0mL/min; Phenogel 5μ Linear column at 25 ºC and Viscotek 302 detector. 1H & 13C NMR spectra were obtained on 10-25% (w/v) monomer or polymer solutions in CDCl3sub> at ambient temperature using Avance 300MHz spectrometer. Elemental analyses were performed by Midwest Microlab, LLC (IN).
Results and Discussion
PPCA synthesis
The ring-substituted propyl 3-phenyl-2-cyanoacrylates (PPCA) were synthesized by Knoevenagel condensation [8] of a ring-substituted benzoic aldehyde with propyl cyanoacetate, catalyzed by base, piperidine (1).
Where R is 2-fluoro-5-methyl, 3-iodo-4-methoxy, 5-iodo- 2-methoxy, 3,5-dichloro, 3,4-difluoro, 3,5-difluoro, 2-chloro- 4-fluoro, 2-chloro-6-fluoro, 3-chloro-2-fluoro, & 3-chloro-4- fluoro. The preparation procedure was essentially the same for all the monomers. In a typical synthesis, equimolar amounts of propyl cyanoacetate and an appropriate ring-substituted benzoic aldehyde were mixed in equimolar ratio in a 20mL vial. A few drops of piperidine were added with stirring. The product of the reaction was isolated by filtration and purified by crystallization from 2-propanol. The condensation reaction proceeded smoothly, yielding products, which were purified by conventional techniques.