Synthesis and Characterization of Heterocyclic Chalcones Containing Halogenated Thiophenes

Abstract

Heterocyclic chalcones containing halogenated thiophenes were synthesized. The first step was to synthesize 3-acetyl-2,5-dichlorothiophene and 2-acetyl-5-chlorothiophene as heterocyclic ketones by using Friedel-Crafts acylation. The ketones were then used to synthesize thiophene chalcones through Claisen-Schmidt reaction with the respective heterocyclic aldehydes such as 5-bromothiophene-2-carbaldehyde, 3-methyl-2-thiophene carboxaldehyde and 2-thiophene carboxaldehyde with 3-acetyl-2,5-dichlorothiophene or 2-acetyl-5-chlorothiophene in presence of basic medium, sodium hydroxide to form the corresponding chalcones. Structures of the synthetic compounds were confirmed by IR, MS, 1H and 13C NMR spectral data.

Unexpected formation of a co-crystal containing the chalcone (E)-1-(5-chlorothiophen-2-yl)-3-(3-methylthiophen-2-yl)prop-2-en-1-one and the keto–enol tautomer (Z)-1-(5-chlorothiophen-2-yl)-3-(3-methylthiophen-2-yl)prop-1-en-1-ol

“…On the other hand, thiophene derivatives display a wide range of biological activities such as antimicrobial (Mishra et al, 2012), antiallergic (Gillespie et al, 1985), anti-inflammatory (Molvi et al, 2007), antioxidant and antitumor agents (Jarak et al, 2005). Combining thiophenes and chalcones could result in compounds with interesting new structures and properties: Al-Maqtari et al (2015) reported the synthesis of thiophenechalcones containing two thiophene rings and their antimicrobial and anticancer activities. One of their reported structures is (E)-1-(5-chlorothiophen-2-yl)-3-(3-methylthiophen-2-yl)prop-2-en-1-one.…”

“…The synthesis was carried out using a reported method (Al-Maqtari et al, 2015). Crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation, at room temperature, of a solution in ethanol.…”

X-Ray Powder Diffraction Data for a New Thiophene Chalcone Obtained by a Claisen-Schmidt Reaction

“…The title compound was synthesized by the Claisen-Schmidt condensation method (Kumar et al, 2013b) (Figure 1) using a methodology recently reported (Al-Maqtari et al, 2015). A mixture of 3-acetyl-2,5-dichlorothiophene (1) (0.03 mmol) and 5-bromo-2thiophenecarboxaldehyde (2) (0.03 mmol) was dissolved in methanol (25mL).…”

“…With the interested in the structural characterization of compounds with possible pharmacological activity (Vizcaya et al, 2012;Gonzalez et al, 2012;Delgado et al, 2015;Delgado et al, 2016;Delgado et al, 2018a;2018b), the present work is focused on report the X-ray powder diffraction data for the new heterocyclic chalcone (E)-3-(5-bromo thiophen-2yl)-1-(2,5-dichlorothiophen-3-yl)-2-propen-1-one, which was prepared among a series of thiophene derivative chalcones as potential anti-cancer and anti-microbial agents (Al-Maqtari et al, 2015). Its crystal structure was recently reported and crystallizes in the monoclinic space group P2 1 /n (Delgado et al, 2018b).…”

X-Ray Powder Diffraction Data for a New Pirazoline Compound

“…The 5-membered heterocyclic compounds type pyrazolines are important agents in medicinal chemistry as a promising scaffold for structural modification and drug development studies due to their wide range of biological activities such as anticancer, antifungal, antibacterial, antidepressant, anticonvulsant, antitubercular, antioxidant, antileishmanial and anti-inflammatory activity (Kumar et al, 2013;Deng et al, 2012;Ӧzdemir et al, 2007;Rani et al, 2011;Insuasty et al, 2012;Montoya et al, 2014;Moreno et al, 2018). Acetylated pyrazolines have been found to be more active than the non-acetylated pyrazolines (Khalil et al, 2012;Monga et al, (2014); Al-Maqtari et al, 2015). It has been reported that the introduction of the acetyl group at first position enhances the molluscicidal activity as well as increases the stability of pyrazolines (Mishriky et al, 1996).…”