Synthesis and Structure Determination of 2-Cyano-3-(1-phenyl- 3-(thiophen-2-yl)-1 H -pyrazol-4-yl)acrylamide

966-11469-3778; Fax: +966-11469-3536 Abstract: 2-Cyano-3-(1-phenyl-3-(thiophen-2-yl)-1 H -pyrazol-4-yl)acrylamide ( 3 ) was synthesized in 90% yield from condensation of equimolar equivalents of 1-phenyl-3-(thiophen-2-yl)-1 H -pyrazole-4- carbaldehyde ( 1 ) and 2-cyanoacetamide ( 2 ) in boiling ethanol under basic condition for 45 min. The structure of 3 was determined using NMR spectroscopy and single crystal X-ray diffraction.


Introduction
Compounds containing the acrylamide residue are potentially biologically active as well as acting as precursors in many organic syntheses [1][2][3][4].Pyrazoles are also important heterocycles with promise for medicinal applications as a result of their wide range of biological activities [5,6].In addition, heterocycles containing thiophene ring systems have many latent applications [7][8][9].The synthesis of heterocycles containing both pyrazole and thiophene moieties is therefore an intriguing prospect.

NMR Spectroscopy
The 1 H NMR spectrum of 3 showed the presence of 12 protons with the NH 2 protons appearing as an exchangeable singlet at low field (δ = 9.11 ppm).The pyrazole proton appears as a singlet at 8.16 ppm.The 1 H NMR spectrum showed the presence of a doublet (two protons) and two triplets (one and two protons) corresponding to the five protons of the phenyl ring.The 13 C NMR spectrum of 3 showed the expected signals for all carbons with the carbonyl (C=O) and nitrile (C≡N) carbons appearing at 163.0 and 117.3 ppm, respectively.The NMR spectra for 3 are included in the supplementary materials.
The conformations of the two independent molecules are very similar in the crystal, as shown by the twist angles between adjacent groups.The angles between the groups are: A1/B1 = 18.9 ( 2

General
The melting point of 3 was determined using an Electrothermal melting point apparatus.The IR spectrum of 3 was recorded on a JASCO FT/IR-4600 spectrometer.The NMR spectra of 3 were measured on a JEOLNMR 500 MHz spectrometer at 500 MHz for the 1 H and 125 MHz for the 13 C NMR.The coupling constant (J) and the chemical shift (δ) are reported in Hz and ppm, respectively.Compound 1 was prepared based on a literature procedure [28].

Synthesis of 3
A mixture of 1 (0.51 g, 2.0 mmol) and 2 (0.17 g, 2.0 mmol) in ethanol (10 mL) containing piperidine (0.17 g, 2.0 mmol) was refluxed for 45 min.The mixture was cooled to room temperature and the solid formed was filtered, washed with ethanol, and dried.The crude product was recrystallized from dimethylformamide to give pale yellow crystals of δ

Figure 1 .
Figure 1.Ortep representation of the asymmetric unit of 3 showing 50% probability atomic displacement parameters.

Figure 2 .
Figure 2. Crystal structure packing viewed down the b axis with hydrogen bonding contacts shown as red dashed lines.