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Updated: Jun 1, 2026
05:07
Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
Published on: June 23, 2019
5,6-Di-2-thienyl-2,3-dihydro-pyrazine
Madhukar Hemamalini1, Hoong-Kun Fun
1X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
Summary
Researchers synthesized a novel compound, C(12)H(10)N(2)S(2), revealing a unique dihedral angle between thiophene rings. Intermolecular hydrogen bonds and pi-interactions stabilize its crystal structure.
Area of Science:
- Crystallography
- Organic Chemistry
- Materials Science
Background:
- The synthesis and structural characterization of novel organic compounds are crucial for advancing materials science.
- Thiophene-based compounds are of interest due to their diverse electronic and structural properties.
Purpose of the Study:
- To synthesize and elucidate the crystal structure of a new compound formed from 2,2'-thenil and ethylenediamine.
- To investigate the intermolecular interactions governing the compound's solid-state structure.
Main Methods:
- Chemical synthesis involving the reaction of 2,2'-thenil and ethylenediamine.
- Single-crystal X-ray diffraction analysis to determine the molecular and crystal structure.
Main Results:
- The title compound, C(12)H(10)N(2)S(2), was successfully synthesized.
- X-ray crystallography revealed a dihedral angle of 66.33(9)° between the two thiophene rings.
- Intermolecular C-H⋯N hydrogen bonds form infinite chains, and weak C-H⋯π interactions contribute to structural stabilization.
Conclusions:
- The study provides a detailed structural analysis of a novel thiophene derivative.
- The identified hydrogen bonding and pi-interactions offer insights into crystal engineering and molecular assembly.
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Heterocyclic aromatic compounds are cyclic compounds that are aromatic and have one or more heteroatoms—atoms other than carbon, in the ring. Depending upon the number of atoms present in the ring, they can be either five or six-membered. Examples of five-membered heterocyclic aromatic compounds include pyrrole, furan, thiophene, and imidazole. Pyrrole consists of one nitrogen atom having one lone pair of electrons. Furan and thiophene have one oxygen and one sulfur heteroatom, respectively.
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Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
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Removing one hydrogen from the intervening CH2 group with both...
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