1-[4-(Difluoromethoxy)phenyl]-N-(2,3-dimethylphenyl)-1H-1,2,4-triazole-3-carboxamide

In the mol­ecule of the title compound, C18H16F2N4O2, the 1,2,4-triazole ring forms dihedral angles of 3.6 (2) and 14.9 (6)° with the 4-difluoro­meth­oxy-substituted benzene ring and the 2,3-dimethyl-substituted benzene ring, respectively. The OCHF2 group is twisted away from the plane of the benzene ring, as shown by the C—O—C—C torsion angle of 145.8 (2)°. The conformation is stabilized by an inter­molecular N—H⋯N hydrogen bond. In the crystal, short C—H⋯O inter­actions lead to chains of mol­ecules

Induced in-source fragmentation pattern of certain novel (<it>1Z,2E</it>)-<it>N</it>-(aryl)propanehydrazonoyl chlorides by electrospray mass spectrometry (ESI-MS/MS)

<p>Abstract</p> <p>Background</p> <p>Collision induced dissociation (CID) in the triple quadrupole mass spectrometer system (QQQ) typically yields more abundant fragment ions than those produced with resonance excitation in the presence of helium gas in the ion trap mass spectrometer system (IT). Detailed product ion spectra can be obtained from one stage MS² scan using the QQQ. In contrast, generating the same number of fragment ions in the ion trap requires multiple stages of fragmentation (MSⁿ) using CID via in-trap resonance excitation with the associated time penalties and drop in sensitivity.</p> <p>Results</p> <p>The use of in-source fragmentation with electrospray ionization (ESI) followed by product ion scan (MS²) in a triple quadrupole mass spectrometer system, was demonstrated. This process enhances the qualitative power of tandem mass spectrometry to simulate the MS³ of ion trap for a comprehensive study of fragmentation mechanisms. A five pharmacologically significant (<it>1Z</it>, <it>2E</it>)-<it>N</it>-arylpropanehydrazonoyl chlorides <b>(3a-e)</b> were chosen as model compounds for this study. In this work, detailed fragmentation pathways were elucidated by further dissociation of each fragment ion in the ion spectrum, essentially, by incorporating fragmentor voltage induced dissociation (in-source fragmentation) and isolation of fragments in a quadrupole cell Q1. Subsequently, CID occurs in cell, Q2, and fragment ions are analyzed in Q3 operated in product ion mode this process can be referred to as pseudo-MS³ scan mode.</p> <p>Conclusions</p> <p>This approach allowed unambiguous assignment of all fragment ions using tandem mass spectrometer and provided adequate sensitivity and selectivity. It is beneficial for structure determination of unknown trace components. The data presented in this paper provide useful information on the effect of different substituents on the ionization/fragmentation processes and can be used in the characterization of this important class of compounds.</p