Changing and challenging times for service crystallography

The preparation of [NMC][B5O6(OH)4] {NMC = 2-MeC3N2H4 (3),1-MeC3N2H4 (4), 4-MeC3N2H4 (5), 1,2-Me2C3N2H3 (6), 1,2,3-Me3C3N2H2 (7), 1-EtC3N2H4 (8), 2-EtC3N2H4 (9), 2-Et-4-MeC3N2H3 (10) 1-Et-3-MeC3N2H3 (11) and 2-i PrC3N2H4 (12)} salts are reported. Compounds were characterized by spectroscopy (NMR and IR) and by single crystal XRD (6, 7, 9, 10, 12) studies. All structures show extensive H-bonded networks and 7 displays the first example of reciprocal paired  anion-anion interactions.These are facilitated by the pentaborate boroxole rings being significantly distorted

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“…We thank the EPSRC for use of the X-ray crystallographic service (Southampton) [41]. We thank the reviewers for their constructive comments.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Synthesis and X-ray structural studies of pentaborate(1−) salts containing substituted imidazolium cations

2014

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“…Critically,w ew ere able to confirm that the C À Ha ctivation hado ccurred in the ortho-position as anticipatedf rom ac helation controlled process by crystal-structure determinations of an umber of products( vide infra) [8] (Figure 1). We synthesised as eries of fluorinated aromatics 2 due to the advantageousrole of fluorine in medicinalc hemistry.…”

Section: Resultsmentioning

confidence: 65%

Late Stage CH Activation of a Privileged Scaffold; Synthesis of a Library of Benzodiazepines

Khan

Felix²,

Kemmitt

et al. 2016

Adv Synth Catal

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This paper is dedicated to Professor MichelP feffer (ULP,S trasbourg) for his contributions to C À Ha ctivation and palladacycle chemistry. Abstract: Al ibrary of over twenty 5-(2-arylphenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-ones has been formed by am icrowave-mediated late-stage palladium-catalysed arylation of 1,4-benzodiazepines using diaryliodonium salts. This can also be applied to nordazepam (7-chloro-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one), the active metabolite of diazepam, and subsequent N-alkylation and/or H/D exchangea llowsf urther diversification towards elaborated pharmaceuticals andt heir3 ,3'-deuterated analogues.

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“…The theophylline:acetamide cocrystal crystal structure was collected and solved by the EPSRC UK National Crystallographic Service at the University of Southampton 44 on a Bruker Nonius Instrument with KappaCCD area detector (φ scans and ω scans to fill asymmetric unit sphere).…”

Section: Methodsmentioning

confidence: 99%

Investigation of an Amide-Pseudo Amide Hydrogen Bonding Motif within a Series of Theophylline:Amide Cocrystals

Eddleston

Arhangelskis

Fábián

et al. 2015

Crystal Growth & Design

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The pharmaceutically active compound theophylline (T) was cocrystallized with the amides formamide (1), acetamide (2), N-methylformamide (3), N,N-dimethylformamide (4), benzamide (5), and pyrazinamide (6), with systems T:1, T:5, and T:6 displaying polymorphic behavior. The cocrystals with formamide (T:1), acetamide (T:2), and benzamide (T:5), and one polymorph of the cocrystal with pyrazinamide (T:6-I), contain an R 2 2 (9) hydrogen bonding motif between the amide cocrystal formers and the HN−C−CO moiety of the theophylline molecule (an amide-pseudo amide synthon). This motif was, however, absent from the other polymorph of the pyrazinamide cocrystal (T:6-II) and also from the N-methylformamide cocrystal (T:3) (and is not possible in the N,N-dimethylformamide cocrystal (T:4)). These observations are rationalized using hydrogen bond propensity calculations, although limitations of using such calculations for predicting cocrystallization are noted. The amide-pseudo amide synthon is favored when theophylline cocrystallizes with both primary amides and with secondary amides which are locked in a cis configuration. On heating, all cocrystals were found to dissociate before melting due to loss of the amide, making stability to dissociation a more meaningful measure of cocrystal stability than melting point for these systems. On dissociation of the cocrystals, theophylline typically crystallizes as the commonly observed polymorph Form II. In the case of the acetamide cocrystal (T:2), however, the rarely observed metastable polymorph, Form V, crystallizes concomitantly with Form II suggesting that cocrystal dissociation on heating could be a strategy for identifying novel polymorphic forms of compounds.

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Changing and challenging times for service crystallography

Cited by 445 publications

References 33 publications

Synthesis and X-ray structural studies of pentaborate(1−) salts containing substituted imidazolium cations

Synthesis and X-ray structural studies of pentaborate(1−) salts containing substituted imidazolium cations

Late Stage CH Activation of a Privileged Scaffold; Synthesis of a Library of Benzodiazepines

Investigation of an Amide-Pseudo Amide Hydrogen Bonding Motif within a Series of Theophylline:Amide Cocrystals

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