Unsymmetrically substituted furoxans. VII. A <sup>13</sup>C NMR study of a series of isomeric pairs of furoxans and the structure of the two isomeric chloro‐phenyl‐furoxans

Calvino, R.; Fruttero, Roberta; Gasco, Alberto; Mortarini, V.; Aime, Silvio

doi:10.1002/jhet.5570190243

Cited by 29 publications

(16 citation statements)

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“…Monosubstituted furazans [364], phenylfurazans [365], azoxyfurazans [366], and hydroxy-, alkoxy-and phenoxyfurazans [367] have been studied by NMR spectroscopy. Additive schemes have been developed and spectrum-structure correlations have been elucidated.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

Oxadiazoles

Romeo¹,

Chiacchio²

2011

Modern Heterocyclic Chemistry

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Section: Nmr Spectroscopymentioning

confidence: 99%

Oxadiazoles

Romeo¹,

Chiacchio²

2011

Modern Heterocyclic Chemistry

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“…see Table 3 in the Exper. Part) [20]. The structural assignments were confirmed by an X-ray crystal-structure analysis of the isomer 6b (Fig.…”

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confidence: 84%

The Furoxan System: Design of Selective Nitric Oxide (NO) Donor Inhibitors of COX-2 Endowed with Anti-Aggregatory and Vasodilating Activities

Grosso¹,

Boschi²,

Lazzarato³

et al. 2005

C&B

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Several NO donor 3,4-diphenylfuroxan (= 3,4-diphenyl-1,2,5-oxadiazole 2-oxide) derivatives were synthesized and tested for their COX-inhibiting activities. The products were found to be selective COX-2 inhibitors, similar to the structurally related furazans (3,4-diphenyl-1,2,5-oxadiazole), devoid of the NO release property. This behavior was confirmed by a molecular-docking study. The NO-dependent platelet anti-aggregatory and vasodilating activities of the new furoxans 5-7 were studied in vitro. These properties can be modulated by inserting an appropriate spacer between the 4-phenyl group and the furoxan ring, giving rise to new, selective COX-2 furoxan derivatives endowed with anti-aggregatory and vasodilating activities, and with potentially reduced cardiotoxicities.

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“…Crystals synthesized by Calvino et al (1982) from ethanol-water as transparent, colourless, squat prisms. Dm not determined.…”

Section: Data Collectionmentioning

confidence: 99%

“…Following the convention of regarding the N atom of the N-oxide function as the 2-position, Calvino, Gasco, Fruttero, Mortarini & Aime (1982) assigned the lower-melting isomer of the title pair as 3-phenylfuroxan, (1A), and the higher-melting isomer as 4-phenylfuroxan, (1B), on the basis of spectroscopic studies (13C NMR spectroscopy). The X-ray analysis confirmed the assignment.…”

Section: Introductionmentioning

confidence: 99%

Structural and molecular-orbital study of the furoxan ring. Structures of 3-phenylfuroxan and 4-phenylfuroxan and comparison with related structures

Calleri¹,

Ranghino²,

Ugliengo³

et al. 1986

Acta Crystallogr Sect B

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On the other hand, the method with symmetryadapted functions always requires more parameters. Its use is mainly interesting when the molecular orientations are not really localized, because the librational anharmonicity is then taken into account. However, two problems may occur in this method which is available only for rigid molecules:(i) When the translational amplitude is very important, as for HMDS, the Bragg reflections are only observable for small values, even if the molecular orientations are localized. It is then very difficult to deduce from the refinements the orientational molecular probability.(ii) When the functions adapted to the molecular symmetry have negligible values for the atoms of the external shells of the molecule, the corresponding A,,m, terms are only related to the internal shells and are not then easily refinable. In this case, occurring in HME, the molecular orientational probability deduced from the refinements is less localized than in reality, mainly at low temperature.However, the comparative use of these two different methods gives a very accurate view of the long-range order in plastic crystals.We would like to thank Professors Fouret and Lefebvre for their interest in this work and Drs Sauvajol, Gharby and Gors for interesting discussions. AbstractAb initio and CNDO/2 molecular-orbital calculations have been performed for the positional isomer pairs of phenylfuroxan, methylfuroxancarboxamide, isopropyl N-(methylfuroxanyl)carbamate, and chloro(phenyl)furoxan, for the molecules of dimethylfuroxan, diphenylfuroxan, and furazan and for an idealized unsubstituted furoxan molecule. The furoxan ring appears to be electron-overcrowded, in * Furoxan is furazan N-oxide. t To whom correspondence should be addressed. particular in furoxan itself, which has not been synthesized so far. This excess of charge is released toward the substituents in the derivatives. In all derivatives the furoxan group remains the most reactive part of the molecule.

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Unsymmetrically substituted furoxans. VII. A ¹³C NMR study of a series of isomeric pairs of furoxans and the structure of the two isomeric chloro‐phenyl‐furoxans

Abstract: The structure of two isomeric chloro(phenyl)furoxans is proposed by comparison of their 13C nmr spectra with those of several unsymmetrically substituted furoxans and related furazans.

Cited by 29 publications

References 11 publications

Oxadiazoles

Oxadiazoles

The Furoxan System: Design of Selective Nitric Oxide (NO) Donor Inhibitors of COX-2 Endowed with Anti-Aggregatory and Vasodilating Activities

Structural and molecular-orbital study of the furoxan ring. Structures of 3-phenylfuroxan and 4-phenylfuroxan and comparison with related structures

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Unsymmetrically substituted furoxans. VII. A 13C NMR study of a series of isomeric pairs of furoxans and the structure of the two isomeric chloro‐phenyl‐furoxans

Abstract: The structure of two isomeric chloro(phenyl)furoxans is proposed by comparison of their 13C nmr spectra with those of several unsymmetrically substituted furoxans and related furazans.

Cited by 29 publications

References 11 publications

Oxadiazoles

Oxadiazoles

The Furoxan System: Design of Selective Nitric Oxide (NO) Donor Inhibitors of COX-2 Endowed with Anti-Aggregatory and Vasodilating Activities

Structural and molecular-orbital study of the furoxan ring. Structures of 3-phenylfuroxan and 4-phenylfuroxan and comparison with related structures

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Unsymmetrically substituted furoxans. VII. A ¹³C NMR study of a series of isomeric pairs of furoxans and the structure of the two isomeric chloro‐phenyl‐furoxans