Reactions of 4-aroyl-4-oxazolines and 3-aroyI-4,5-dihydrofurans

Lown, J. W.; Smalley, R. K.; Dallas, G.; Maloney, T. W.

doi:10.1139/v70-015

Cited by 7 publications

(5 citation statements)

References 1 publication

(2 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 2-(2'-thienyl)aziridine, 1, reacted readily stantially reduced resonance energy compared with diphenylcyclopropenone to give a 1:l with an aryl group. adduct assigned the 2-(2'-thieny1)-4-oxazoline structure 14 on the basis of its dipolarophilic (c) Aryl Isothiocyanates as Dipolarophiles activity (8,9). For example, treatment of 14 with…”

Section: (A) Acetylenic Dipolarophilesmentioning

confidence: 99%

“…We have reported that 3-aroyl-2-arylaziridines react with aryl isothiocyanates to form (a) N-phenylmaleimide afforded the known dihydrofuran adduct 15 (9) in 82 % yield with the expulsion of the 2-thiophen aldimine. The latter reaction shows that 4-oxazolines cleave thermally to 1,3-dipoles of the externally stabilized ketocarbene type even with a Zsubstituent of sub-4-aroyl-5-arylamino-4-thiazolines, 16, by 1,3-dipolar cycloaddition to the C==S bond followed by tautomerization and/or (b) 2-arylimino-4-aroyl-4-thiazolines 17 (10) (Scheme 1).…”

Section: (A) Acetylenic Dipolarophilesmentioning

confidence: 99%

See 1 more Smart Citation

1,3-Dipolar cycloaddition reactions of 2-(2′-thienyl)aziridines

Lown¹,

Matsumoto²

1970

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

The 1,3-dipolar cycloaddition of 2-(2'-thieny1)aziridines to a series of acetylenic and heterornultiple dipolarophiles leading to a series of new linked heterocycles is described. The versatility of these reactions suggests a general synthetic route to linked heterocycles.Canadian Journal of Chemistry, 48, 3399 (1970) We have recently described the preparation of the hitherto unknown 2-(2'-thieny1)aziridines (1) and have shown that, despite the lower resonance energy of the thiophene ring (20 kcal mole-' (2)) compared with benzene, 2-(2'-thieny1)-3-aroylaziridines undergo thermal cleavage of the 2-3 bond of the aziridine ring to azomethine u ylides at moderate temperatures. The transient dipoles could be trapped with olefinic dipolarophiles affording 2-(2'-thieny1)pyrrolidines.We report the examination of 1,3-dipolar cycloadditions of 2-(2'-thieny1)aziridines to acetylenic and heteromultiple bonds as a first approach to a general synthesis of linked heterocycles. (a) Acetylenic DipolarophilesBoth cis-and trans-3-benzoyl-l-cyclohexyl-2-(2'-thieny1)aziridine (1) reacted with dimethyl ~6~1 1 3 yl-3-deutero-2-(2'-thieny1)aziridine (91 % deuterium incorporation) gave 5 in which both branches of the 12 Hz AB quartet due to the methine protons were diminished to an equal extent (20 %). This discounts the trans-3-pyrroline structure 4 for the compound (which is in any case unlikely in view of the magnitude of the methine coupling) which would be expected to show one branch of the AB quartet diminished I C6Hll

show abstract

Section: (A) Acetylenic Dipolarophilesmentioning

confidence: 99%

Section: (A) Acetylenic Dipolarophilesmentioning

confidence: 99%

1,3-Dipolar cycloaddition reactions of 2-(2′-thienyl)aziridines

Lown¹,

Matsumoto²

1970

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Formation of products of types 16 and 17 are envisaged as involving cleavage (y) of the intermediate oxadiazolidines 10 and 11 to the nitrones 13 and 14 respectively (a reaction for which precedents and strong analogies exist (1, 2)) and cyclodehydration of the latter to 16 and 17 respectively. Although Schiff bases have occasionally been isolated from 1,3-dipolar cycloaddition reactions of 4-oxazolines, they are more often hydrolyzed to aldehyde and cyclohexylamine during the reaction (12) and so cyclohexylamine would be available for condensation to form 16 An alternative rationale for the formation of benzo [ f Iquinoxalines rather than benzo [ f ]-quinoxaline-1-oxides in these reactions suggested by a referee involves the reversible cycloaddition of Schiff bases to the N-oxide 1,3-dipoles (see Scheme 2).…”

Section: -P-nitrophenylnaphtho[l2-dlimidazolementioning

confidence: 99%

Reaction of 1-Nitroso-2-naphthylamine with 3-Aroylaziridines

Lown¹,

Akhtar²

1971

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

Reaction of 1-nitroso-2-naphthylamine with a series of 3-aroylaziridines affords (a) 3-arylbenzolflquinoxalines, (b) cyclohexylimino derivatives of 2-aroylnaphtho[1,2-d]imidazoles, and (c) a 2-arylnaphtho[l,2-dlimidazole. Electron-withdrawing substituents in either the 2 or 3 aryl moieties of the aziridine lead to preferential formation of products of type a whereas electron-donating substituents in either of these positions result in the formation of products of type b. The results of deuterium labelling and unambiguous synthet~c studies in support of the proposed 1,3-dipolar cycloaddition mechanism are discussed.La reaction de la nitroso-1 naphtylamine-2 avec une serie de benzoyl-3 arizidines conduit A (a) des phenyl-3 benzolflquinoxalines, (b) des derives cycloh6xylimino des benzoyl-2 naphto[l,2-dlimidazoles, et (c) une phenyl-2 naphta[l,2-dlimidazole. Si le noyau aromatique de I'aziridine porte des substituants electro-affinitaires en positions 2 ou 3, les produits formis d'une facon prefkrentielle sont ceux du type a ; par ailleurs si des substituants sont blectro-rkpulsifs les produits formts d'une facon prCf6rentielle sont ceux du type b. On discute de nos rksultats-molkules marquees par du deterium et synthkses nonambiguesen fonction d'un mkanisme de cycloaddition dipolaire-1,3.

show abstract

“…Irradiation of a benzene solution of 42 for 2.5 h gave a 65% yield of a bright yellow solid, mp 147-148 °C and exhibiting the spectral characteristics of 46, as reported by the earlier workers. 18 The mass spectrum of this product, however, was quite revealing in that it showed a peak at m/e 105, characteristic of 2/i-pyran-2-ones, having a phenyl substituent at the C6 position.19™21 On the basis of the mass spectral data and other spectral evidences, we reasoned that the 2H-pyran-2-one obtained from 42 is correctly represented as 3,5,6-triphenyl-2/i-pyran-2-one (50) and not 46, as suggested by earlier workers. Further confirmation of the structure of 50 was, however, derived by its comparison with an authentic sample of 3,5,6-triphenyl-2H-pyran-2-one (50), prepared by a reported procedure.…”

mentioning

confidence: 99%