- An easy method for the generation of amides from ketones by a Beckmann type rearrangement mediated by microwave
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A facile and efficient procedure is developed for one-pot synthesis of amides from ketones in the presence of P2O5/SiO 2 reagent in dry media under microwave irradiation. Ketoximes indirectly in the same conditions gave amides by Beckmann rearrangement.
- Eshghi, Hossein,Gordi, Zinat
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p. 2971 - 2978
(2007/10/03)
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- Schmidt reaction on camphor. Part I. Structure of the products
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A reinvestigation of the major product from the Schmidt reaction on camphor has led to the assignment of the structure as 1,9,9-trimethyl-3-oxo-2,8-diazabicyclononane (5).The structure has been established by high-field proton and carbon-13 nuclear magnetic resonance, as well as degradation to the imine ester 4.Confirmation of the structure of 5 was achieved by X-ray crystallography.Compound 5, C10H18N2O, crystallized in space group P21/a with a = 14.934(1) Angstroem, b = 10.973(1) Angstroem, c = 12.341(1) Angstroem, β = 92.0 deg, and Z = 8.The relatively rare cis amide linkage is present in the molecule.In addition to the amino amide 5, the Schmidt reaction on camphor leads to small amounts of the tetrazole 8 and the imine nitrile 9.
- Hunter, Norman R.,Khan, M. Zafar,Marat, Kirk,El-Kabbani, Ossama A. L.,Delbaere, Louis T. J.
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p. 137 - 149
(2007/10/02)
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- Camphor/Longicamphor and 7β-Formylnorlongifolane/7β-Acetylnorlongifolane Oximes: A Comparative Beckmann Rearrangement Study
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Camphor oxime (3)/longicamphor oxime (4) have been shown to undergo Beckmann fragmentation on exposure to tosyl chloride in pyridine generating olefinic nitriles: 3->5+6 and 4->7+8+9; in the case of 4 this reaction provides an entry into the bicyclononane system characteristic of the secolongifolene diol fungal metabolite (10). 7β-Formylnorlongifolane oxime (14)/7β-acetylnorlongifolane oxime (15) when treated with the same Beckmann catalyst under similar conditions, afford the nitrile (16)/amide (17); on hydrolysis with base 17 gives the amine 18.Reaction of longicamphor (2) with hydroxylamine-O-sulfonic acid, however, a ffords the nitrogen-insertion product, α-longicamphidone (24) besides the fragmented nitrile (7).
- Satyanarayana, N.,Shitole, H. R.,Nayak, U. R.
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p. 997 - 1001
(2007/10/02)
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- Unusual regiochemistry in a beckmann-like rearrangement of camphor. α-Camphidone via methylene migration.
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Reaction of camphor with hydroxylamine-O-sulfonic acid affords the nitrogen insertion product α-camphidone by migration of the methylene group rather than the bridgehead. Since Beckmann rearrangements of trigonal oximes afford bridgehead cleavage products with camphor, an alternative synchronous rearrangement of a tetrahedral intermediate is proposed for this Beckmann-like reaction.
- Krow, Grant R.,Szczepanski, Steven
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p. 4593 - 4596
(2007/10/02)
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