The Isomerization of Aziridine Derivatives

Heine, Harold W.

doi:10.1002/anie.196205281

Cited by 60 publications

(24 citation statements)

References 20 publications

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“…wt. 450.2155): C , 69.31;H;6.71;N, 6.22. Found (450.2142 (mass spectrum)): C, 69.29; H, 6.53; Id, 6.13.…”

Section: Preparation Of Diastereomeric Cis-1-mentlzyl L-p-mentioning

confidence: 98%

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Studies Relating to Aziridine Antitumor Antibiotics. Part I. Asymmetric Syntheses. Part II. Chiral Aziridines and their Conversion to α-Aminoacids

Lown¹,

Itoh²,

Ono³

1973

Can. J. Chem.

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Separable diastereomeric cis-1-menthyl 2-phenyl-3-aziridinecarboxylates (4 and 5) were prepared by the Gabriel reaction. N-Acylation with p-nitrobenzoyl chloride or p-anisoyl chloride of 4 and 5 gives 7 and 8, and 23 and 24, respectively. Sodium iodide-catalyzed rearrangement of the N-acylated aziridines is rcgiospecific with exclusive attack at C-2 and from 8 is obtained the chiral 2-oxazolines cis-9 and trans-10 in a ratio of 30:70 together with the unsaturated amide 11. The structure of the latter was proven by independent synthesis. The intermediate I-menthyl N-p-nitrobenzoyl-3-iodophenyl-alaninate (18) was isolated at lower temperatures and shown to form the equilibrium mixture of 9 and 10 with triethylamine owing to partial racemization by a Finkelstein identity reaction. Use of an N-p-anisoyl substituent in the aziridine improves the yield of chiral 2-oxazolines by preventing the formation of 11, and allows the separation of pure cis-and trans-oxazolines for characterization. The aziridines bearing N-p-anisoyl substituents display a greater sensitivity to attack by weaker nucleophiles than thep-N-nitrobenzoyl analogs.Acid hydrolysis of 9 and 10 gives D-allo-a-phenylserine in an optical yield of about 17% from which 5 and 8 are tentatively assigned the 2R,3R configuration. Similar acid hydrolysis of the 2-p-anisyl-2-oxazoline (266) allowed the isolation of the interrnediatc I-menthyl 0-anisoyl-allo-p-phenylserinate (30a), hydrolysis of which gave D-allo-p-phenylserine in about 18% optical yield. The isolation of alloa-phenylserine only from cis-and trans-2-oxazolines is attributed to acid-catalyzed inversion at the benzylic center to the conformationally more stable allo form.

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“…wt. 450.2155): C , 69.31;H;6.71;N, 6.22. Found (450.2142 (mass spectrum)): C, 69.29; H, 6.53; Id, 6.13.…”

Section: Preparation Of Diastereomeric Cis-1-mentlzyl L-p-mentioning

confidence: 98%

“…When compound 8 was treated with a solution of sodium iodide (15) or potassium thiocyanate in refluxing acetone three products were obtained; the cis-and trans-2-oxazolines (9 and 10) and the unsaturated amide, 11 (see Scheme 3). Compounds 9 and 10 were produced in a ratio of 30:70.…”

mentioning

confidence: 99%

Studies Relating to Aziridine Antitumor Antibiotics. Part I. Asymmetric Syntheses. Part II. Chiral Aziridines and their Conversion to α-Aminoacids

Lown¹,

Itoh²,

Ono³

1973

Can. J. Chem.

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“…[16][17][18] It is obvious from the literature that E/Z isomerization barrier will be much higher for most imines. 19 The detailed investigations of the imine interconversion and the characterization of the new compound 1X are now underway. This was not, however, observed (the observed energy barrier was similar to conjugated imines).…”

Section: The Stereoselective Synthesis and The Nitrogen Interconversimentioning

confidence: 99%

“…Above 403 K, in nitrobenzene there is a competition between the imine interconversion and the aziridine rearrangement. 19 The detailed investigations of the imine interconversion and the characterization of the new compound 1X are now underway. Thus, we attribute the observed 1 H DNMR effect to nitrogen inversion of aziridine ring nitrogen.…”

Section: The Stereoselective Synthesis and The Nitrogen Interconversion Studies Of 2-(tert-butoxymethyl)-1-[n-(4-methylbenzenesulfonyl) (mentioning

confidence: 99%

The Stereoselective Synthesis and the Nitrogen Interconversion Studies of 2-(tert-butoxymethyl)-1-[NT-(4-methylbenzenesulfonyl) (4-methylphenoxy) imidoyl] aziridine

Dabbagh

Modarresi‐Alam

2000

Journal of Chemical Research

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Aziridines are very important precursors to a wide range of biologically active molecules such as amino acids, antibiotics, alkaloids, and many others. 1 The two most important aspects of this class of compounds have been the stereo-regio-selectivity of their synthesis and energy barrier of nitrogen inversion. 1-3 Both aspects have very important effects on their physical and/or chemical behaviours. Lwowski and co-workers reported a highly stereoselective synthesis of aziridines via a reaction of imidoyl nitrene with olefines. 4 Dabbagh and coworkers reported that certain imidoyl nitrenes are known to have moderate reactivity with higher selectivity. 5,6 Recently, Atkinson and co-workers have described the preparation of range of aziridines via reagent-controlled diastereoselective aziridination of alkenes using 3-acetoxyaminoquinazolinones. 7 They further reported the acid-catalysed aziridine ring-opening with retention of configuration. Furthermore, the interconversion of the isomers on nitrogen of nitrogen-containing organic compounds has been the cornerstone of research interests for the last half century. 2,8 Generally, the rapid nitrogen inversion of ordinary amines focused the attention on aziridine with its much lower inversion rate, because of strain in the three member ring. 2,9 The aziridines' nitrogen inversion has been investigated in detail. 2,3,9

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“…Our initial observations of a chloride-promoted isomerization suggested that the well-known rearrangement of certain N-acyl aziridines (7) should also be possible with the benzylaziridine system 1. If compound 1 could be isomerized to the corresponding oxazoline 6, one would have a useful protecting group for carboxylic acids which incorporates a chromophore for use as a chromatographic marker.…”

mentioning

confidence: 98%

A mild, general preparation of N-acyl aziridines and 2-substituted 4(S)-benzyloxazolines

Bates¹,

Varelas²

1980

Can. J. Chem.

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The Isomerization of Aziridine Derivatives

Cited by 60 publications

References 20 publications

Studies Relating to Aziridine Antitumor Antibiotics. Part I. Asymmetric Syntheses. Part II. Chiral Aziridines and their Conversion to α-Aminoacids

Studies Relating to Aziridine Antitumor Antibiotics. Part I. Asymmetric Syntheses. Part II. Chiral Aziridines and their Conversion to α-Aminoacids

The Stereoselective Synthesis and the Nitrogen Interconversion Studies of 2-(tert-butoxymethyl)-1-[NT-(4-methylbenzenesulfonyl) (4-methylphenoxy) imidoyl] aziridine

A mild, general preparation of N-acyl aziridines and 2-substituted 4(S)-benzyloxazolines

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