The Chemistry of Lactim Ethers

Глушков, Р. Г.; Граник, В. Г.

doi:10.1016/s0065-2725(08)60974-5

Cited by 34 publications

(16 citation statements)

References 58 publications

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“…27 Imidates are mostly employed for the preparation of cyclic imines. [175] The reaction of N-(ethoxymethylene)aniline with 2 equivalents of phenylmagnesium bromide gives rise to N-benzylideneaniline in almost quantitative yield. The sole formation of this imine can be explained by the stability of the initial adduct of the imidate with the Grignard reagent.…”

Section: Nhr 3 Homentioning

confidence: 99%

Product Class 7: Imines

Padwa¹,

Bellus²

2005

Category 4. Compounds With Two Carbon Heteroatom Bonds

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Compounds with the general structure R 1 R 2 C=NR 3 , referred to as imines, were first obtained by Schiff via condensation of ketones and aldehydes with primary amines. Therefore, the condensation products are also called Schiff bases. In addition, the nominations azomethine, ketimine (derived from ketones), aldimine (derived from aldehydes), and anil (derived from anilines) are in use. It is recommended that the terms imine(s), ketimine(s), or aldimine(s) are used, rather than Schiff base(s) or azomethine(s).Since imines have to be considered as analogues of carbonyl compounds, many of the chemical properties are similar to the latter. Imines are used in new C-C bond formations, and reactions with electrophiles (e.g., aldehydes, alkyl halides), and the C=N moiety can undergo nucleophilic reactions. Generally, imines are very useful compounds in organic synthesis, as they are used in several syntheses of aza-heterocyclic compounds. Most imines are stable in an alkaline medium and therefore can be dried over potassium hydroxide. In diluted acid, however, they are easily hydrolyzed. In many cases intermediary imines cannot be isolated because of their lability. The presence of a C=N bond creates the possibility for E/Z isomerism (syn/anti). It has been recognized that such geomet-

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Section: Nhr 3 Homentioning

confidence: 99%

Product Class 7: Imines

Padwa¹,

Bellus²

2005

Category 4. Compounds With Two Carbon Heteroatom Bonds

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“…We are grateful to Prof. Y. Znubushi and to Prof. B. Witkop for kindly providing samples of the dl-lactam 7 and of natural pumiliotoxin-C. We thank the Fonds National Suisse de la Recherche Scientifique, Sandoz Ltd, Basel and Givaudan SA, Vernier for financial support of this work. lo) For a review article on lactim-ethers see [25].…”

Section: Transformation Of the Indanols 15 To Dl-pumiliotoxin-c (4) (mentioning

confidence: 99%

ChemInform Abstract: A NEW TOTAL SYNTHESIS OF DL‐PUMILIOTOXIN C VIA AN INDANONE

Oppolzer¹,

Fehr²,

Warneke³

1977

Chemischer Informationsdienst

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~~~~Summary dl-Pumiliotoxin-C (4) was synthesized in a practical manner from trans-4-hexenal (9). The key step 14+15 (Scheme 3) involves an intramolecular Dielv-Alder reaction giving mainly the ciy-fused indanols 15a, which were converted to the cis-fused kctone 16. After Beckmann-rearrangement of 16 the octahydroquinolinone 7 was transfoimed to the lactim-ether 23. (Scheme 7). Reaction of 23 with propylmagnesium bromide followed by hydrogenation furnished dl-4 in a highly stereoselective fashion. . The complex stereochemical features 2, and the paucity of this physiologically active alkaloid provide a considerable challenge to the synthetic chemist [3-61. We have recently met this challenge by using the intramolecular Diels-Alder reaction 2 + 3 as the crucial step in the synthesis outlined below3) (Scheme 1 ) ; one of its key features is that during the conversion of 1 to 4 the original chiral center of the amine 1 controls to a major extent the configuration of the other chiral centers which are formed simultaneously in the cycloaddition process.We now wish to report an alternative synthetic scheme (5 i 6 i 7 --f 4) following a different stereochemical strategy in which center C(2) is induced by the other three chiral centers*) during the transformation 7 i 4; for their assembly an intramolecular cycloaddition 5 + 6 was envisaged. Since both trans-dienes 5a, as well as the corresponding cis-dienes (5b) may be considered as leading selectively to the required cis-junction of 6 the two isomeric trienols 11 and 12 were separately prepared from the dienynol 10 in a stereocontrolled manner.

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“…The solvent was removed by distillation followed by distillation of the imino ether. 0-Methyl-N-tertbutylformimidate (1): 70% yield; bp 90-100°; ir (CH2C12) 2960, 1670, 1370, 1190, 1170, 690 cm"1; nmr (CC14) 1.15 (s, 9 ), 3.50 (s, 3 H), 7.33 (s, 1 H); mass spectrum (70 eV) m/e 115.0997 (caled for CgHisNO, 115.0997), m/e (rel intensity) 115 (M+, 84), 101 (5), 100 (10), 86 (4), 4 (3), 72 (10), 68 (15), 60 (12), 57 (30), 56 (11), 43 (4), 42 (15), 41 (40), 39 (10), 30 (4), 29 (18), 28 (12), 27 (8), 18 (9). 15 (9).…”

Section: /Och Yxmentioning

confidence: 99%