Synthesis of 20-hydroxyecdysone oxime, its diacetonide, and their 14,15-anhydro derivatives

Galyautdinov, I. V.; Ves'kina, N. A.; Афонькина, С. Р.; Халилов, Л. М.; Odinokov, V. N.

doi:10.1134/s1070428006090132

Cited by 14 publications

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“…Instead of rearrangement, boron trifluorideether complex in methylene chloride promoted deprotection of the hydroxy groups in positions 2 and 3 of DOI: 10.1134/S1070428009100066 The 1 H and 13 C NMR spectra of compound VIII were similar to those of previously described compound III [7] (with small differences related to the lack of acetonide protection at C 2 and C 3 in VIII). Treatment of oximes II and V with phosphoric anhydride, phosphorus pentachloride, thionyl chloride, or p-toluenesulfonyl chloride resulted in the formation of mixtures of products.…”

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confidence: 57%

“…In the 13 C NMR spectra of oximes V and VI, the α-methylene carbon atom (C 7 ) resonated in a stronger field (δ C 26.18 and 26.16 ppm, respectively) than the C 5 atom (CH, δ C 42.28 and 42.48 ppm), indicating their syn (C 7 ) and anti (C 5 ) orientation with respect to the N-OH group. This means that oximes V and VI have E configuration [7,10].…”

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confidence: 97%

“…By treatment of 20-hydroxyecdysone diacetonide I with hydroxylamine hydrochloride in pyridine we obtained a mixture of the corresponding (E)-and (Z)-oximes II and III (Scheme 1) [7]. The oximation of 7,8-dihydro-20-hydroxyecdysone diacetonide IV under analogous conditions gave (E)-oxime V (Scheme 2).…”

mentioning

confidence: 97%

“…Ecdysteroid oximes and their chemical properties have been studied poorly. We previously reported on the synthesis of 20-hydroxyecdisone oxime and the corresponding diacetonide [7].…”

mentioning

confidence: 99%

“…Ecdysteroid oximes and their chemical properties have been studied poorly. We previously reported on the synthesis of 20-hydroxyecdisone oxime and the corresponding diacetonide [7].In the present work we succeeded in effecting Beckmann rearrangement of (E)-oximes II and V derived from 20-hydroxyecdysone and its 7,8-dihydro analog with a view to transform the ecdysteroid B ring into seven-membered lactam ring, a fragment intrinsic to azabrassinosteroids [8].By treatment of 20-hydroxyecdysone diacetonide I with hydroxylamine hydrochloride in pyridine we obtained a mixture of the corresponding (E)-and (Z)-oximes II and III (Scheme 1) [7]. The oximation of 7,8-dihydro-20-hydroxyecdysone diacetonide IV under analogous conditions gave (E)-oxime V (Scheme 2).…”

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20-hydroxyecdysone oximes and their rearrangement into lactams

et al. 2009

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E)-Oximes derived from 20-hydroxyecdysone diacetonides and 7,8-dihydro analog were converted into the corresponding lactams (6-oxo-5a-aza-5a-homo derivatives) via Beckmann rearrangement. 14,15-Anhydro-20-hydroxyecdysone (Z)-oxime under analogous conditions (reaction with p-toluenesulfonyl chloride in acetone in the presence of Na 2 CO 3 ) gave rise to 20-hydroxyecdisone 20,22-acetonide (Z)-O-tosyloxime which did not undergo Beckmann rearrangement.Oximes are widely used in organic synthesis, and they exhibit diverse biological activity [1]. In the recent years, interest in oximes of the steroid series considerably increased [2,3]. This interest was stimulated primarily by the isolation of steroidal oximes from the marine sponges Cynachyrella alloclada and S. apion [4]. which, like their synthetic analogs [5], turned out to effectively inhibit aromatase (the key enzyme in the biosynthesis of estrogens) and attracted attention as potential antitumor agents [6]. Ecdysteroid oximes and their chemical properties have been studied poorly. We previously reported on the synthesis of 20-hydroxyecdisone oxime and the corresponding diacetonide [7].In the present work we succeeded in effecting Beckmann rearrangement of (E)-oximes II and V derived from 20-hydroxyecdysone and its 7,8-dihydro analog with a view to transform the ecdysteroid B ring into seven-membered lactam ring, a fragment intrinsic to azabrassinosteroids [8].By treatment of 20-hydroxyecdysone diacetonide I with hydroxylamine hydrochloride in pyridine we obtained a mixture of the corresponding (E)-and (Z)-oximes II and III (Scheme 1) [7]. The oximation of 7,8-dihydro-20-hydroxyecdysone diacetonide IV under analogous conditions gave (E)-oxime V (Scheme 2). When the oximation product of 7,8-dihydro analog IV was treated with a solution of potassium hydroxide in ethanol, we obtained 14,15-anhydro-7,8-dihydro-20-hydroxyecdysone diacetonide (E)-oxime VI. An attempt to reduce the latter into 7,8-dihydro-14-deoxy-20-hydroxyecdysone diacetonide oxime by catalytic hydrogenation over Raney nickel resulted in the formation of 7,8-dihydrostachysterone B diacetonide VII (Scheme 3). The 13 C NMR spectrum of VII was fairly similar to the spectrum of 7, 8-dihydrostachysterone B 20,22-acetonide [9], and some differences were related to the presence of an additional O,O′-isopropylidene protective group at positions 2 and 3 of compound VII.The structure of oximes V and VI was confirmed by the 1 H and 13 C NMR spectra. The signals were assigned using one-( 1 H, 13 C, APT) and two-dimensional correlation techniques (COSY, HSQC, HMBC). In the 13 C NMR spectra of oximes V and VI, the α-methylene carbon atom (C 7 ) resonated in a stronger field (δ C 26.18 and 26.16 ppm, respectively) than the C 5 atom (CH, δ C 42.28 and 42.48 ppm), indicating their syn (C 7 ) and anti (C 5 ) orientation with respect to the N-OH group. This means that oximes V and VI have E configuration [7, 10].Oximes of the ecdysteroid series did not undergo Beckmann rearrangement under conditions of acid catalysis. ...

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supporting

confidence: 57%

mentioning

confidence: 97%

mentioning

confidence: 97%

“…Ecdysteroid oximes and their chemical properties have been studied poorly. We previously reported on the synthesis of 20-hydroxyecdisone oxime and the corresponding diacetonide [7].…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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20-hydroxyecdysone oximes and their rearrangement into lactams

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