R. V. Shafikov

7,8-dihydro analogs of ecdysteroids

Reactions of 20-hydroxyecdysone, its diacetonide, and 24,25(25,26)-anhydro derivative with lithium tetrahydridoaluminate gave the corresponding 6α- and 6β-epimeric alcohols and 7,8-dihydro analogs.

Stereochemistry of Hydride Reduction of 20-Hydroxyecdysone Derivatives

The 6-oxo group in 2,3:20,22-di-O-isopropylidene derivatives of 20-hydroxyecdysone and its 24,25/25,26-anhydro analog is reduced with NaBH4-CeCl3 in a stereoselective fashion to afford the corresponding 6α-alcohols. In the first case, the reaction is accompanied by dehydration to give Δ14-bond. Reduction of the same substrates with NaBH4 or LiAlH4 in the absence of CeCl3 leads to mixtures of 6α- and 6β-hydroxy derivatives, the latter prevailing. In all cases, epimerization at C5 occurs.

Regio and stereo directional oxidation of ecdysteroids and their 7,8-dihydroanalogs with ozone in pyridine

The oxidation of ecdysteroids and their 7,8-dihydroanalogs with ozone in pyridine occurred regio- and stereoselectively at the hydroxy groups of the A ring giving 2-dehydro-3α-hydroxy derivatives.

20-hydroxyecdysone oximes and their rearrangement into lactams

Abstract(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 Na2CO3) gave rise to 20-hydroxyecdisone 20,22-acetonide (Z)-O-tosyloxime which did not undergo Beckmann rearrangement.

Chemoenzymatic synthesis of (2R,6R,10R)-6,10,14-trimethylpentadecan-2-ol, sex pheromone of rice moth (Corcyra cephalonica), and of its (2S,6R,10R)-diastereomer

Based on the catalyzed by lipase Amano PS kinetic separation of the two-component mixture of diastereomers of (2RS,6R,10R)-6,10,14-trimethylpentadecan-2-ol in the acylation with the succinic anhydride we obtained the (2R,6R,10R)-6,10,14-trimethylpentadecan-2-ol, the sex pheromone of rice moth (Corcyra cephalonica) and its (2S,6R,10R)-diastereomer.

Analogs of ecdysteroids with a tetrasubstituted Δ8,14-bond

By hydrogenation of (20R,22R)-6α,14α,25-trihydroxy-and (20R,22R)-6β,14α,25-trihydroxy-2,3:20,22-bis(isopropylidenedioxy)-5α-cholest-7-enes on a catalyst (Raney nickel) the corresponding (5α,6α)-and (5β,6β)-epimers of previously unknown Δ8,14-6-hydroxy derivatives of ecdysteroids were synthesized.

New possibilities in a synthesis of (2R,4'R,8'R)-α-tocopherol (natural vitamin E)

New methods for the synthesis of homochiral C14 and C15-terpenoids desired as building blocks for phytilic side chain of natural α-tocopherol have been developed. A natural phytone resulted from the proposed effective method of chlorophyll ozonolysis was used in a synthesis of optically active terpenoids. Chiral chroman compound for vitamin E, namely, (S)-(-)-6benzyloxy-3,4-dihydro-2,5,7,8-tetramethylchroman-2-methanol was obtained by enantioselective transesterification of the corresponding racemic alcohol catalysed by Amano PS lipase from Burkholderia cepacia in ionic liquid [bmim]PF6.