S. N. Sokolov

Synthesis of Ecdysteroids and Related Compounds

Literature data published in 1998-2002 on the chemical synthesis of ecdysteroids and their structural analogs were reviewed.

STRUCTURE—ACTIVITY RELATIONSHIP OF INSECTICIDAL STEROIDS. IV. 3β-CHLOROSUBSTITUTED DERIVATIVES OF CHOLESTEROL AND β-SITOSTEROL

The toxicity of 3β-chlorosteroids 1-8 for colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by a contact-intestinal method. The most active insect growth and development regulators of the studied compounds are 3β-chlorocholest-5-ene (1a), 3β-chloro-5α,6β-diol 6-formate (3b), 3β-chloro-7α-hydroxy-6-ketone (4a), and 3β-chloro-5α-bromo-Δ4-6-ketone (8).

Synthesis of α-chloropyridine-containing oximes of 3β,5-dihydroxy-6-ketosteroids

New derivatives of steroidal 6-ketoximes containing α-chloropyridine neonicotinoid groups characteristic of bioactive compounds were synthesized by formation of oximes of cholestane and stigmastane 3β,5-dihydroxy-6-ketosteroids with O-(2-chloropyridin-5-ylmethyl)hydroxylamine in the presence of zinc or tin(IV) chloride.

Structural Dependence of Insecticidal Activity of 5α-Hydroxy-Δ7-6-ketosteroids

The toxicity of 5α-hydroxy-Δ7-6-ketosteroids for colorado beetleLeptinotarsa decemlineataSay. larvae was studied by topical and GI administration.

Synthesis of (Z)- and (E)-3-(2-chloropyridin-5-ylmethyl) oximino-(22E,24R)-ergosta-4,7,22-trienes and their oxidative transformations

(Z)- and (E)-3-(2-chloropyridin-5-ylmethyl)oximino-(22E,24R)-ergosta-4,7,22-trienes (5–6) were synthesized by chemical transformation of ergosterol. Several oxidative transformations of them were studied. It was found that oxidation of these compounds by chromium(VI) oxide formed the corresponding O-substituted 3-ketoximes of the mycosteroid (22E,24R)-ergosta-4,7,22-trien-3,6-dione (7) and (8), which contained α-chloropyridine fragments characteristic of biologically active neonicotinoids. It was shown that oxidation of 5 and 6 by selenium dioxide occurred with formation of the corresponding 9α-hydroxy derivatives 9 and 10.

Structure-Activity Relationship of Insecticidal Steroids. III. Δ4,7-6-Ketosteroids

The toxicity of steroids 1-11 for colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by contact-intestinal treatment. Active insect-growth regulators were found among the studied compounds.

Novel Synthesis of 5-Hydroxy-5α-cholesta-2,7-dien-6-one and Its Criegee Hydroxylation

Cholesterol (1) is used to synthesize again 5α-hydroxy-2,7-dien-6-one (5) through the intermediates 2-4. cis-Hydroxylation of 5 with OsO4and subsequent acetylation give steroids 6-8. Dehydration of 5α-hydroxy-6-ketone 6 forms the unsaturated compounds 9-11

Synthesis of the O-(2-chloropyridin-5-ylmethyl)oxime of 20-hydroxyecdysone

The new ecdysteroid derivative 20-hydroxyecdysone O-(2-chloropyridin-5-ylmethyl)oxime (3) was synthesized via the reaction of 20-hydroxyecdysone (1) and O-(2-chloropyridin-5-ylmethyl)hydroxylamine (2) in Py in the presence of SnCl4.

Synthesis of α-chloropyridine derivatives of γ-aminobutyric acid

The sodium salt of N-(6-chloronicotinoyl)-γ-aminobutyric acid, a structural analog of the known nootropic and vasidilating drug picamilon, was synthesized via Schotten–Baumann acylation of γ-aminobutyric acid with 6-chloronicotinoyl chloride and subsequent neutralization of the N-(6-chloronicotinoyl)-γ-aminobutyric acid that was obtained in >60% yield.

Synthesis of new α-chloropyridine derivatives of steroidal 3β,5α,6β-triols and 3β,5-dihydroxy-6-ketones

New steroid derivatives containing 6-chloropyridine groups characteristic of the alkaloid epibatidine and neonicotinoid insecticides were synthesized by reacting 3β,5α,6β-trihydroxysteroids or 3β,5-dihydroxy-6ketosteroids with 2-chloro-5-chloromethylpyridine.