Convenient synthetic routes to α-oligosiloxanylacrylonitriles

Novel 1,4-elimination reaction of C,N-bis(trimethylsilyl)-C- trimethylsiloxymethylketenimine and retro Diels-Alder reaction of 2-oligosiloxanyl-5-norbornene-2-carbonitrile cleanly gave α-oligosiloxanylacrylonitriles in excellent yield.     

Stereoselective routes to 3-hydroxy and 3,4-dihydroxy derivatives of 2-aminocyclohexanecarboxylic acid

The Diels-Alder adduct of ethyl (E)-3-nitroacrylate and furan provides a versatile template for the stereoselective synthesis of mono and dihydroxylated derivatives of 2-aminocyclohexanecarboxylic acid (ACHC). The hydroxylated ACHC derivatives can be considered to be useful building blocks for β-peptides.     

Anodic oxidation studies of oxygenated biphenyls. Convenient synthetic routes to certain functionalized biphenyls

The anodic oxidation of oxygenated biphenyls produces phenyl-substituted $\text{p}$-quinol ether ketals in good-to-excellent yield. These compounds are useful substrates for preparation of more highly functionazized biphenyls.     

Synthetic routes to 1,5-dihydro-5-oxo-4,1-benzoxazepines and to 5-oxooxazolo[3,2-a]quinolines

The literature concerning phenacyl anthranilate, N- phenacylanthranilic acid and phenacyl N-phenacylanthranilate is clarified. Phenacyl anthranilate is dehydrated to 1,5-dihydro-5-oxo-2-pheny 1-4,1-benzoxazepine by treatment with phosphoryl chloride; other examples of this reaction are described. A preparation of 4-methyl-5-oxo-2-phenyloxazolo[3,2-a]quinoline from N-phenacylanthranilic acid and propionic anhydride is reported.     

Synthesis of Cholest-5-en-24-oxo-3b, 19-Diacetate

Two biologically active 19-hydroxylated sterols, 24-methylenecholesta-3b, 5a, 6b, 19- tetrol 1, 24-methylenecholesta-5-ene-3b, 7b, 19-triol 2, were isolated from the soft corals, Nephthea albida and Nepthea tiexieral verseveldt by L. M. Zeng1,2. 1 showed strong anti-inflamatory activity comparable with dexamethone and 2 showed potent anti-leukemic activity (IC50 0.01 mg/mL). We have designed a synthetic route for the synthesis of 1 and 2 as shown in Scheme 1. In this route, cholest-5-en-…     

A Convenient Synthesis of Diversely Substituted N,N-Dimethyl-4-oxo-2-(E)-alkenamides

An efficient synthesis of diversely substituted N,N-dimethyl-4-oxo-2-(E)-alkenamides is reported. These derivatives were obtained in three steps from I,4benzodioxin with fair to good yields     

Transformation of 3-oxo-17-ethylenedioxy-19-mesyloxy-delta-1,4-androstadiene in 3 instances to A-homo-19-norsteroids

4-oximino-17-ethylenedioxy-A-homo-δ^1(10),2,4a-19-nor-androstatriene is formed by treatment of 3-oximino-17-ethylenedioxy-19-mesyloxy-δ^1,4-androstadiene with sodium hydroxide. An analogous reaction occurs with the corresponding semicarbazone, but under the same conditions 3-hydrazino-17-ethylenedioxy-19-mesyloxy-δ^1,4-androstadiene leads to 17-ethylenedioxy-A-homo-δ^2,4,5(10)-19-norandrostatriene.     

Syntheses and stereochemistry of 4-hydroxy tetrahydroisoquinolines in the 1-benzyl and 1-phenethyl series. Efficient routes to isopavines and homoisopavines

The title compounds have been prepared in high yield $\text{via}$ cyclisation of urethane acetals.     

Convenient preparative method and crystal structures of (tripenylphosphine)gold(I) enolate and homoenolate complexes

Trimethylsilyl ethers of enol and cyclopropanol react with (triphenylphosphine)gold(I) chloride in the presence of cesium fluoride to give regioselectively carbon-bound (triphenylphosphine)gold(I) enolate and (triphenylphosphine)gold(I) homoenolate complexes. The first C-ray crystallography of these gold(I) complexes elucidated linear CAuP structures.     

Convenient Route to Thiocarbonates from Alcohols,Thiols, and Triphosgene

An efficient and simple one-pot, three-component procedure has been introduced for the preparation of various thiocarbonates from thiols, alcohols, and triphosgene in dichloromethane.     

Steroids and sex hormones. Synthesis of 5- and 5- -17-oxo-19-hydroxy-3-aza-3, 19-cyclo-A-homo-androstane

The synthesis of the novel title compounds ( 2 and 3 ) is described. These two isomers differ from structure 1 , ascribed to the salamander alkaloid cycloneosamandione, with respect to ring A/B fusion and to the ketone position.     

Preparation of the enantiomers of 19-epoxy docosahexaenoic acids and their 4-hydroxy derivatives

By the action of NBS in aq. DME, dl-19-bromo-20-hydroxy-DHA methyl ester 5 was prepared, which was effectively resolved by lipase PS and vinyl acetate in the presence of a thiacrown ether to give 7 and 8, each being transformed into the corresponding epoxides, 1 and 2, respectively. The absolute configuration of 8 was established by the Kusumi–Moscher method. For the purpose of biological evaluation, both epoxides were converted to the γ-lactones 3 and their 4-hydroxy derivatives 4.     

Steroids,LIII: New routes to aminosteroids

Summary Steroid ketoximes were reduced with sodium tetrahydroborate in the presence of nickel chloride or molybdenum trioxide. These processes yielded 17- and 20-aminosteroids (1c–5c) in higher yields than common reduction methods.

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Steroide, 53. Mitt.: Neue Wege zu Aminosteroiden

Zusammenfassung Oxime von Ketosteroiden wurden mit NaBH₄ in Gegenwart von NiCl₂ und MoO₃ reduziert. Dieses Verfahren lieferte 17- und 20-Aminosteroide(1c–5c) in größeren Ausbeuten als übliche Methoden.

     

Synthetic routes to cyclopropylidenecarbinols and to cyclopropylidienes

Functionalized alkylidine cyclopropanes have beeen prepared from 1-seleno 1-vinyl cyclopropanes using [2,3] sigmatropic rearrangement of their corresponding selenonium ylides. A comparison with sulphur analogues is presented.