Carbodiimide-sulfoxide reactions. VIII. Reactions of oximes and hydroxylamines

Abstract

2,4-Dinitrophenylhydrazone.-Compound VI, 34 mg, was refluxed 5 min with 30 mg of 2,4-dinitrophenylhydrazine in 4 ml of methanol containing 0.1 ml of 6 N HC1. After cooling to room temperature the reaction mixture was centrifuged. The precipitate was crystallized from methanol, yield 27 mg, mp 138-1410.

New Synthesis of 18-Norestradiol

“…Apart from the expected 10 and 11, the formation of several different secondary alcohols was noticed, as by-products of suspected borane rearrangements [20]. We noticed that this process did not occur when powdered LiBH 4 was added 8 ). Best results were achieved when a solution of 9 in abs.…”

“…Therefore, estrone (2) ± after protection as 3-methyl ether ± was transformed [7] (Scheme 1) into the corresponding oxime in nearly quantitative yield. According to a procedure published by Moffat and coworkers [8], subsequent treatment with dicyclohexylcarbodiimide (DCC) and CF 3 COOH in a solution of DMSO and benzene led to seco-nitrile 3. However, upscaling using the above procedure failed.…”

“…However, upscaling using the above procedure failed. Due to a remarkable pH dependency of this cleavage reaction [8], we found, that CF 3 COOH had to be added in aliquots to a cooled solution of the oxime in DMSO and CCl 4 giving ± after column chromatography ± a 66% yield of 3 at best.…”

A convenient method for the synthesis of nitrones by oxidation of N,N-disubstituted hydroxylamines with N-tert-butylphenylsulfinimidoyl chloride

“…Several effective metal catalysts [7][8][9][10] and oxidizing agents [11][12][13] were then developed for this direct oxidation reaction. Another method for the preparation of nitrones is the oxidation of N,N-disubstituted hydroxylamines 6,[14][15][16] in which yellow mercuric oxide 17 is most commonly used as an oxidant. Although this method is useful particularly for the preparation of labile nitrones due to its mild reaction conditions, it is yet desired to develop a new and more efficient oxidant other than the toxic mercuric compound in order to establish a useful method for the preparation of nitrones by oxidation of N,Ndisubstituted hydroxylamines.…”

Biosynthetic Pathway for the Cyanide-Free Production of Phenylacetonitrile in Escherichia coli by Utilizing Plant Cytochrome P450 79A2 and Bacterial Aldoxime Dehydratase

“…Chemical manufacturers currently synthesize PAN using CN Ϫ , which was shown to be highly toxic to animals (2, 3) and may cause serious environmental pollution. Although alternative synthetic pathways for the CN Ϫ -free production of nitriles have been reported (4)(5)(6)(7)(8), they also require strong chemicals and/or high energetic loads. The production of PAN via biocatalysis in the absence of toxic chemicals has the potential to reduce environmental burden.…”