Lactams oximes

Hydrolysis Oxidation Photolysis Esters, lactones, amides, lactams, oximes, imides, and malonic ureas Amines, sulfides, disulfides, sulfoxides, phenol anions, thiols, nitriles, and catechols Aromatic hydrocarbons, aromatic heterocyclics, aldehydes, and ketones... 

The reaction of lactim ethers with hydroxylamine results in lactam oximes.9,72,73, 78 This reaction became important when the lactam oximes were found to undergo the Beckmann rearrangement with polyphosphoric acid, yielding polymethyleneureas79 (Scheme 11). 

U-Alkylation. Dimethyl sulfate is a powerful alkylating agent and has been used for the methylation of almost every imaginable nucleophile over the years. The variety of oxygen nucleophiles include carboxylic acids, alcohols, phenols, lactams, oximes, pyridine A-oxides, hydroxylamines, hydroxamic acids, and hydroperoxides. ... 

Ingredients. Nylon-6 is produced commercially from caprolactam [105-60-2] which is the most important lactam industrially. AH industrial production processes for caprolactam are multistep and produce ammonium sulfate [7783-20-2] or other by-products. Approximately 95% of the world s caprolactam is produced from cyclohexanone oxime [100-64-1] via the Beckmann rearrangement (144). The starting material for cyclohexanone can be... 

Nylon-12. Laurolactam [947-04-6] is the usual commercial monomer for nylon-12 [24937-16-4] manufacture. Its production begins with the mixture of cyclododecanol and cyclododecanone which is formed in the production of dodecanedioic acid starting from butadiene. The mixture is then converted quantitatively to cyclododecanone via dehydrogenation of the alcohol at 230—245°C and atmospheric pressure. The conversion to the lactam by the rearrangement of the oxime is similar to that for caprolactam manufacture. There are several other, less widely used commercial routes to laurolactam (171). 

The reaction with oximes of cyclic ketones leads to formation of lactams (e.g. 6 — 7) by ring enlargement ... 

A mixture of 9//-tribenzo[a,c,e]cycloheptatrien-9-one oxime (1.36 g, 5 mmol) and PC15 (5.0 g) in anhyd Et20 (50 mL) was stirred at rt for 12 h. The Et20 was evaporated and the residue was treated with H20 (50 mL) and heated on a steam bath for 12 h. The product was recovered as a gray powder by filtration of the cooled solution yield of crude lactam 1.31 g (96%) mp 259-264 C. Recrystallization (CH2C12/ hexane), followed by sublimation (150C/0.1 Torr), gave colorless crystals mp 267 -269 C. 

Not only do oximes undergo the Beckmann rearrangement, but so also do esters of oximes with many acids, organic and inorganic. A side reaction with many substrates is the formation of nitriles (the abnormal Beckmann rearrangement, 17-31). Cyclic ketones can be converted directly to lactams in one laboratory step by... 

It was also of interest to apply such lOOC reactions to formation of carbocyclic rings. Oxime olefins 230 a-e, formed in good yield via reaction of 229 with 0-silyl-a-bromoaldoximes 228 in the presence of F ions, cyclized in a sealed tube at 190 °C to provide 231 a-e (Eq. 24, Table 22) [63]. Reduction of 231a provided amino alcohol 232 a in 68% yield. Amino alcohol 232 e was converted stereo-specifically to the fused -lactam 233. 

Regioselective Beckmann rearrangements were used as key steps in the synthesis of phosphonoalkyl azepinones (Scheme 36) [43b] and in a formal total synthesis of the protein kinase C inhibitor balanol (Scheme 37) the optically active azide 197 derived from cyclohexadiene mono-oxide was converted into ketone 198 in several steps. After preparation of the oxime tosylates 199 (2.3 1 mixture), a Lewis acid mediated regioselective Beckmann rearrangement gave the lactams 200 and 201 in 66% and 9% yield, respectively. Lactam 201 underwent a 3-e im-ination to give additional 200, which served as a key intermediate in a balanol precursor synthesis (Scheme 37) [43 cj. 

The stereochemical use of the Beckmann rearrangement in assigning configuration to ketoximes has already been referred to, and it also has a large-scale application in the synthesis of the textile polymer Nylon-6 from cyclohexanone oxime (78) via the cyclic amide (lactam, 79) ... 

Ozonolysis of alkene 446 in the presence of acetaldehyde afforded diketone 448 through the intermediacy of 447. Ring expansion through Beckmann rearrangement took place when bis-oxime 449 was mesylated and warmed in aqueous tetrahydrofuran (THF). The bis-lactam so formed gave piperidinediol 450 on reduction with lithium aluminium hydride, and this compound was transformed into ( )-sparteine by treatment with triphenylphosphine, CCI4, and triethylamine (Scheme 105) <20050BC1557>. 

The transformation of oximes to lactams (the Beckmann rearrangement) was one of the earliest such acid-catalyzed reactions to be reported with TS-1 (138) and TS-2 (247) catalysts. The rearrangement of cyclohexanone oxime to e-caprolactam proceeds with high selectivity in the presence of TS-1, with high catalyst stability (138,247). 

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