Cyclododecanone, preparation from

Nylon 12 first beeame available on a semieommercial scale in 1963. The monomer, dodecanelactam, is prepared from butadiene by a multistaged reaction. In one proeess butadiene is treated with a Ziegler-type eatalyst system to yield the cyclic trimer, cyclododeca-1, 5, 9-triene. This may then be hydrogenated to give cyelododeeane, which is then subjeeted to direct air oxidation to give a mixture of cyclododecanol and cyclododecanone. Treatment of the mixture with... 

The reaction described is of general synthetic utility for the preparation of a variety of cyclic /3-keto esters from the corresponding ketones. Using this procedure the 2-carbethoxy-cycloalkanones have been prepared from cyclononanone, cyclo-decanone, and cyclododecanone in yields of 85%, 95%, and 90%, respectively. The procedure is simpler and gives much higher yields than other synthetic routes to these systems. 

Cyclododecene may be prepared from 1,5,9-cyclododecatriene by the catalytic reduction with Raney nickel and hydrogen diluted with nitrogen, with nickel sulfide on alumina, with cobalt, iron, or nickel in the presence of thiophene, with palladium on charcoal, with palladimn chloride in the presence of water, with palladium on barium sulfate, with cobalt acetate in the presence of cobalt carbonyl, and with cobalt carbonyl and tri- -butyl phosphine. It may also be obtained from the triene by reduction with lithium and ethylamine, by disproportionation, - by epoxidation followed by isomerization to a ketone and WoliT-Kishner reduction, and from cyclododecanone by the reaction of its hydrazone with sodium hydride. ... 

Dehydrations of dione (61) via the Paal-Knorr synthesis lead to heterophanes (58)-(60) (68TL2181, 69T5357). Dione (61) is readily prepared from cyclododecanone by conventional procedures (64E620). 

The transformation of cyclododecanone via IX/9 to the bicyclic intermediate, IX/10 is possible through an internal enamine reaction. Cleavage of the central ketone bridge gives the 14-membered product IX/11 [3]. This reaction was a key step in the synthesis of ( )-muscone (IX/15), Scheme IX/2, [4]. On treatment with base, the bicyclic intermediate, IX/13, prepared from 2-nitrocyclotri-decanone (IX/12), was quantitatively (R=H) [5] (or in 47 % yield (R=CH3) [4]) converted into the enlarged product IX/14. The retro aldol reaction was not... 

Bicyclo[10.3.0]-A 4S-pentadecen-14-one (25) was prepared from cyclododecanone. Allylation of the... 

Bicyclo[10.3.0]-A -pentadecen-14-one (25) was prepared from cyclododecanone. Allylation of the 3-keto ester (23) and the oxidation of the terminal alkenic bond afforded the 1,4-diketone (24) in 72% yield from the 3-keto ester. Base-catalyzed cyclization and deethoxycarbonylation gave die bicycloketone (25), which was converted to muscone (26 Scheme 7). Thus, this is a method for three-carbon ring expansion. 

Dodecanedioic acid is prepared from cyclododecene (obtained from butadiene) by methods which are entirely analogous to those used to prepare adipic acid from benzene (section 10.2.2(a)). The cyclododecene is reduced to cyclododecane, which is oxidized firstly to a mixture of cyclododecanol and cyclododecanone and then to dodecanedioic acid. Dodecanedioic acid is a colourless crystalline solid, m.p. 129°C. 

These reactions become more realistic if derivatives of a,/3-epoxy ketones are used. These can be easily prepared by oxidation of the corresponding a,/3-unsa-turated ketones with peracids or hydrogen peroxide (Scheme VIII/13). The driving force in studying this kind of reactions is the importance of the economic synthesis of the natural 15-membered ketones, muscone and cyclopentadeca-none, from cyclododecanone, an easy available and inexpensive starting material (Scheme VIII/14) [35] [36]. 

Baeyer-Villiger reaction. This peracid is recommended for large-scale Baeyer-Villigcr oxidation of unreactivc ketones. It is almost as reactive as trifluoropcracetic acid, but is less expensive. The 90% H 0, originally used for in situ preparation of the pcracid can be replaced by the less hazardous 30% H,0,. By suitable modifications, dodccanolide (2) can be prepared in 77% yield from cyclododecanone. 

This method is also useful for preparation of the 2-carbethoxycycloalkanones from cyclononanone, cyctodecanone, and cyclododecanone in yields of 85, 95, and 90%, respectively. 

A mixture of cis- and truns-1-methoxycyclododecenes was prepared in 98% yield from cyclododecanone by a modification of Claison s method of ketal formation. Amberlyst-15 is a superior catalyst for the preparation of enol ethers and acetals. 

Analysis Weigh the flask and calculate the yield of solid cyclododecanone. Determine the melting point of the product. Prepare the semicarbazone (mp 218-219 °C) or oxime (mp 131-132 °C) according to the procedures given in Sections 25.7G and 25.7H. If necessary, recrystallize the derivatives from methanol. Obtain IR and NMR spectra of your starting material and product, and compare them with those of authentic samples (Figs. 16.1-16.4). 

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