Condensation, of cyclohexanone, with

The addition of phenylisocyanate to aldehyde-derived enamines resulted in the formation of aminobutyrolactams (438,439). As aminal derivatives these produets can be hydrolyzed to the linear aldehyde amides and thus furnish a route to derivatives of the synthetically valuable malonaldehyde-acid system. With this class of reactions, a second acylation on nitrogen becomes possible and the six-membered cyclization products have been reported (440). Closely related to the reactions of enamines with isocyanates is the condensation of cyclohexanone with urea in base (441). 

Fluoride-catalyzed condensation of cyclohexanone with tetra(isothiocyanate)silane 558 in the presence of BU4NF or BusSnF and (Me3Si)2S04 559 affords, in 98% yield, the unsaturated isothiocyanate 560 and Si02 [130]. 

Condensation, of cyclohexanone, with dimethylformamide-phosphorus oxychloride, 46,18 with triethyl phosphonoacetate to yield ethyl cyclohexylideneace-tate, 46, 44... 

Ethyl /3,/3-pentamethyleneglycidate has been prepared in 65% yield by the condensation of cyclohexanone with ethyl chloro-acetate in the presence of sodium ethoxide,4 and in 50% yield in the presence of sodium in xylene.6 The present procedure employs potassium (erZ-butoxide as the condensing agent.3... 

An important variation on the Claisen condensation is to use a ketone as the anionic reagent. This often works well because ketones usually are more acidic than simple esters and the base-induced self-condensation of ketones (aldol addition) is thermodynamically unfavorable (Section 17-3C). A typical example is the condensation of cyclohexanone with diethyl ethanedioate (diethyl oxalate) ... 

Formyitttion of ketones. The condensation of cyclohexanone with ethyl formate in the presence of either sodium ethoxide or sodium hydride gives a product which can be described as 2-hydroxymethylenecyclohcxanone (I) or the tautomer 2-Tormylcyclohexanone (2) for simplicity Ihe pwcess is described us a formylation. In the procedure cited, formylulion was followed by reaction wllfr hydru/ine to... 

This triethanolamine procedure was used also in a synthesis of docosanedioiC acid starting with the condensation of cyclohexanone with morpholine to form 1 morpholino-1-cyclohexene (1), and acylation of this enamine with sebacoyl chlorid ... 

Robinson annellation reaction. Formation of six-membered-ring ,(i-iinsaturatcd ketones by condensation of cyclohexanones with methyl vinyl ketone or its equivalents, followed by an intramolecular aldol condensation. 

Condensation, of cyclohexanone, with ethyl chloroacetate, 34, 54 with sodium cyanide and hydrazine, 32, 50... 

Initial condensation of cyclohexanone with orrho-lithiated veratrole, followed by elimination and an ingenious allylic oxidation yielded enone 64, Scheme 5. Michael... 

Prepared by zinc-promoted condensation of cyclohexanones with esters of bromoacetic acid in yields of 60-80% O. Wallach, Ann., 365, 255 (1909). 

Condensation of cyclohexanone with ethyl prolinate 199 under Dean-Stark conditions gave the enaminone 200, which was reduced in three stages to pyrrolizidine 201, Scheme 53 (76CJC1512 78CJC320). 

More commonly, sodium hydride is used as a base for carbonyl condensation reactions. For exarrple, Claisen condensations of ethyl acetate and ethyl isovalerate are effected by sodium hydride. Condensations of cyclohexanone with methyl benzoate and ethyl formate (eq 16) are also facile. Sodium hydride can... 

The unsaturated tetraoxaquaterene (accompanied by linear condensation products) was first synthesized in 18.5% yield by the acid-catalyzed condensation of furan with acetone in the absence of added lithium salts. Other ketones also condensed with furan to give analogous products in 6-12% yield.A corresponding macrocycle was also prepared in 9% yield from pyrrole and cyclohexanone. The macrocyclic ether products have also been obtained by condensation of short linear condensation products having 2, 3, or 4 furan rings with a carbonyl compound. ... 

Kinetic Aldol Condensations of Cyclohexanone Enolates with Aromatic Aldehydes (eq. [18])... 

Ethinamate Ethinamate, 1-ethynylcyclohexanone carbamate (4.3.4), is synthesized by the condensation of acetylene with cyclohexanone and the subsequent transformation of the resnlting carbinol into carbamate by the subsequent reaction with phosgene, and later with ammonia [36,37]. 

Ethyl 1-hydroxycyclohexylacetate has been prepared by the Reformatsky reaction of cyclohexanone with zinc and ethyl bromoacetate (56-71 %)3 and by the condensation of ethyl acetate with cyclohexanone in liquid ammonia using two equivalents of lithium amide (69%).4... 

For conversion of ketones into a,/3-unsaturated aldehydes containing two additional carbon atoms, several multistep processes via ethynyl or vinyl carbinol intermediates have been reported.4-10 Although the overall yields obtained by these routes for the conversion of cyclohexanone into cyclohexylideneacetaldehyde have never exceeded 50%, they were the only useful methods for this type of conversion until the excellent process of Wittig11 appeared. This process consists of normal aldol condensations of ketones with the lithium salt of ethylidenecyclohexylamine and subsequent dehydration and hydrolysis. 

Tetrahydroindoles (1, 2) are prepared by the condensation of cyclohexanone oxime (116) with vinyl chloride in the presence of KOH in a DMSO medium at 90-140°C under atmospheric pressure (Scheme 56) (81MIP1 86ZOR489). 

Structural factors in the reactants and the reaction pH have both been varied to optimize the electrophilic condensation of pyrimidines with cyclic ketones such as N-substituted piperidones and 4-substituted cyclohexanones.185... 

The title 13C-labelled heterocyclic compounds have been synthesized82 to understand better the coal liquification process83, Cyclohexanone-l-13C, 95, has been prepared through the sequence of reactions shown in equation 44. The carbonation of 96 at —78 °C gave 95 in 24-38% yield. At —8°C, the condensation of 95 with excess of Grignard... 

Condensation of the pyrrolidine enamine of cyclohexanone with l,l-dicyano-2,2-dimethylcyclopropane proceeds smoothly in refluxing dry xylene and gives the expected adduct in 76% yield. Recrystallisation of the adduct from 95% ethanol, however, gave a 91% yield of a product which no longer contained the pyrrolidine group but whose spectral data clearly showed the presence of a ketone group and an enaminonitrile function. Hydrolysis of this latter product with phosphoric acid/acetic acid gave 5-(2-oxo-4,4-dimethylcyclopentyl)pentanoic acid in 83% yield. 

Ozonolysis of vinylpyrazine in methanol at — 30° furnishes pyrazine aldehyde in 73% yield.196 Vinylpyrazine undergoes a variety of addition reactions and pyrazylethyl derivatives of amines, ketones, ethyl phenyl acetate, phenylacetonitrile, and acetamide have been obtained.197-199 2-(2-Pyrazylethyl)cyclohexanone (42) has been prepared both by the condensation of vinylpyrazine with cyclohexanone in the presence of sodium metal and by interaction of vinylpyrazine with the pyrrolidine enamine of cyclohexanone followed by hydrolysis.200... 

Cyclohexenylacetonitrile has been prepared by the decarboxylation of cyclohexylidenecyanoacetic acid 4-5 by the dehydration of 1-cyclohexenylacetamide 5 by the condensation of cyclohexanone and cyanoacetic acid in the presence of piperidine 6 by the condensation of cyclohexanone and ethyl cyano-acetate in the presence of sodium ethoxide 4-7 and by the condensation of cyclohexanone and cyanoacetic acid in the presence of ammonium acetate followed by decarboxylation.8 Ammonium acetate also has been used as a catalyst for the condensation of ketones with ethyl cyanoacetate.3-9... 

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