Heptan-2-one

Cyclopropylcarbinyl radicals (5) are alkyl radicals but they undergo rapid ring opening to give butenyl radicals." The rate constant for this process has been measured by picosecond radical kinetic techniques to be in the range of 10 M s for the parent to lO Af s for substituted derivatives. This process has been observed in bicyclo[4.1,0]heptan-4-ones. ... 

Synonyms 4-heptanone DPK propyl ketone butyrone heptan-4-one... 

Only a few examples exist where diazocyclopropane has been used for annulations via oxa-spiropentanes. 1,3-Bisdiazopropane reacted with cyclohexanone, probably by previous formation of diazocyclopropane, to give spiro[2.6]nonan-4-one (2, 27%) and spiro[3.5]nonan-l-one (1, 10%).82 83 The latter was formed from the corresponding oxaspiropentane.83 Diazocyclopropane, as generated from /V-cyclopropyl-iV-nitrosourea or /V-cyclopropyl-iV-nitrosocarba-mate, behaves similarly. It reacts with cyclobutanone to give spiro[2.4]heptan-4-one (4, 80%) and spiro[3.3]heptan-l-one (3, 7%).84... 

Although cycloreversion is the dominant route in 2,7,7-trimethylbicyclo[3.1.1]heptane (pinane) pyrolysis, appropriate substituents on the pinane skeleton can in fact retard cycloreversion, thereby allowing formation of more products through carbon bond rupture and hydrogen transfer.100,102,106 In support of this feature it has been found that the pyrolysis of isoverbanone [(lS,2JR,5 )-2,6,6-trimethylbicyclo[3.1.1]heptan-4-one, 10] at 580°C gives, in addition to unreacted starting material, a mixture of five components, from which the major product m-3-methyl-4-isopropenylcyclohexanone (15) was isolated in 20% yield. The other products are 2,6-dimethylocta-2,7-dien-4-one (12 15%) and 5,7-dimethylocta-l,6-dien-3-one... 

Place 100 g (1.53 mol) of zinc wool in a 1-litre three-necked flask and amalgamate it in accordance with Method 1 in Section 4.2.50, p. 467. Fit the flask with a sealed stirrer unit, an efficient double surface condenser and a lead-in tube dipping almost to the bottom of the flask for the introduction of hydrogen chloride gas (compare Figs 4.4 and 2.59) insert an empty wash bottle between the hydrogen chloride generator and the flask. Introduce through the condenser 250 ml of concentrated hydrochloric acid and 50 ml of water, set the stirrer in motion and then add 40 g (0.35 mol) of heptan-4-one (Expt... 

Dipropyl ketoxime (heptan-4-one oxime). Heat a mixture of 20 g (0.18 mol) of heptan-4-one, 17 g (0.25 mol) of hydroxylamine hydrochloride, 19.6 g (20 ml, 0.25 mol) of pyridine and 150 ml of ethanol under reflux for 1 hour in a 500-ml round-bottomed flask. Rearrange the condenser for downward distillation and remove the ethanol on the water bath. Allow the residue in the flask to cool and add 150 ml of water. Extract the oxime with three 50 ml portions of ether. Wash the combined extracts with water and dry over magnesium sulphate. Remove the ether on the rotary evaporator and distil the residue at atmospheric pressure. Collect the fraction having b.p. 192-195 °C the yield is 18.2g (80%). The oxime shows infrared absorptions at 3300 cm-1 (O—H stretch) and 1655 cm-1 (C=N stretch). 

A simple but surprising example of using an available starting material is the synthesis of 1,7-difunctionalised heptan-4-ones 86 and 88, each having two 1,4-diX relationships.13 The dihaloketone 86 was made from the aldol dimer 85 of butyrolactone 75, as described in chapter 19, where compound 85 was compound 26. The two 1,4-diX relationships in 86 can be seen in the intermediate 85 which has lost CO2 on its way to 86. 

SYNS BUTYRONE (DOT) GBL HEPTAN-4-ONE 4-HEPTANONE PROPYL KETONE... 

The recently described sulphur ylide diphenylsulphonium cyclopropylide (172), which converts saturated ketones into spirocyclobutanones, reacted with a steroidal 4,6-dien-3-one in a more complex manner. Two moles of the reagent were incorporated to give the spiro[2,4]heptan-4-one (173) and the epimer at the C-3 position of the steroid. Scheme 7 illustrates the likely reaction path. ... 

Hydrolysis of ( —)-methyl (15,3S)-(2,2-dimethyl-3-tosyloxycyclobutyl)acetate, obtained by a stereocontrolled route from (-f )-a-pinene, with zinc(II) acetate in aqueous dimethoxyethane at 80 °C leads to optically active 5-lactone ( —)-(lS,65)-2,2-dimethyl-3-oxabicyclo[4.1.0]heptan-4-one (1) in 62% yield.In addition to this cyclopropane derivative, a carboxylic acid was isolated which on treatment with diazomethane gave (-f )-methyl (5,5-dimethyl-2-tetrahydrofuryl)acetate (2). 

Octahydronaphthalenones (e.g. 15, 17, 19, 21, 23 ) containing a 3-methylene-cyclohexanone unit undergo oxa-di-Tt-methane rearrangement to products containing a spiro[2.4]heptan-4-one subunit. ... 

In order to relate these observations to the extensive information available on the mechanistic and stereochemical consequences of solvolytic tosyloxycydobutane rearrangements, the hydrolysis was performed in aqueous 1,2-dimethoxyethane at 80°C. The optically active (5-lactone ( —)-(15 ,65)-2,2-dimethyl-3-oxabicyclo[4.1.0]heptan-4-one (21) was isolated in 60% yield as the only neutral component. By acidification of the remaining aqueous phase, extraction, and methylation with diazomethane, (-h )-methyl 5,5-dimethyltetrahydrofurylacetate (22) was obtained. ... 

In contrast to methylenecyclopropane, bicyclopropylidene reacted with singlet oxygen generated photochemically. The reaction products were 7-oxadispiro[2.0.2.1]heptane and spiro[2.3]hexan-4-one (ratio 10 6). Both compounds were also obtained by reacting ozone with bicyclopropylidene, together with a third product, which was identified as 7-oxaspiro-[2.4]heptan-4-one (relative amount 67%). °... 

When bicyclopropylidene reacted with chlorosulfonyl isocyanate the ) -lactam 17 resulting from [2 + 2] cycloaddition was a minor product. The main product was 5-chlorosulfonyl-7-methylene-5-azaspiro[2.4]heptan-4-one (16). ... 

Dihydrothiazines may be prepared by the action of elemental sulfur and aziridine upon ketones " the outcome of the reaction is markedly dependent upon the structure of the ketone. Thus with symmetrical ketones of type 62, e.g., pentan-3-one, heptan-4-one, cyclopentanone, cyclohexanone, and cyclooctanone, dihydrothiazines of type 63 were obtained in high yields symmetrical thiazolidines of type 64 were also formed as minor by-products. 

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