Nonanedione

Submitted by K. Gerald Hampton, Thomas M. Harris, and Charles R. Hauser 1 Checked by Eugene Gosselink and Peter Yates 

Caution This -preparation should he carried out in a hood to avoid exposure to ammonia. 

A suspension of sodium amide (1.10 moles) in liquid ammonia is prepared in a 1-1. three-necked flask equipped with an air condenser (Note 1), a ball-sealed mechanical stirrer, and a glass stopper. In the preparation of this reagent commercial anhydrous liquid ammonia (800 ml.) is introduced from a cylinder through an inlet tube. To the stirred ammonia is added a small piece of sodium. After the appearance of a blue color a few 

The checkers used a dry ice condenser during the introduction of ammonia to the reaction flask and replaced it with an air condenser before the addition of sodium. 

3 Eastman Organic Chemicals 2,4-pentanedione was dried over potassium carbonate and distilled before use, the fraction boiling at 133-135° at atmospheric pressure being used. 

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Nonanedione, another 1,3-difunctional target molecule, may be obtained from the reaction of hexanoyl chloride with acetonide anion (disconnection 1). The 2,4-dioxo substitution pattern, however, is already present in inexpensive, symmetrical acetylacetone (2,4-pentanedione). Disconnection 2 would therefore offer a tempting alternative. A problem arises because of the acidity of protons at C-3 of acetylacetone. This, however, would probably not be a serious obstacle if one produces the dianion with strong base, since the strongly basic terminal carbanion would be a much more reactive nucleophile than the central one (K.G. Hampton, 1973 see p. 9f.). 

N-Nitroso N phenylglycine, 46, 96 reaction with acetic anhydride to yield 3 phenylsydnone, 46, 96 Nitrosyl chloride, addition to bicyclo-[2 2 ljhepta 2,5 diene, 46, 75 2,4-Nonanedione, 47, 92 Nonane, 1,1,3 trichloro-, 46,104 Nortricyclanol, 46, 74 oxidation by chromic acid, 46, 78 Nortricyclanone, 46, 77 Nortncj clyl acetate 46, 74 frombicyclo[2 2 ljhepta 2,5 dieneand acetic acid, 46, 74 saponification of, 46, 75... 

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 45, 71 Sodium amide, in alkylation of ethyl phenylacetate w ith (2-bromo-ethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1 bromobutane to give 2,4-nonanedione, 47, 92 Sodium 2 ammobenzenesulfinate, from reduction of 2 mtrobenzenesul-finic acid, 47, 5... 

Sodium amide, in alkylation, of di-phenylmethane, 48, 80 of ethyl phenylacetate with (2-bromoethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1-bromobutane to give 2,4-nonanedione, 47, 92... 

The structure of [Fe(MeCOCOCHCOMe)3] has been determined/ of [Fe(acac)]3 redetermined at 20K (Fe—0=1.977 to 2.004A).Iron(III) forms mainly 1 1 and 1 3 complexes with acetylacetone and with benzoylacetone in DMF their reduction has been monitored electrochem-ically. " Solubilities, and derived transfer chemical potentials, of [Fe(acac)3] in various binary aqueous solvent mixtures give a measure of preferential solvation. Rate constants have been determined, at 283 K, for formation of 2,4-octanedione and 2,4-nonanedione complexes of iron(III). ... 

This procedure represents a novel, convenient, and fairly general method for preparing y-aryl-/3-diketones. By this method the submitters have phenylated the dianion of 1-phenyl-1,3-butanedione (61%), 2,4-heptanedione (98%), 2,4-nonanedione (78%), 2,4-tridecanedione (53%), and 3,5-heptanedione (50%).6 Substituted diaryliodonium salts have also been used to produce l-(4-chlorophenyl)-2,4-pentadione (44%), 4-(4-methyl-phenyl)-l-phenyl-l,3-butanedione (44%), and l-(4-methyl-phenyl)-2,4-nonanedione (21%).6 Under these conditions no more than a trace, if any, of arylation at the a-position of the /3-diketones was observed by gas chromatography analysis. 

Methyl-2,4-nonanedione Soy beans Tea Butter Furanoid fatty acids [80]... 

The method described is that of Hampton, Harris, and Hauser2 and is an improvement over the earlier procedures 4 of Hauser and co-workers, which employed potassium amide. 2,4-Nonanedione has been prepared by the condensation of ethyl caproate with acetone in the presence of sodium hydride (54-80%), 5,6 and by the acylation of ethyl acetoacetate followed by cleavage and decarboxylation (51%).7 Other preparations include the acetylation of 2-heptanone with ethyl acetate and... 

Green tea (Sencha) (Z)-1,5-Octadien-3-one (129), 4-methyl-4-sulfanyl-2-pentanone (130), methional, (2E,6Z)-2,6-nonadienal, 3-methyl-2,4-nonanedione (131), methyl ep/ -jasmonate, indole 148... 

Black tea (Darjeeling) (R)-Linalool, geraniol, (2 ,4 ,6Z)-2,4,6-nonatrienal, /3-damascenone, 2-methylbutanal, 2-methylpropanal, 3-methylbutanal, 3-methyl-2,4-nonanedione, (2f,6Z)-2,6-nonadienal 149... 

Figure 6. Proposed mechanism for the photogeneration of 3-methyl-2,4-nonanedione (56).

The odorants of green tea, powder and brew, are detailed in Table 6.54. 3-Methyl-2,4-nonanedione (no. 3) is of special interest among the odorants showing high OAV. It smells green and strawy and was detected at first in soybean oil showing a light-induced off-flavour (Table 6.55). Precursors of no. 3 are furanoid fatty acids [23, 107[. 

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