3 -Methyl-2,4-nonanedione

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

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[. 

Soybean oil Beany-strawy 3-Methyl-2,4-nonanedione, 2,3-butanedione [82, 111]... 

Sigrist, I.A. Manzardo, G.G.G. Amado, R. Aroma compounds formed from 3-methyl-2,4-nonanedione under photooxidative conditions. J. Agric. Food Chem. 2003, 51, 3426. 

Pons A, Lavigne V, Darriet P, Dubourdieu D. Determination of 3-methyl-2,4-nonanedione in red wines using methanol chemical ionization ion trap mass spectrometry. J Chromatogr A. 

Methyl-2,4-nonanedione Soybeans, green tea Furanoid fatty acids 39... 

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. 

Shaking of rac-3,4-dihydro-6-methyl-2-(l-oxopropyl)-2/f-pyran with baker s yeast resulted in initial formation of racemic 6-hydroxy-2,7-nonanedione and then by kinetic resolution/ diastereoselective reduction in the production of (67 ,7S)-6,7-dihydroxy-2-nonanone (2) where both relative and absolute configuration had to be determined (see p 470)134. 

Nonanedioic add, 5-hydroxy-2,4,6,8-tetramethyl- diastereoselective lactonization, 168, 327-328 2,4-Nonanedione retro-synthesis, 204 Norbomane etc. See Bicyclo[2.2.1 ] heptane ere. Norphedrine = (/ , S )-a-benzene-methanol, ( + H S)- chiral auxiliary, 61 —, ( ) synthesis, 302 Norgestrel, ( )- total synth., 278 19-Norpregna-1,3,5(10)-trien-2-yne-3,l 7-diol, (17a)- [ethynylestradiofy 62-63 A-Norpregn-3(5)-eri-20-one, 3-methyl- synthesis, 91-92, 279-280 Noyori hydrogenation, 102-103, 325-326 SI Nuclease, 242... 

Alkylation of a 1,3-dicarbonyl compound at a flanking methyl or methylene group instead of at the doubly activated C-2 position does not usually take place to any significant extent. It can be accomplished selectively and in good yield, however, by way of the corresponding dianion, itself prepared from the dicarbonyl compound and two equivalents of a suitable strong base. For example, 2,4-pentanedione 2 is converted into 2,4-nonanedione by reaction at the more-reactive, less-resonance-stabilized carbanion (1.17). ... 

Condensation reactions on nickel(II) matrices are sensitive to steric effects. X-Ray structm analysis showed [310, 320-328] that H2L263 and its metal complexes are saddle-like, rather than planar. The sources of structural nonplanarity are steric repulsions between methyl groups R, 4 and orr/K>-aromatic protons of the Schiff bases. The increase in the bulk of the groups in these positions hinders macrocyclisation. For example, 3,5-heptanedione, 4,6-nonanedione and 1-phenyl-2,4-pentanedione form cyclic products [Ni(L274)]-[Ni(L276)J, whereas dibenzoyl-methane, 2,6-dimethyl-3,5-heptanedione and 2,2,6,6-tetramethyl-2,5-heptanedione do not give macrocyclic compounds in the presence of nickel(II) and o-phda [300, 320]. In the case of dibenzoylmethane, the nickel(II) )ff-diketonate bis-diamine adduct is isolated (Eq. 2.164) [319]. 

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