1 -Nitro-3-methylbutane

The nitro compounds, 1-nitro-3-methylbutane and 1-nitro-2-phenylethane, were particularly difficult to identify because they give very weak parent ions with electron ionization (E.I.). However, C.I. mass spectra gave adequate M+1 ions. 

The identification of 1-nitro-3-methylbutane in tomato had been reported previously by Wobben et al. (5) although they had not published any GLC or mass spectral data. None of the other numerous studies of tomato volatiles (of. 3.) had reported finding this compound. It is a relatively prominent component of fresh tomato occurring at a concentration as much as 200 ppb in some varieties such as Ace and related varieties but in other varieties it occurs at lower levels (10-50 ppb). However, it does not seem to be important to fresh tomato aroma because it is a relatively weak odorant with an odor threshold of 150 ppb. 

Nitro-3-methylbutane bears an interesting relationship to two other known volatile components of fresh tomatoes. Isobutyl cyanide and 2-lsobutylthlazole and to the non volatile amino acid leucine. This relationship is shown in Figure 3. They all show a similar skeletal arangement of carbon atoms to the left of the nitrogen. 

CH(N02 XN2 Oj H). Prepd as theNa salt from 4-nitro-2-methylbutane, 2 mols NaO-C2Hs and NO. By treating aq so Ins of the Na salt with Ba(OH)j(or BaCl2), CuS04 and Pb(CHjCOO)2, ppts of explosive Ba-, Cu-and Pb-nitroisoamylnitraminates were obtained Refs l)Beil 1,687 2)W.Traube, Ann 110, (1898)... 

Authentic Samples. Authentic samples of identified compounds were obtained from reliable commercial sources or synthesized by established methods. All samples were purified by GLC separation and their identities verified by mass or infrared spectrometry. 1-Nitro-3-niethylbutane and 1-nitro-2-phenylethane were synthesized according to the method of Kornblum et al.(j ) by the reactions of 1-bromo-3-methylbutane and 2-phenylethylbromide with sodium nitrite in dimethylformamlde and urea. 

C5H10I2 1,2-diiodo-2-methyl butane 66688-52-6 264.15 10.104 2 5699 C5H11N02 1 -nitro-2-methylbutane 3457-57-6 274.22 14.890 2... 

C5H10I2 1,3-diiodo-3-methylbutane 66688-55-9 264.15 10.104 2 5702 C5H11N02 2-nitro-3-methyl butane 2625-35-6 259.22 11.719 2... 

Potatoes 2-Isopropyl-3-methoxypyrazine together with 2,5-dimethylpyrazine (see pyrazines) dominate in raw potatoes. Key compounds in boiled potatoes are meAional and 2-ethyl-3,6-dimethylpyrazine. Tomatoes The highest flavor values in fresh tomatoes are exhibited by (Z)-3- and ( )-2-hexenals (see alkenals), j3- ionone, hexanal (see alkanals), 8-damascenone, I-penten-3-one (CsHgO, Mr 84.12, CAS [1629-58-9], 3-methylbutanal (see alkanals), and 2-isobutylthiazole. The most important flavor components in tomato pulp are dimethyl sulfide, )8-damascenone, )5-ionone, 3-methylbutanal, I-nitro-2-phenylethane (CgH,N02, Mr 151.16, CAS [24330-46-91), eugenol, methional, and 3-methylbutanoic acid. ... 

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