L-d-2 METHYLBUTANAL

C. l-d-2-Methylbutanal. A 1-1. three-necked round-bottomed flask is equipped with a dropping funnel, a gas inlet tube for steam, and a Dean-Stark trap to which is attached a condenser through which acetone cooled to —15° is circulated (Note 15). A solution of 50.4 g. (0.40 mole) of oxalic acid dihydrate in 200 ml. of water is added to the flask, and the solution is heated at reflux. Steam is introduced into the flask, and when some begins to condense,in the Dean-Stark trap, the distilled aldimine from part B is added dropwise from the funnel. The aldehyde and water collect in the trap, and the water layer is periodically removed. After the distillation of the aldehyde is complete, the product is drained from the trap, and the water layer is separated... 

Absence of peroxides (b) 2-bromo-2-methylbutane (c) 2-bromobutane (d) 1-bromo-l-ethylcyclohexane. Presence of peroxides (b) l-bromo-2-methylbutane (c) 2-bromobutane (d) (l-bromoethyl)cyclohexane. 

The absolute configuration is S, and thus the compound is (5 )-(+)-l-bromo-2-methylbutane. (d ) The highest ranked substituent at the stereogenic center of 3-buten-2-ol is the hydroxyl group, and the lowest ranked substituent is H. Of the remaining two, vinyl outranks methyl. 

Properties Straw- to purple-colored liquid. D 0.88 (20C), 95% distills between 85 and 109C, wt/gal 7.33 lb, refr index (20C) 1.406. Insoluble in water water azeotrope at 77-82C approximately 90% CjHjjCI, miscible with alcohol and ether. Flash p 38F (3.3C) (OC). Components 1-chloropentane, bp 107.8C 2-chloropentane, bp 96.7C 3-chloropen-tane, bp 97.3C l-chloro-2-methylbutane, bp 99.9C l-chloro-3-methylbutane, bp 98.8C 3-chloro-2-methylbutane, bp 93.0C 2-chloro-2-methylbutane, bp 86.0C. 

Scheme 6. The monochlorination products of 2-methylbutane at 300°C. Hydrogen chloride (HCI) is also obtained. The products are separable. As shown by gas chromatography, the monochlorination products l-chloro-2-methylbutane (A), l-chloro-3-methylbutane (B), 2-chloro-2-methylbutane (C), and 2-chloro-3-methylbutane (D) are actually obtained in the following percent yields 30% A 15% B 22% C and 33% D.

Indenopyrene, see Indeno[l,2,3-crf pyrene l//-Indole, see Indole Indolene, see Indoline Inexit, see Lindane Inhibisol, see 1,1,1-Trichloroethane Insecticide 497, see Dieldrin Insecticide 4049, see Malathion Insectophene, see a-Endosulfan, p-Endosulfan Intox 8, see Chlordane Inverton 245, see 2,4,5-T lodomethane, see Methyl iodide IP, see Indeno[l,2,3-crf pyrene IP3, see Isoamyl alcohol Ipaner, see 2,4-D IPE, see Isopropyl ether IPH, see Phenol Ipersan, see Trifluralin Iphanon, see Camphor Isceon 11, see Trichlorofluoromethane Isceon 122, see Dichlorodifluoromethane Iscobrome, see Methyl bromide Iscobrome D, see Ethylene dibromide Isoacetophorone, see Isophorone a-Isoamylene, see 3-Methyl-l-butene Isoamyl ethanoate, see Isoamyl acetate Isoamylhydride, see 2-Methylbutane Isoamylol, see Isoamyl alcohol Isobac, see 2,4-Dichlorophenol Isobenzofuran-l,3-dione, see Phthalic anhydride 1,3-Isobenzofurandione, see Phthalic anhydride IsoBuAc, see Isobutyl acetate IsoBuBz, see Isobutylbenzene Isobutane, see 2-Methylpropane Isobutanol, see Isobutyl alcohol Isobutene, see 2-Methylpropene Isobutenyl methyl ketone, see Mesityl oxide Isobutyl carbinol, see Isoamyl alcohol Isobutylene, see 2-Methylpropene Isobutylethylene, see 4-Methyl-l-pentene Isobutyl ketone, see Diisobutyl ketone Isobutyl methyl ketone, see 4-Methyl-2-pentanone Isobutyltrimethylmethane, see 2,2,4-Trimethylpentane Isocumene, see Propylbenzene Isocyanatomethane, see Methyl isocyanate Isocyanic acid, methyl ester, see Methyl isocyanate Isocyanic acid, methylphenylene ester, see 2,4-Toluene-diisocyanate... 

Problem 4.32 Give topological structural formulas for (a) propane, (h) butane, (c) isobutane, (d) 2,2-dimethylpropane, (e) 2,3-dimethylbutane, (/), 3-ethylpentane, (g) l-chloro-3-methylbutane, (h) 2,3-dichloro-2-methylpentane, (/) 2-chloro-2,4,4-trimethylpentane. -4... 

It has been found that meso- and D,L-2,3-butanediols give different mixtures of 2-butanone and 2-methylpropanal on treatment with sulfuric acid. From consideration of the influence of steric hindrance on the detailed mechanism of the reaction, predict which butanediol diastereomer will give more 2-methylbutanal. (The vital stage of the reaction is likely to be where the migrating group is halfway between the old and new positions.)... 

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