2-Methyl-3-heptanol preparation

The IR spectrum of 2-methyl-3-heptanol prepared by the procedure of Part C sometimes shows a band at 1720 cm. Give a possible source for this absorption. 

Heptanol-2 has been prepared by the action of w-amyl magnesium bromide on acetaldehyde,1 and by the reduction of methyl w-amyl ketone in alcoholic solution by means of sodium.2... 

Sn2 Reactions with epoxides and aziridines are also synthetically useful. An example of epoxide cleavage with an organocopper reagent with sp carbon moieties is the enantioselective synthesis of (3S, 4S)-4-methyl-3-heptanol (53), an elm bark beetle (Scolytus multistriatus) pheromone [42]. The chiral epoxy oxazolidine 51 [43], prepared from (R)-phenylglycinol, reacted with a propylmagnesium bromide-derived cuprate at —70 °C to afford the oxazolidine 52 in 74% yield (Scheme 9.12). Compound 52 was converted into the target molecular 53 by conventional procedures. 

Methyl-3-heptanol, stereoselective preparation, 9, 12 Methylidyne cubane, via Ti(IV) complexes, 4, 407 <7-Methyl-(tj5-indenyl)chromium tricarbonyl, rearrangement,... 

Blight M. M., Wadhams L. J. and Wenham M. J. (1979b) The stereoisomeric composition of the 4-methyl-3-heptanol produced by Scolytus scolytus and the preparation and biological activity of the four synthetic stereoisomers. Insect Biochem. 9, 525-533. 

A convenient procedure for the reduction of small amounts of ketones involves the periodic addition of small pieces of sodium to a slowly stirred mixture of an ethereal or benzene solution of the ketone and water or a concentrated solution of sodium carbonate. Sodium and alcohol are used for the conversion of methyl n-amyl ketone to 2-heptanol (65%). These reagents are used to prepare secondary alcohols from olefinic ketones obtained by the aldol condensation. Benzophenone and related compounds are reduced by zinc dust and sodium hydroxide, magnesium and methanol, and sodium amalgam. With the last reagent the reaction has been shown to take place through the intermediate sodium ketyl, (C,H,)jCONa. 

The synthesis shown above can be modified for preparation of 4-alkylbutenolides (8) by reduction of the acetylenic acid with quinoline-poisoned catalyst (equation II). The optically active butenolides have been used for a synthesis of optically pure enantiomers of threo- and eryfAro-4-methyl-3-heptanols.2... 

The derivatization of 6-amino-2-methyl-2-heptanol (heptaminol) with 4-N,N -dimethylaminoazobenzene-4 -isothiocyanate was used for the HPLC determination of this amino compound in pharmaceutical preparations [63,64]. Labelling with p-phenylbenzoyl isothiocyanate [65] may also be a good technique for the HPLC determination of amines. 

Reversal of the order of introduction of the two alkyl groups was then tested. Starting from 29 it was straightforward to prepare DIPED (l-chloroethyl)boronate (30) and convert it into the 1-methylbutyl intermediate 31 by treatment with propylmag-nesium chloride (Scheme 8.6). (Dichloromethyl)lithium insertion and ethylation readily yielded 32, which was oxidized to (3R,4S)-4-methyl-3-heptanol (33) (99.8% di-astereopurity), which is the trail pheromone of the southeast Asian ponerine ant Lep-togenys diminuta [13]. The pheromone activity of 33 was 500 times greater than that of any of the other stereoisomers [31]. 

Ichikawa A, Ono H. Preparation of single-enantiomer 2-methyl-4-heptanol, a pheromone of Metamasius hemipterus, using (5)-2-methoxy-2-(l-naphthyl)propionic acid. J. Ckro-matogr. A 2006 1117 38. ... 

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