Alkoxyl exchange reactions of naphthalene ethers

Abstract

The Journal of Organic Chemistry due to the more stable isomer 2A which seems to make up 87% of the mixture.Of the various conformations which can result from rotation about the single CN bond in ZA, the two most likely to be present in the transition state leading to reduction are shown in the diagrams below. When the tertiary hydrogen lies in the plane of the paper, the attacking hydride ion is more likely to approach the olefinic carbon from below the plane of the paper for the particular enantiomer shown. In this case, the incoming ion encounters the methyl group rather than the bulkier six-carbon chain and the amine is produced as the racemic diastereoisomer. HA second likely conformation for this enantiomer would occur when the tertiary hydrogen and the methyl group are both staggered on either side of the plane of the paper. Then the attacking hydride ion would prefer to approach from above the plane of the paper and so encounter the hydrogen atom rather than the bulkier methyl group. Consequently, the amine would be produced in the meso form when the ketimine is reduced in this conformation. /(CH2)5CH3The observation that 3 is formed as an isomeric mixture containing 627; of the racemate indicates that the first conformation is more favored than the second. Other factors, however, in addition to those described above may well be hvolved. Experimental Section N-(2-0ctyl)methylhexyketimine @).-A solution of 2-octanone (157.5 g, 1.24 mol) and 2-aminooctane (158.9 g,1.24 mol) in toluene (1.5 1.) was refluxed overnight with a Dean-Stark trap in which water (20.2 g, 1.13 mol) was collected. The solvent was evaporated and the residue distilled under nitrogen to give a small forerun of starting materials, bp 45-95' (1 mm), followed by the ketimine (190 g, 62%): bp 96-97' (52 p ) ; n*7~ 1.4414; uv max (isooctane) 245 mp (e 112); ir (liquid film) 1658 cm-l (C=N); nmr (neat) T 6.62 (m, 1, CH-N=C), 7.87 (t, 2, J = 6 He, CHz-C=N), 8.16 and 8.30 (S, 3, CHa=-N) ppm. Analysis by glpc on several different columns showed one peak. Bis( 1-methy1heptyl)amine (3).-N-(2-0ctyl)methylhexylketimine (150.0 g, 0.772 mol) was added to a stirred solution of lithium aluminum hydride (29.3 g, 0.772 mol) in tetrahydrofuran (1 1.) at room temperature under a nitrogen atmosphere. After refluxing for 24 hr, the metal complex was decomposed by treatment with aqueous base in the usual manner,8 the resulting susAnal. Calcd for ClsHaN: N, 5.85. Found: N, 5.70.During the course of our work on the photooxidation of aromatic systems* we had occasion to prepare 1,2,4 trimethoxynaphthalene. In order to do this we hydrolyzed 1,4diacetoxy-2-meth~xynaphthalene~ (1) with (1) To whom all communications should be addressed.