SYNTHESIS OF TRANS-15-NORMAL-BUTYL-16-METHYLDIHYDROPYRENE - SYNTHETIC ACCESS TO 1,2,3-TRISUBSTITUTED BENZENE-DERIVATIVES VIA DIRECT ALKYLATION OF 1,3-BIS(4',4'-DIMETHYL-2'-OXAZOLINYL)BENZENE

A convenient general synthesis of 15, 16-dihydropyrenes requires easy access to 1, 2, 3-trisubstituted benzene derivatives having appropriate functionality. It is now shown that isophthalic acid on conversion to l,3-bis(4',4'-dimethyl-2'-oxazolinyl)benzene (1), followed by alkylation of the corresponding anion, gives the 2-alkyl derivatives 3 and 4 in high yield. Similarly, alkylation of the anion of 2, 6-bis(4',4'-dimethyl-2'-oxazolinyl)toluene (3) occurs smoothly to give 2-substituted l, 3-bis(4',4'-dimethyl-2'-oxazolinyl)benzene derivatives (8 or 9). The hydrolysis of 2-π-butyl-l, 3-bis(4',4'-dimethyl-2'-oxazolinyl)benzene (8) to 2-n-butylisophthalic acid and its subsequent conversion to dithiacyclophane 13 followed by a Wittig rearrangement and a Hofmann elimination to give trans-n-butyl-16-methyldihydropyrene (15) are described. © 1978, American Chemical Society. All rights reserved.