AROMATIC COMPOUNDS WITH A 3A,6A-DIHYDROFURO[2,3-B]FURAN MOIETY .2. ALKYLATION PRODUCTS OF DIHYDROXYNAPHTHALENES WITH 1,2-DIHYDRONAPHTHO[2,3-B]FURAN-1,2-DIOL AND THEIR STRUCTURE ANALYSES

摘要

The alkylation of 2,3-, 2,6-, and 2,7-dihydroxynaphthalenes (DHN) with 1,2-dihydronaphtho[2,1-b]furan-1,2-diol (1) in an acidic condition gave various products derived from 7a,14c-dihydronaphtho[2,1-b]naphtho[1',2':4,5]furo[3,2-d]furan (2a). The products were characterized mainly by NMR spectroscopy with the help of the MNDO MO method. The reaction proceeds via two steps. The hydroxyl group-substituted 2a first formed depending on the starting DHN. These 2a derivatives reacted with another mole of 1 to give the corresponding products with two 3a,6a-dihydrofuro[2,3-b]furan moieties. The product from 2,7-DHN, however, formed in a poor yield, accompanying an unexpected 2a derivative, due to a severe steric hindrance. Another method to prepare these compounds was examined using new precursors with four hydroxyl groups, corresponding to 1. [References: 28]