Naphthalene-1,4,5-triol

A mixture of cis- and trart5-l,2-dimethylacenaphthene-l,2-diol dissolved in acetic acid is oxidized with chromium trioxide to 1,8-diacetyl-naphthalene in 89% yield [5SS]. The treatment of 17p,17ap-dimethyl-D-homoandrostane-33,17ct,17aa-triol 33-acetate with chromium trioxide or with sodium bismuthate yields 33-acetoxy-17,17a-dimethyl-17,17a-seco-homoandrostane-17,17a-dione (equation 305) [482. ... 

The close relationship of Bulgaria and Daldinia with Hypoxylon in the Xylariaceae is illustrated by the occurrence in some Hypoxylon species of perylenequinones and their relatives (Table 22). The structure of hypoxylone (269), the main pigment of the dark purple carpophores of Hypoxylon sclerophaeum collected in French Guyana, followed from analysis of the and C-n.m.r. spectra and comparison with model systems 107). The naphthyl-naphthoquinone structure of hypoxylone suggests oxidative coupling between naphthalene-1,8-diol (258) and naphthalene-1,4,5-triol. 

However it is also established that the commonly used diphenylmethane and naphthalene diisocyanate-based elastomers are frequently chain-extended with glycols. Table 3.12 contrasts the effects of diamine and glycol chain extenders with a toluene diisocyanate/polyether-based prepolymer, Adiprene LI00. With the unsymmetrical diisocyanates, such as TDI and MDI, polyol chain extenders give elastomers of poorer properties than diamines, and it is usually desirable to introduce additional crosslinking into diol-extender elastomers by the use of a proportion of a triol such as... 

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