Лако-красочные материалы — производство

5.3.2.1. Via One-Carbon Synthons

Triethyl orthoformate or chloroform can react with arene nucleophiles to give triphenylmethanes with three identical aryl groups.5’52’67 In addi­tion, dialkylarylamines, when treated with dialkoxycarbenium tetrafluoro — borates under thermodynamic conditions or with triethyl orthoformate/zinc chloride in ether under anhydrous conditions, give triarylmethanes.68 For example, 4-methoxycarbazole and triethyl orthoformate in the presence of acid catalyst give 44 in 66% yield69 (Scheme 7). In general, phenolic or

arylamino aldehydes or their orthoesters yield a mixture of di — and triaryl — methane compounds. This synthetic method is best used for preparing triarylmethanes.