| 摘要 |
Cyclisation of dehydrolinalol (3,7-dimethyl-3-hydroxy-act-6-en-1-yne) comprises operating in presence of polyphosphoric acid. Partic. 2,6,6-trimethyl-2-ethymyl-tetrahydropyran (I) is prepd. using almost catalytic amts. of polyphosphoric acid at 5-50 degrees C; 3,3-dimethyl-1-acetyl-1 lcyclohexene (II) is prepd. using either excess polyphosphoric acid, or almost catalytic amts. at 120-170 degrees C. A mixt. of (I) and (II) is prepd. using catalytic quantities of polyphosphoric acid at 50-120 degrees C. The prods. are used in perfumes or as intermediates to make other perfume prods. The process enables simple sepn of the prods. by distillation which is an advantage over previous processes e.g. using formic acid, which involves costly isolation procedures. Other advantages are higher yields and the fact that only catalytic quantities of polyphosphoric acid are required. |
