A chromene compound which contains a skeleton represented by the following formula (1) and has high color optical density at the time of exposure, double peak characteristic, little initial coloration, a practical fading speed and durability.
(wherein R
1
is an electron donor group having a Hammett constant of less than 0, the ring including X is a hetero ring formed together with the 7-position and 8-position carbon atoms, and X is an oxygen atom, sulfur atom or group represented by ═NR
2
directly bonded to the 7-position carbon atom.)
Reactions of diazo ketones with activated unsaturated compounds in the presence of gallium trichloride
作者:R. A. Novikov、Yu. V. Tomilov、O. M. Nefedov
DOI:10.1007/s11172-014-0444-7
日期:2014.2
Diazoacetone reacts with methyl acrylate in the presence of anhydrous GaCl3 to give isomeric methyl 2-acetylcyclopropanecarboxylates rather than pyrazolines obtained from diazo esters or by noncatalytic reactions. In a similar reaction, diazoacetophenone yields methyl 2-benzoylcyclopropanecarboxylates, benzoylmethyl acrylate, and benzoylmethyl 2-benzoylcyclopropanecarboxylate via partial transesterification