I was going to synthesize some 7 substituted coumarins starting from
4-salicylaldehydes. The list of substituents would be chosen so that
I would have a coumarin matching each benzene in the Johnson &
Jankowski 13-C NMR catalog.
As happens, students got involved. After a brief tour of literature,
and with some mentoring from me to balance feasibility, interest, and
potential, my students ended up making
3-(2'-Benzimidazolyl)-7-N,N-diethylaminocoumarin using the Christie
synthesis (Christie R.M., Lui, C.H. Dyes and Pigments, 2000, 79, 89
). This is a well known commercial laser dye, and is one of the
They have also made the 3-(2'-Benzimidazolyl)-7-methoxycoumarin using
an adaptation of Christie's synthesis. This may be a novel compound.
I made the 3-(2'-Benzimidazolyl)-coumarin, e.g., the hydrogen
substituent using the same basic procedure.
My next thought was to make a larger scale of
3-(2'-Benzimidazolyl)-7-aminocoumarin, and to diazotize it and put
almost any substituent I wanted in its place.
My thoughts then turned to 4-amino salicylaldehyde or 4-nitro
salicylaldehyde as a starting material. I have had a difficult time
finding the amino compound in the literature, and I thought that was
I am not fluent in synthesis, and this is the first synthesis I've
done in decades, as my specialty is analytical and I am often
concerned with data, electronics, and someone else's product.
I just wondered what gut reactions there are to this approach. The
underlying goal is to have a "synthesis" project that is perceived as
"real chemistry" by students and colleagues, and to acquire a set of
compounds for my own interest in chemometrics.
And, as the subject line indicates, what is known about 4-amino
Paul J. Franklin(moderator - sci.chem.organic.synthesis) [Only registered users see links. ]
Georgia State University <[Only registered users see links. ].edu>