Abstract
Synthesis of some new fluoren-9-ones and benzisoxazoles under both thermal and microwave conditions is reported. The prepared products under microwave conditions are obtained with high yields and within shorter reaction times. Reaction of lithiated bromobenzene with aromatic aldehydes
2a
,
b
delivered diarylmethanols
3a
,
b
that were oxidized to
4a,b
. Compound
4a
was cyclized to give methoxyfluoren-9-one
5,
which was demethylated affording hydroxyfluoren-9-one
6
. Compound
4b
was reacted with triethyl phosphite to produce benzisoxazole
10
. On the other hand, reaction of triethyl phosphite with
13a,b
afforded a mixture of phosphoramidates
14a,b
and benzisoxazoles
15a,b
. The structures of the synthesized compounds have been elucidated unambiguously by NMR-spectroscopic methods including HH COSY, HSQC, and HMBC experiments.