The present invention relates to compounds of formula I
wherein Ar
1
, Ar
2
, Ar
3
, n, and
R
1
to R
8
are as defined herein and to pharmaceutically suitable acid addition salts, optically pure enantiomers, racemates or diastereomeric mixtures thereof. These compounds are orexin receptor antagonists and may be useful in the treatment of disorders, in which orexin pathways are involved, like sleep disorders.
palladacycles (1 and 2) were synthesized by the aromatic C–H bond activation of N/3-aryl ring. The application of these regioisomers as catalysts to enable the formation of α-alkylated ketones or quinolines with alcohols using a hydrogen borrowing process is evaluated. Experimental results reveal that palladacycle 2 is superior over palladacycle 1 to catalyze the reaction under similar reaction conditions