Studies on the N-oxides of .PI.-deficient N-heteroaromatics. XXXIV. A novel synthesis of substituted indoles by photochemical ring contraction of 3,1-benzoxazepines.
A novel photochemical ring-contraction reaction of 5-unsubstituted 3, 1-benzoxazepines and their 5-halogeno or carboxyl derivatives to yield 3-formylindoles in an aprotic solvent is reported. This ring contraction was successfully extended to oxazepines having an alkoxycarbonyl function at the 5-position to give the indoles having this function at the 3-position. Though most of the oxazepines underwent the ring-contraction reaction only on irradiation at 254 nm, 5-carboxy derivatives or their esters afforded the ring-contraction products even at ≥ 300 nm. The intermediacy of 3H-indole species in these photochemical ring-contraction reactions was demonstrated by the isolation of methyl 3-acetyl-2-phenyl-3H-indole-3-carboxylate during the photolysis of methyl 4-methyl-2-phenyl-3, 1-benzoxazepine-5-carboxylate. It was found that this 3H-indole afforded methyl 6-and 4-acetyl-2-phenyl-indole-3-carboxylates upon further irradiation. The mechanism of this acetyl migration is discussed based on the result of the photochemical acetyl migration of methyl 1-acetyl-2-phenylindole-3-carboxylate.
The present invention relates to the indole derivatives of formula (I), wherein R1- R6 and X are defined in the claims and optical antipodes or racemates and/or salts thereof which are selective antagonists of bradykinin B1 to process for producing these compounds, pharmacological compositions containing them and to their use in therapy or prevention of painful and inflammatory conditions.
The present invention relates to the indole derivatives of formula (I), wherein R
1
-R
6
and X are defined in the claims and optical antipodes or racemates and/or salts thereof which are selective antagonists of bradykinin B1 to process for producing these compounds, pharmacological compositions containing them and to their use in therapy or prevention of painful and inflammatory conditions.