In a previous paper (1) we described the tenOxidation of Reissert Compounds dency of various Reissert c o m ~ o u n d s to undergo It is well established that Reissert compounds 1, autoxidation in basic solution and reported that the 3 are readily converted into the corresponding course of the reaction is dependent on the oxygenheteroaromatic nitriles 2, 4 in alkaline solutions ation state of the compound. This has also been (5-10). N O mechanistic interpretation of this proconfirmed by other authors (2). cess has been given, although it has been suggested In this Paper we wish to report the results of our occasionally (9, 10) that the nitriles could have refurther study in this area, particularly concerning sulted from an interaction of Reissert anions with the formation of intermediates in the oxidation of oxygen. Reissert compounds containing the N-benzoyl can be seen from Schemes 1 and 2, Reissert group. We have measured the amount of oxygen compounds derived from isoquinolines 1 and quinused as well a s established the form in which the olines 3 are oxidized t~ isoquinaldonitriles 2 and cyano substitutent is eliminated from dihydro dequinaldonitriles 4, respectively, independently of rivatives. the nature of the N-substituent. The yields are usuFrom the experimental point of view the phaseally high, except for quinoline derivatives, where transfer conditions ( 3 ) 7 or rather the two-phase large amounts of insoluble polymers are formed. catalytic system (4), used for the generation of car1, the case of N-sulfonyl derivatives le, f, these banions proved to be the most convenient method compoun~s could be transformed into isoquinalfor the measurements. he oxygen was taken from donitriles even without the presence of oxygen. the air, the consumed amount being determined Among the products of this reaction corresponding from the difference in volume before and after the sulfinic acid was found (51, which indicates that an reaction. The experiments were carried out under internal red.-ox. process takes place. atmospheric pressure and at room temperature. Only derivatives with the N-benzoyl group could R ~ N R I be used, because N-alkoxycarbonyl derivatives appeared to release volatile components in the CN CN course of oxidation; similarly, the dimethylforYield of 2 mamide sodium hydride procedure, used for the 1 R R' (5%) generation of carbanions, had to be dismissed. We have found that isoquinoline derived Reissert CI H COC6Hs 90 b H COOC2HS 90 compounds la and 5a need only a half-molar equivc H cOCH3 97 alent of oxygen to be oxidized to isoquinaldonitrile d 6.7-OCH~ COOC2Hs 94 and dihydroisocarbostiril, respectively. In the e H 65 product mixtures benzoic acid (90% of theory) and f H S02C6H,CH3 97 hydrogen cyanide (determined as AgCN, 80% of SCHEME I . Oxidation of isoquinoline Reissert compounds in theory) could be found. the two-phase catalytic system.