No abstract

The reactions of 2-(N-ary1formimidoyl)pyridines with a number of active methylene compounds have been investigated. Reduction of the products gave octahydroindolizine derivatives, some of which were also prepared by other routes. The interaction of 2-(N-phenylforrnimidoyl) pyridine and diethyl succinate gave an octahydropyrrolo [3,4-c] pyrrole.

Polyaza-and oxapolyaza-benzonaphthanthracenes, isosteric with tricycloquinazoline, have been synthesised.Various eliminations from appropriately substituted arylpolyazabenzanthracenes readily gave these hexacyclic compounds. The oxadiaza analogue is intensely carcinogenic. Correlation of their activities with previously described isomers and isosteres shows the critical significance of certain symmetry factors for activity. THE carcinogen, tricycloquinazoline (I) has a unique trigonal symmetry; loss of symmetry by replacement of the 5 , 10, or 15 nitrogen by methine or reorganisation of the structure into the tetra-azanaphthonaphthacene N 0 N (11) or its isostere (111) abolishes activity. To obtain further evidence on this symmetry factor, isomeric and isosteric analogues of tricycloquinazoline with modifications at positions 4a, 5, and 14c have been synthesised. N-Phenyl-o-nitrobenzimidoyl chloride condensed with diethyl sodiomalonate to yield diethyl N-phenylo-nitrobenzimidoylmalonate, which with phosphoryl chloride furnished the chloroquinoline (IV; R1 = CO,Et, R2 = C1, R3 = NO,). The production of the last compound from the hydroxyquinoline (IV; R1 = CO,Et, R2 = OH, R3 = NO,), readily formed by thermal cyclisation of the benzimidoylmalonate, was less efficient. The chloroquinoline (IV; R 1 = CO,Et, R 2 = C1, R3 = NO,) reacted preferentially with amines at chlorine rather than at the ester; thus when heated with aniline, it gave the anilino-ester (IV; R1 = CO,Et, R2 = 1 Part XIX, M. W. Partridge, S. A. Slorach, and H.

An investigation of the mass spectral behaviour of the title compounds is reported. Two processes have been studied by deuterium labelling. One, which occurs with all three ring systems, results in the loss of a C,H, radical, whilst the other, which occurs only in the dibenzothiazocine, leads to the loss of a C6H6N radical.

Three of the four possible racemic forms of ethyl octahydro-3-methylindolizine-2-carboxylate have been isolated, and their stereochemistry has been elucidated.