Montanine, coccinine, and manthine are shown to be Amaryllidaceae alkaloids derived from a new ring system, 5,lime thanomorphanthridine. Degradative and synthetic evidence establishes montanine, coccinine, and manthine as XI,

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A useful n.m.r. technique for the detection, estimation, and characterization of N-methyl groups is described. The method depends on the decreased shielding of Nb,,i,-methyl protons when the solvent is changed from deuterochloroform to perdeuteroacetic (PDA) (or acetic) acid t o trifluoroacetic acid (TFA). The decreased shielding results in a downfield shift of the N-methyl resonance of ca. 0.3-1.3 p.p.m. depending on the type of amine. Most N-methyl groups on neutral nitrogen atoms show little movement. For the majority of aliphatic amines in trifluoroacetic acid the NH exchange rate is slow enough a t 38" to permit observation of coupling of H(N) with the N-methyl protons, and thus determination of whether the amine is secondary or tertiary. In some cases information can be obtained about methylene and methine groups attached t o basic nitrogen. In acid solution compounds with basic nitrogen attached to, or part of, an aromatic ring show considerable shift of the aromatic proton resonance signals to lower magnetic field. Combination of the n.m.r. technique with the Herzig-Meyer analysis can also reveal the number of methyl groups attached to neutral nitrogen.

. J. Chem. 54, 1372Chem. 54, (1976. intramolecular displacement by hydroxyl on the 1,2-epoxide group under basic or neutral conditions has been studied for seven of the stereoisomeric 1,2-diols derived by oxidation of the exocyclic double bond of 1. In six of the examples (the seventh is ambiguous) the single or largely predominant product is that one of the less strained cis-fused isomers which has the fewer unfavourable steric interactions leading to it, without regard to whether the displacement occurs at the secondary or tertiary epoxide carbon.V. SRIN~VASAN et E. W. WARNHOFF. Call. J. Chem. 54, 1372Chem. 54, (1976.O n a CtudiC le delacement intramolkulaire par un hydroxyle du groupe Cpoxyde-1,2; ces etudes ont Ct C effectuCes dans des conditions neutres ou basiques utilisant sept diols-1,2 sttrCoisomkres obtenus par oxydation de la double liaison exocyclique de 1. Dans six des exemples, (le septikme est ambigu) le seul produit ou le produit largement predominant est I'isomkre, attache par une jonction cis, qui est le moins tendu; I'etat de transition conduisant a c e composE prCsente moins d'interactions stCriques non favorables que la rCactioll de deplacement se produise au niveau des carbones secondaire ou tertiaire de I'Cpoxyde.[Traduit par le journal] Some time ago it was shown that basecatalyzed intramolecular displacement in the caryophyllene oxidodiol 10 led exclusively to attack at the tertiary (rather than the secondary) carbon of the oxide to produce glycol 17 (1). It was pointed out that this reaction, if applied to other stereoisomers of 10, provided a means of probing the relative importance of various factors in an intramolecular SN2 reaction of an epoxide. Caryophyllene is a convenient molecule because three of the four epoxide stereoisomers of 1 were known, both possible configurations of the hydroxyl group at C-8 were accessible by suitable choice of oxidizing agent, and finally the structure and stereochemistry of the products were easily discernible. These three points are discussed below, followed by the results for specific compounds.The two cis-oxides 6 and 7 and one trans-oxide 3 were known from the work of Barton and co-workers (2) and Ramage and Whitehead (3), and the second trans-oxide of structure 1 has recently been found to be a minor product in the epoxidation of caryophyllene (4). The reaction of each of the four oxides with 0 s 0 4 occurred only from the a-side1 of the molecule, and the resulting 1,2-diol underwent intramolecular cyclization in the reaction medium. With oxides 2 and 7 the reaction of KMn04 also gave a-attack and the same cyclization product as obtained from 0~0 4 .The argument for a-hydroxylation is threefold. First, since the hydroxylation reagents must bond to both carbon atoms of the double bond in a five-membered transition state A, steric effects will be i m p~r t a n t .~ Of the two extreme conformations of the exocyclic methylene group in the two trans-oxides, the one with the methylene down has both faces of the double bond strongly hindered towar...

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