Notestalline hydrochloride, mp 298-300°dec (lit.7 mp 300°d ec), M26d (EtOH) +207°.(+)-Nandigerine (10) from (+;-A7-Methylnandigerine (8).-The usual conditions afforded 10 (22% from 8), isolated as the crystalline hydrochloride, mp 242-245°dec (lit.7 mp 245-247°d ec), [<*] 26d (EtOH) +240°.( + )-Hernovine ( 11) from (+ )-A7-Methylhemovine ( 9).-The usual conditions afforded 11 (18% from 9) as crystals, mp 235-237°dec (lit.7 mp 236-240°d ec), [a] 26d (EtOH) +253°.Reaction of A7-Oxide 2 with Sulfur Dioxide in Methanol-Benzene.-Dried A7-oxide 2 (50 mg) was dissolved in 1:1 methanol-benzene (20 ml) and S02 was passed into the mixture for 0.5 hr. Aqueous hydrochloric acid (2 N, 10 ml) was added and the solution was refluxed for 3 hr. Basification with ammonia, followed by chloroform extraction, gave a crude product (40 mg),shown by tic to contain only nuciferine (1) and nornuciferine (3).Chromatography on neutral alumina gave 1 (25 mg) and 3(10 mg).The above experiment was repeated, with the modification that the A7-oxide S02 complex was refluxed not with acid, but with 5% aqueous sodium hydroxide. Preparative tic (2% MeOH in CHCls, A1203) gave I (38 mg), 3 (18 mg), and dehydronuciferine (12, 25 mg).

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It is demonstrated that the ionization potentials of primary, secondary, and tertiary aliphatic amines correlate very well with the inductive and polar substituent constants, the only seriously deviating value being that for ammonia, itself. The correlation equation is found to be EI = 9.62 + 13.8 ΣσI.

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Correlation of molecular ionization potentials, E,, with Taft's alkyl inductive substituent constants, cr,(,,, has now been extended to include the esters. It is found that three series of esters, the forrnates, acetates, and methyl alkanoates, fall on three separate straight lines in accord with the general equation (,,, where Eo is the intercept and a, the slope. The average standard error for the three lines is 0.024 eV with an average correlation coefficient of 0.992, showing that the alkyl substituent exerts an inductive influence on the electron density at the site suffering the electron loss: a lone pair on either the carbonyl or alkoxy oxygen atom. Evidence is deduced for the site of electron expulsion and a prediction is made concerning the site of vapor phase protonation of esters and carboxylic acids. E, values presently not available experimentally are predicted for several esters. [Traduit par le journal I Can. J. Chem., 51.3963 (1973) We demonstrate in this paper that the ionization potentials of various series of carboxylate esters are linearly correlated with Taft's alkyl inductive substituent constants, o, (1).A huge body of data relating to many physical properties of organic molecules has been correlated with different sets of substituent constants, such as o,, o* (2), and Hammett's original (3) 0 and its offshoots. The ionization energies of the alcohols (4a), ethers (4b), thiols (4c), thioethers (4d), alkyl halides (4e), ketones (4f), carboxylic acids (4g), copper acetylacetonates (4h), amines (44, nitriles (5), nitroalkanes (5), n-alkanes (6), alkenes (7), alkynes (8), and disulfides (9) have recently been shown to be linear functions of both the inductive and polar substituent constants.Assuming the validity of Koopmans' theorem (10) which identifies the first adiabatic ionization energy with the energy of the highest occupied molecular orbital, the electron must be lost from a non-bonding lone pair on one of the oxygens of the carboxyl group (I I). This may be represented by the following equationEvidence will be given later in this paper pertaining to wlzich oxygen is the probable site of electron loss. It is quite apparent that electronreleasing alkyl groups should increase the electron density at the relatively electronegative carboxyl group and consequently facilitate ionization of the molecule. A similar effect should manifest itself in a greater basicity, the greater the electron density at the carboxyl group, as in the case of alcohols (12).The ol(,, values and the experimentally determined (1 3) photoionization potentials of three series of esters, HCOOR, MeCOOR, and RCOOMe are given in Table 1