The 10 lysergic and iso-lysergic acid amides described are N,N-dimethyl-, N,N-diethyl-, N-methyl-N-propyl, N-ethyl-N-propyl, and N,N-dipropyl-. Their ultraviolet spectra are insufficiently different for distinction. Mass spectra do not readily differentiate between isomers. Proton magnetic resonance spectra are distinct and provide a positive structural identification of the amide. Their infrared spectra are similar, but suitable for distinguishing these compounds from LSD. Various reference spectra are provided. Thin layer and gas-liquid chromatographic systems suitable for distinguishing these compounds from LSD are described.

The 220 MHz p.m.r. spectra of the dimethylamides of D-lysergic acid (3) and D-bo-lysergic acid (4) are reported. Extensive use of double resonance experiments and the presence of four long-range coupling constants provide an unambiguous assignment for the conformation of 3 in CDCI,. Its D ring is shown to exist in a half-chair form in which the 8-8 amide function is pseudo-equatorial. Its epimer essentially exists in the other half-chair form with a pseudo-equatorial 8-a amide function. Data from the p.m.r. spectra of a series of N,N-dialkylamides of these acids are also presented.The spectrum of protonated 3 at 23°C shows two forms of the 6-NCH, and 8-CON(CH,)' groups but only one for the epimer 4.Les spectres de r.m.n. a 220 MHz des dimethylamides de I'acide D-lysergique (3) et de I'acide D-;so-lysergique (4) sont rapportes. L'usage extensif de la double resonance et la presence de quatre constantes de couplage a longue distance ont permis d'attribuer sans ambiguiti. la conformation de 3 dans le CDCI,. On a montre que le cycle D de ce dernier existe sous la forme demi-chaise dans laquelle la fonction amide-8P est pseudoequatoriale. Son epimtre existe essentiellement sous I'autre forme demi-chaise avec la fonction amide%a pseudo-equatoriale. Les donnees des spectres de r.m.n. d'une serie de N,N-dialkylamides de ces acides sont egalement presentes. Le spectre de3 sous forme protonee a 23 "C montre deux formes pour les groupes NCH,-6 et CON(CH,)'-8 alors que I'epimere 4 n'en donne qu'une.

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