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Ethyl 4-oxoalkanoates 1 react at ambient temperature in dry methanol in the presence of molecular sieve 3 A in almost quantitative yield with 3-aminopropanol and 2-aminoethanol to form the bicyclic lactams rac-2 and rac-3, respectively. Owing to their carbon skeleton, ethyl 4-oxoalkanoates 1 are interesting starting materials for the synthesis of 1,4-diketones and, thus, of furans2x3), pyrroles4), and 2,3-dialkylcyclopent-2-en-1-ones'). Formally, the conversion of 1 into 1,4-diketones requires the nucleophilic substitution of the alkoxy group of 1 by an alkyl group. This can be achieved by the reaction with suitably metalated alkanes provided the +ox0 group is protected and the ester group is modified in such a way that the metalated alkane adds to the ester carbonyl group only once. Several examples are known for this strategy6). The bicyclic lactams 2 and 3, which have not been investigated so far, should be available by condensation of ethyl 4-oxoalkanoates with 3-aminopropanol and 2-aminoethanol, respectively. They were expected to correspond to the above-mentioned requirements.Indeed, by standing at ambient temperature for four days, the reaction of ethyl 4-oxoalkanoates l a -e with 3-aminopropanol in dry methanol affords the expected bicyclic lactams ruc-2a-e in yields of 82-97% as colorless liquids. The structure of these compounds has been confirmed by their I3C-NMR spectra exhibiting singlets for the carbonyl group (C-9) at 6 = 173.2-173.9 and for C-6 at 6 = 89.8-92.5. The triplets at 6 = 29.0-29.2 and 30.5-33.6 can be attributed to the pyrrolidinone ring (C-7, C-8) and the triplets at 6 = 60.7 -61.0, 24.7 -24.9, and 35.2 -35.4 to the six-membered ring (C-4, C-3, and C-2, respectively). A corresponding number of additional signals is caused by the carbon atoms of the different alkyl groups.The analogous reaction of the ethyl 4-oxoalkanoates l a -e with 2-aminoethanol in dry methanol at room tem- perature gives rise to the formation of the bicyclic lactams rac3a -e in nearly quantitative yields. The structure of these compounds has been confirmed by their IR, mass, and 13C-NMR spectra. The latter showed singlets for the carbony1 group (C-8) at 6 = 178.6-179.0 and for C-5 at

The title compound 9-vinyladenine crystallizes in the monoclinic space group C2/c with 16molecules in the unit cell and the lattice parameters a = 13.682, b = 10.260, c = = 21.674 A, /? = 97.72". The crystal structure has been determined by direct methods and refined by full matrix least squares calculations up to the discrepancy factor R = 0.045.The two symmetry independent molecules differ in the orientation of the vinyl group relative to the adenine frame.Die Titelverbindung 9-Vinyladenin kristallisiert, in der monoklinen Raumgruppe C 2 / c mit 16 Molekulen in der Elementarzelle und den Gitterkonstanten a = 13,682, b = 10,250, e = 21,674 A, /I = 97,72". Die Kristallstruktur wurde mit direkten Methoden bestimmt und mit der Methode der kleinsten Quadrate bis zu einem R-Wert von 0,045 verfeinert.Die zwei symmetrieunabhangigen Molekule unterscheiden sich in der Orientierung der Vinylgruppe relativ zum Adeninkfirper.

The title compound 6r-methyl-3.20-dioxo-5fl-pregnan-l7~(-yl acetate crystallizes in the monoclinic space group: 2, with two molecules in the unit cell and the lattice parameters a = 10.889. b = 1 1.056, c = 9.8029A, fl = 101.51" The crystal structure is isostructural with medroxyprogesterone acetate and refined by full matrix least squares calculations up to the discrepancy factor R = 0.05 1.Die Titelverbindung 6c(-Methyi-3,20-dioxo-5fl-pregnan-l7a-yl-acetat kristallisiert in der rnonoklinen Raumgruppe P 2, mit zwei Molekiilen in der Elementarzelle und den Gitterkonstanten a = 10,889, b = 11,056 und c = 9.8029 A. = 101,51" Die Kristallstruktur ist isostrukturell rnit Medroxyprogesteronacetat und wurde mit der Methode der kleinsten Quadrate bis zu einem R-Wert von 0,051 verfeinert.