A ceramic electrochemical reactor (CEM) devoted to electrosyntheses was developed. The CEM was constituted by the assembly of five structured ceramic layers. On one layer, platinum interdigitated band electrodes with a submillimetre interelectrode gap were screen-printed. The microreactor chamber was constituted by seven channels and its volume was less than 100 microL. After a sintering step at 850 degree C for 1 h, the CEM appeared as a solid and compact unit. The CEM was directly connected to the six port valve of a mass spectrometer allowing an on-line sampling and analysis of the reaction mixture. The methoxylation of the methyl-2-furoate was carried out and the effect of the residence time in the CEM was investigated thanks to mass spectrometry analyses.

Surnmmy. N-Ethoxycarbonyl4pyddone is reduced to N-etho~carbnyl4-01~ 2.3,4tetrahydmpyridine by sodium borohydride in t-butyl alcohol containing cthyl chloroformate. Saponification of the product leads to 4-Oxo-1.2,3,4-tetrahydropyridine.1, Introduction. -Some N-alkylated 4-0~0-1,2,3,4-tetrahydropyridines have been most successfully synthesized by reduction of the corresponding N-alkyl pyridones with hydroaluminates. A first example was given by WiW@&&! [l] who reduced N-alkyl-4-0~0-1,2,3,4-tetrahydmpyridine. Other N-alky~-4-0~0-1,2,3,4- N-[Z-(indol-3-yl)-ethyl]-4-pyridone with lithium aluminium hydride to the corresponding tetrahydropyridines wexe prepared by Tamwu d d. [ZJ treating N-alkyl pyridonc-with lithium triethoxy aluminium hydride. Such compounds have also been obtained by other procedures: An example by Hebky et aZ. [3] showed that they are accessible by catalytic hydrogenation of pyridones; Stiitz et al.[4] found an opposite mode of access: dehydrogenation of an N-alkyl piperidone occurred following a peracid and acetic anhydridelbase treatment by means of a modified type of the Polonovsky reaction. A total synthetic route to some 2,6-disubstituted 4-oxo-l,2,3,4tetrahydropyridines is reported by Szsgiyamas group 1' 51 condensing Schiff-bases with dialkali salts of Bdiketones.

SummaryDehydration of abiet-8-ene-7/i, 13P-diol (ibozol, 1) leads to abieta-7,9 (1 1)-dien-13B-01 (2) which aromatizes slowly to the known abieta-8,11,13-triene (3). Photosensitized oxygenation of the heteroannular diene 2 yields a mixture from which three compounds were identified: abiet-7-ene-9n, 11 a , 13P-trio1 (4), abieta-8,11,13-trien-7-one (5), and abieta-8,11, 13-trien-7 u-01 (6).Introduction. -There is considerable interest in the potent anti-leukemic activity and cytotoxicity of certain naturally occurring oxygenated diterpenes [ 1-31 and various synthetic approaches have been recently described [4]. In view of our interest in potential anti-tumoral agents, we report on the photosensitized oxygenation of the previously unknown heteroannular diterpene, abieta-7,9 (1 I)-dien-13 /3-01 (2), prepared from ibozol (1, abiet-8-ene-7b, 13P-diol) a diterpene isolated from the Labiatae Zboza riparia NE BROWN [5]. The photosensitized oxygenation of simpler substrates is well known [6] but few examples are documented in the diterpenoid series [7].

SummaryMethylation of ethyl 2,4-dioxopentanoate with diazomethane gives a mixture of two enol ethers, the 2-methoxy and the 4-methoxy isomer, with a product ratio which depends upon reaction temperature. Both enol ethers, initially (2)-configurated, isomerize to the corresponding (E)-conformers, the 4-methoxy compound with particular ease.

Durch Dehydratisierung entsteht aus dem Diol (I) ein trennbares Gemisch aus der Titelverbindung (II) und dem Trien (III).