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Vilsmeier and Mannich reactions on (4S)-N2-substituted 4-methyl-2,4-dihydro-1H-pyrazino(2,1-b)quinazoline-3,6-diones


, : Vilsmeier and Mannich reactions on (4S)-N2-substituted 4-methyl-2,4-dihydro-1H-pyrazino(2,1-b)quinazoline-3,6-diones. Tetrahedron 54(12): 2777-2784

The enamine character of the CH2-C(11a)=N(11) fragment in the title compounds was studied. Compounds 1 gave 1-dimethylaminomethylene products 5 after Vilsmeier reaction. The 1-formyl derivatives, obtained by alkaline hydrolysis of 5, were isolated as enol tautomers and were very unstable in acid media. On the other hand, acid-promoted elimination of dimethylamine from the Mannich reaction products 7 gave 1-methylene derivatives 8, which showed an interesting reactivity.

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Jennische, M.; Sedin, G., 2001: Spontaneous speech at 6 1/2 years of age in children who required neonatal intensive care in 1986-1989. Spontaneous speech at 6 1/2 y of age was studied in a follow-up of 230 children born in 1986-89 who had required neonatal intensive care (NIC) and 71 fullterm neonatally healthy control children. Eight aspects of spontaneous speech were examined:...

Inoue, S.; Tilney, LG., 1982: Acrosomal reaction of Thyone sperm 1 Changes in the sperm head visualised by high resolution video microscopy. Structural changes inside the head of Thyone sperm undergoing the acrosomal reaction were followed with a high-resolution, differential interference contrast (DIC) video microscope. The beating sperm, adhering by their midpiece to the cover slip o...

Klein, M.S., 1989: Adapting IAIMS to a hospital library level. The Children's Hospital of Michigan Medical Library has adapted several of the Integrated Academic Information Management Systems (IAIMS) concepts and implemented them at a hospital library level. These have included features of network devel...

Judet, O.; Rouveix, E.; Verderi, D.; Bismuth, V., 1989: A classical but unknown cause of peritoneal effusion disclosed by echography. Typhoid fever. Two cases of peritoneal effusion discovered by sonography in patients with typhoid fever are reported. These peritoneal effusions have no pejorative value; only clinical findings can differentiate these simple effusions from a perforative thyphoid...

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Montefameglio, L.; Pavia, G.; Rosa, DA., 1979: Associazioni a molluschi del tabianiano del basso Monferrato Alba, Italia NW. Bollettino della Societa Paleontologica Italiana, 182: 173-199

Negoro, T.; Tobe, T., 2005: Immunological tests: Decay-accelerating factor. Nihon Rinsho. Japanese Journal of Clinical Medicine 63 Suppl 7: 98-100

Kikuchi, H., 1981: Ecological studies on the planting density of mulberry 3. seasonal variation in dry weight of roots stumps shoots and leaves. The effect of planting density on the subsequent growth pattern of various organs was examined by varying planting densities (500, 1000, 3000, 6000, 10,000 and 15,000 trees/10 ares) using the trees of cultivar Kenmochi, which had been grown from t...

Sakamoto K.; Yoshida T., 1988: In situ measurement of soil respiration rate by a dynamic method. In this paper, various problems relating to the in situ measurement of soil respiration rate by a dynamic method in which CO2 was directly measured by an infrared gas analyzer were discussed. The rate of soil respiration increased with increasing...