PROCESS FOR THE PREPARATION OF 3,7-DIALKYLXANTHINES

PROCESS FOR THE PREPARATION OF 3,7-DIALKYLXANTHINES

PCT No. PCT/EP90/01478 Sec. 371 Date Mar. 2, 1992 Sec. 102(e) Date Mar. 2, 1992 PCT Filed Sep. 4, 1990 PCT Pub. No. WO91/03477 PCT Pub. Date Mar. 21, 1991.The invention is directed to a process for preparing 3,7-dialkylxanthines of the formula I (I) (R1 and R2 denote C1-C4-alkyl) by the reaction of...

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Bibliographische Detailangaben
Hauptverfasser: JANITSCHKE, LOTHAR, KARL, ULRICH, LENZ, HANS-HEINRICH, BUGGLIN, MARIUS, GROPP, HERBERT
Format: Patent
Sprache:eng
Schlagworte:
CHEMISTRY
HETEROCYCLIC COMPOUNDS
METALLURGY
ORGANIC CHEMISTRY
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Zusammenfassung:PCT No. PCT/EP90/01478 Sec. 371 Date Mar. 2, 1992 Sec. 102(e) Date Mar. 2, 1992 PCT Filed Sep. 4, 1990 PCT Pub. No. WO91/03477 PCT Pub. Date Mar. 21, 1991.The invention is directed to a process for preparing 3,7-dialkylxanthines of the formula I (I) (R1 and R2 denote C1-C4-alkyl) by the reaction of 4-amino-imidazolecarboxamide-(5) of the formula II (II) with an alkali cyanate in aqueous solution at a pH of from 3 to 5 followed by cyclization of the resulting urea derivative at a pH of from 8 to 14.