This invention relates to a new and improved process for the preparation of 6,7-dichloro-1,5-dihydroimidazo[2,1-b]-quinazolin-2[3H]-one of formula ##STR1## (anagrelide), a valuable blood platelet antiaggregative compound. According to the process of the invention the compound of formula (I) is prepared by subjecting a new 2-cyanoiminoquinazoline derivative of the general formula ##STR2## wherein R stands for cyano or a group of the formula COOR.sup.1, in the latter R.sup.1 representing lower alkyl optionally carrying a phenyl substituent, to thermal cyclization in an acidic medium. The invention also relates to new 2-cyanoiminoquinazo-lines of the general formula (III) used for the production of anagrelide and to the preparation of the said compounds. The invention provides an advantageous process for the preparation of anagrelide which is devoid of the drawbacks of the hitherto known processes and renders possible the production of the compound of the formula (I) on industrial scale, too.
Anti-ulcer agents of the formula ##STR1## wherein R.sup.1 is a straight or branched chain alkynyl group containing from 3 to 9 carbon atoms, inclusive, and non-toxic pharmaceutically acceptable acid addition salts thereof, are prepared by reacting a compound of the formula ##STR2## with a compound of the formula ##STR3## wherein R.sup.1 is as defined above and R.sup.5 is (lower)alkyl, phenylalkyl or phenyl containing 1 or 2 substituents independently selected from nitro, chloro and bromo. The intermediates of Formula IV may be prepared by reacting the desired alkynylamine with a compound of the formula (R.sup.5 S).sub.2 C.dbd.NCN V in which R.sup.5 is as described above.
Fromm; Kapeller-Adler, Justus Liebigs Annalen der Chemie, 1928, vol. 467, p. 254
作者:Fromm、Kapeller-Adler
DOI:——
日期:——
Process for and 2-(cyanoimino)-quinazoline derivatives useful as intermediates in the preparation of 6,7-di-(chloro)-1,5-di(hydro)-imidazo-[2,1-b]quinazolin-2[3H]-one and process for preparing the 2-(cyanoimino)-quinazoline derivatives
申请人:EGIS GYOGYSZERGYAR
公开号:EP0514917B1
公开(公告)日:1996-12-27
Ringschlußreaktionen mit 5-Aminotetrazol: Ein neuer Weg zur Synthese von Azido-<i>s</i>-triazinen