4-Aminofuro[2,3-d]pyrimidine und deren Verwendung als Relaxantien fuer glatte Muskeln

摘要

1,205,117. 4 - Aminofuro [2,3-d] pyrimidines. CHAS. PFIZER & CO. Inc. 10 April, 1968 [5 Jan., 1968], No. 17392/68. Heading C2C. [Also in Division A5] Compounds of the formulµ (wherein X and Y are each H, C 1-4 alkyl, phenyl or naphthyl, or X and Y together are C 4-6 alkylene or benzo; R 3 is H or C 1-8 alkyl; R 1 and R 2 are each H, C 1-6 alkyl, C 2-6 alkenyl, phenyl, naphthyl or #-hydroxyethyl, or -NR 1 R 2 is morpholino, thiomorpholino or piperazino which may be N1-suhstituted by C 1-6 alkyl, C 2-6 alkenyl, alkoxycarbonyl, hydroxyalkyl, phenyl or naphthyl; R 4 , R 5 and R 6 are each H or C 16 alkyl; and n is 2,3,4 or 5) and acidaddition salts thereof, which are novel except when R 1 and R 2 are both H, are prepared, when R 1 and R 2 are each H, by condensing an α- hydroxy ketone with malononitrile in presence of a base and cyclizing the product with formamide, or by the process where NRR1 is ammonia the appropriate amine. This method is not used directly when X and Y together are benzo or tetrahydrobenzo, these compounds being prepared from the 4- (unsubstituted amino)-5,6,7,8-tetrahydrobenzofuro[2,3-d]pyrimidines (prepared, e.g. by condensing α-hydroxycyclohexanone with malonitrile and cyclizing with formamide) by nitrous acid oxidation to the 4-ones which are then, as above, reacted with POCl 3 and then the appropriate amine; dehydrogenation of the tetrahydro compounds, such as by heating with sulphur in decalin or palladium-carbon gives the 4-aminobenzofuro[2,3-d]pyrimidines.