GB1492573A - 9-substituted-pyrido(1,2-a)pyrimidines - Google Patents

Abstract

1492573 Derivatives of 4H-pyrido[1,2-a]- pyrinidin-4-one CHINOIN GYOGYSZER ES VEGYESZETI TERMEKEK GYARA RT 22 Nov 1974 [24 Nov 1973] 50747/74 Heading C2C The invention comprises compounds of formula and their salts, wherein X is O or S; R 1 is H, optionally substituted alkyl, alkenyl, optionally substituted aryl, optionally substituted aralkyl or acyl, R 2 is H, OH, halogen, optionally substituted alkyl, optionally substituted aryl, optionally substituted aralkyl, optionally substituted amino, alkoxy, optionally substituted hydrazino, CO 2 H or a derivative thereof; R 3 is H, halogen, optionally substituted alkyl, optionally substituted aralkyl, optionally substituted aryl, nitro, optionally substituted amino, CO 2 H or a derivative thereof; and R 4 is attached to the A ring and is H, halogen, alkyl or CF 3 ; provided that (1) X cannot be O if either (a) R 3 is H and R 2 is Me, or (b) R 2 is H and R 3 is CO 2 Et; and (2) if R 2 is H, alkyl, aryl or aralkyl and R 1 is other than acyl, R 3 is not H, CO 2 H or alkoxycarbonyl. These compounds as well as their analogues within the scope of the provisos, are prepared by reacting together a 2-amino-3- oxy (or -thio) pyridine and (in examples) a compound corresponding with the formula RO-CR 2 =CR 3 -CO 2 Et (R being H or Et), with or without isolation of the intermediates initially formed, prior to cyclization in presence of an acidic condensation agent. Exemplified isolated intermediates have the formula or possibly where R<SP>0</SP> is Me, Ph or CO 2 Et, and Z is 3-hydroxy- 2-pyridyl. Therapeutic compositions having antibacterial and C.N.S. (e.g. tranquillizing and/or analgesic) activity, and which are preferably administered orally, comprise compounds, of the above formula, provided that (i) X is S when R 3 is H and R 2 is Me, (ii) neither R 2 nor R 3 is halocarbonyl, and (iii) R 1 is H or acyl when R 2 is H, alkyl, aryl or aralkyl and R 3 is H, CO 2 H or alkoxycarbonyl.