Novel compounds of the general formula (XIX) ##STR1## where R.sup.9 is selected from lower alkyl, phenyl, phenyl substituted by one or more hydroxy or lower alkoxy, or pyridyl, are disclosed. A method of making the compounds of Formula (XIX) is disclosed, which comprises heating in aqueous acid a compound of formula (XX) ##STR2## wherein R.sup.10 is selected from lower alkyl, phenyl, phenyl substituted by one or more hyroxy or lower alkoxy or pyridyl and R.sup.11 is selected from lower alkyl, phenyl, substituted by one or more hydroxy or lower alkoxy, pyridyl or --CO.sub.2 R where R is lower alkyl.
本发明揭示了一般式(XIX)的新化合物:##STR1## 其中R.sup.9从低烷基、苯基、被一个或多个羟基或低烷氧基取代的苯基或
吡啶基中选择。本发明还揭示了一种制备式(XIX)化合物的方法,其中包括在
水酸中加热式(XX)化合物:##STR2## 其中R.sup.10从低烷基、苯基、被一个或多个羟基或低烷氧基取代的苯基或
吡啶基中选择,R.sup.11从低烷基、苯基、被一个或多个羟基或低烷氧基取代的苯基、
吡啶基或--CO.sub.2 R(其中R是低烷基)中选择。