Various novel pyrano [2,3-d]pyrimidines 5 and furopyrano [2,3-d]pyrimidines 7 were synthesized in 80-99% yields via a multicomponent domino Knoevenagel/hetero-Diels-Alder reaction of 1,3-dimethyl barbituric acid with an aromatic aldehyde and ethyl vinyl ether/2,3-dihydrofuran in presence of 1 mol% of indium(III) chloride. The reaction also proceeds in aqueous media without using any catalyst, b...

Knoevenagel condensation between barbituric acid and aldehyde was investigated in the presence of sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) and resulted in the formation of arylidene and bis-arylidene barbiturates. Excellent yields and short reaction times are related to the high efficiency of SBA-Pr-SO3H that the reactions take place easily in its nano-pores. SBA-Pr-SO3H as ...

Soluble and membrane associated proline dehydrogenase differ in catalytic properties. The soluble enzyme transfers electrons from L-proline to exogenous electron acceptors. It has a high Km for L-proline (105 mM) and is insensitive to the respiratory chain inhibitors 5-ethyl-5-isopentyl-barbituric acid and cyanide. The membrane-associated enzyme transfers electrons from L-proline to O2 via the ...