Novel palladium(II) complexes (4-6) have been synthesized from the reaction of (E)-3{[(diethoxythiophosphoryl)-methylhydrazone]-methylene}-4-hydroxy-2H-1-benzopyran-2-one (1), E)-3-{[(dimethoxythiophosphoryl)-methylhydrazine]-methylidene}-3,4-dihydro-2H-1- benzopyran-2,4-dione (2) and (E)-3-{[(diethoxythiophosphoryl)-hydrazone]-methylene}- 4H-1-benzopyran-4-one (3), respectively, with PdCl2(PhC...

A series of 6,8-diiodocoumarin-3-N-carboxamides (4-11) were prepared. Treatment of ethyl 6,8-diiodocoumarin-3-carboxylate (1) with ethyl cyanoacetate/NH(4)OAc gave ethyl 2-(3-carbamoyl-6,8-diiodocoumarin-4-yl)-2-cyanoacetate (12) and 2-amino-4-hydroxy-7,9-diiodocoumarino[3,4-c]pyridine-1-carbonitrile (13), and treatment with acetone in the presence of NH(4)OAc or methylamine gave the ethyl 4-ox...

The bile acid precursor 7 alpha-hydroxy-4-cholesten-3-one was found to be enzymatically dehydroxylated at a slow rate by liver tissues from the rat, human, and guinea pig. The rat liver enzyme is localized in the microsomal fraction, has a pH optimum of about 8.5, an apparent Km of 0.03-0.04 mM, and a Vmax of 10-15 nmoles.mg protein-1.hr-1. The product from 7 alpha-hydroxy-4-cholesten-3-one was...

Reaction of 4-hydroxy-7-methoxy-2(lH)-quinolone (1) with iodosobenzenes, prepared in situ from the dichloroiodo compounds 2a,b, afforded the iodoniumylides 3a,b in good yields. Their thermal rearrangement produced the 3-iodo-4-aryloxy-quinolones 4a,b. Reductive -deiodinatton of 4a,b gave the corresponding arylethers 5a,b. By photocyclization 4a as well as 5a yielded the benzofuro-quinolone 6a (...

In the title compound, C(5)H(8)N(3) (+)·C(7)H(5)O(3) (-), the pyridine N atom is protonated. In the 4-hydroxy-benzoate anion, the carboxyl-ate group is twisted slightly out of the benzene ring plane by an angle of 3.77 (5)°. The protonated N atom and one of the two amino groups are hydrogen-bonded to the 4-hydroxy-benzoate anion through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) rin...

Hydroxy-L-proline was first isolated by Fischer in 1902 from a hydrolysate of gelatin (l).l The synthesis and determination of the structure were reported by Leuchs and coworkers (5--g), and, in 1919, the separation of the two racemic stereoisomers and the resolution of each racemate through mixtures of quinine with the corresponding N-phenylisocyanate derivatives were accomplished (5). In the ...

(E)-1-Hydroxy-2-methylbut-2-enyl 4-diphosphate reductase (IspH) is a [Fe4S4] cluster-containing enzyme involved in isoprenoid biosynthesis in many bacteria as well as in malaria parasites and is an important drug target. Several inhibitors including amino and thiol substrate analogues, as well as acetylene and pyridine diphosphates, have been reported. Here, we investigate the mode of binding o...