A general reaction of glycosyl cyanides with liquid hydrogen sulfide in the presence of 4-dimethylaminopyridine to provide the corresponding glycosylthiocarboxamides is described. These glycosylthiocarboxamides were utilized as the precursors for the synthesis of 2-D-ribofuranosylthiazole-4-carboxamide and 2-beta-D-ribofuranosylthiazole-5-carboxamide (23). The structural modification of 2-beta-D-ribofuranosylthiazole-4-carboxamide (12) into 2-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)thiazole-4-carboxamide (15), 2-beta-D-ribofuranosylthiazole-4-thiocarboxamide (17), and 2-(5-deoxy-beta-D-ribofuranosyl)thiazole-4-carboxamide (19) is also described. These thiazole nucleosides were tested for in vitro activity against type 1 herpes virus, type 3 parainfluenza virus, and type 13 rhinovirus and an in vivo experiment was run against parainfluenza virus. They were also evaluated as potential inhibitors of purine nucleotide biosynthesis. It was shown that the compounds (12 and 15) which possessed the most significant antiviral activity were also active inhibitors (40-70%) of guanine nucleotide biosynthesis.

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A multiresidue method was developed and validated for simultaneous analysis of 5 families of mycotoxins in corn grain. Deoxynivalenol (DON); aflatoxins B1, B2, G1, G2; ochratoxin A; zearalenone; and fumonisins FB1 and FB2 are extracted from corn grain samples with watermethanol, and extracts are cleaned up using immunoaffinity and solid-phase extraction columns. The column high-performance liquid chromatographic method uses postcolumn photochemical derivatization for detection of aflatoxins and derivatization with o-phthalaldehyde for detection of fumonisins. Mean recoveries and relative standard deviation values () over studied fortification levels for the chosen matrixes were: DON 89.9, 8.7; aflatoxin B1 85, 9.4; aflatoxin B2 82.4, 9.7; aflatoxin G1 74.8, 13.5; aflatoxin G2 79.2, 10.0; fumonisin B1 96.2, 8.0; fumonisin B2 84.5, 6.4; zearalenone 91.7, 11.5; and ochratoxin A 87.4, 15.8. The method performance criteria, including specificity, accuracy, repeatability, operational range, and detection limits, were found to be within specifications set by the Feed Additives and Contaminants Group of the AOAC Agricultural Materials Community.

It has been previously shown by others7 that upon warming related diaza olefins noncharacterizable black materials are generated. Also upon treatment of either 6 or 7 with hydride ion (NaH, xylene, reflux) rapid deg-radation occurs to give a similar black, high-melting solid (H. C. R. Taylor, unpublished results). N-Alkylation reactions of 3-bromopyrazolo[4,3-d]pyrimidin-7-one and 3-bromo-7-chloro-and 3-bromo-7methoxypyrazolo[4,3-d]pyrimidineswere studied. Alkylations in aqueous base yielded predominately N -l alkyl products, as did trimethysilylation using hexamethyldisilazane. In contrast, alkylation with 2-chlorotetrahydropyran and sodiutn hydride in dimethylformamide or with dihydropyran and an acid catalyst in ethyl acetate yielded predominantly N-2 alkyl products. Formation of 3-lithio derivatives of N -l and N-2 alkylated 7-alkoxypyrazolo[4,3-d]pyrimidines from the corresponding 3-bromo compounds was accomplished by treatment with n-butyllithium at low temperatures. N-1 alkyl compounds yield complex mixtures of products, including those of N-dealkylation and rearrangement with rupture of the pyrazole ring. The N-2 alkylated compound, 3-lithio-7-methoxy-2-tetr~ihydropyran-2'-ylpyrazolo[4,3-d]pyrimidine, was stable and reacted with benzaldehyde in high yield.

The synthesis, characterization, and biochemical evaluation of 1-beta-D-ribofuranosylnaphtho[2,3-d]imidazole-4,9-dione (3), 2-beta-D-ribofuranosylnaphtho[2,3-d]pyrazole-4,9-dione (6), and 2-beta-D-ribofuranosylnaphthol[2,3-d]triazole-4,9-dione (9) are reported. These quinone nucleosides and the corresponding quinone heterocycles were tested as inhibitors of purine nucleotide biosynthesis in Ehrlich ascites cells. The nucleosides 3 and 9 and naphtho[2,3-d]imidazole-4,9-dione were effective inhibitors of hypoxanthine phosphoribosyltransferase.

3-Dimethylsulphonioindolide, an unusually THE stable, crystalline ylide (1) has been prepared and obbasic, crystalline ylide when dissolved in CDCI, or served t o possess unusual properties; in CDC1, or CD,OD CD,OD incorporates deuterium into the methyl groups. solutions a t or near room temperature i t incorporates

Amethod using ion-exchange liquid chromatographic (LC) separation, post-column derivatization, and fluorescence detection to quantify neomycin B and neomycin C in animal feeds has been developed and validated. Improved methodology is required to achieve positive identification of antibiotics present and to more accurately determine the amount of antibiotics in feeds. The method sample range covers additive levels found in type A, B, and C medicated feed products (500.005 wt/wt neomycin base). The linear range for the method covers 50150 of expected sample concentrations. Average recovery from type A and B feeds, n = 9, was 100.4 neomycin with RSD = 2.28. Average recovery from type C feeds and milk replacers, n = 9, was 97.5 neomycin with RSD = 4.36. There were no interferences from soybean meal and milk replacer matrix components, oxytetracycline, or other aminoglycosides, with the exception of one gentamicin isomer, which co-elutes with neomycin B. However, neomycin and gentamicin are not a legal feed combination, and the presence of gentamicin can easily be discerned by the appearance of the 3 gentamicin homologs that do not interfere. Comparison of the proposed LC method to the microbiological method shows that the LC method provides comparable recoveries of neomycin from feed products throughout the range of concentrations found commercially.