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The halo acetates obtained from ribo nucleosides and 2-acetoxyisobutyryl halides have been shown to readily react with chromous acetate and ethylenediamine in ethanol at -78°to produce 2',3'-dideoxy-d-D-gZycero-pent-2'-enofuranosyl nucleosides. In this way 2',3'-unsaturated analogs of adenosine, formycin, inosine, 5',A^-dibenzoylguanosine, and uridine have been prepared. Simple 3'-deoxy nucleosides and 3'-deoxy-/3-D-gZycero-pent-3enofuranosyl nucleosides are sometimes obtained as by-products. An alternative synthesis of the 3',4'-unsaturated analog of adenosine has been achieved via a base-catalyzed elimination reaction. Some interesting features of the nmr and ORD spectra of 2',3'-unsaturated nucleosides are reported. An alternative synthesis of 9-(2-0-acetyl-3-deoxy-3-halo-/3-D-xylofuranosyl)adenines has been developed uia the reaction of 2',3'-0-ethoxyethylideneadenosine with boron trifluoride etherate in the presence of anhydrous halide salts.

ing temperature is n-hexyl alcohol, ra-hexyl ether, n-Bu3P, internal standard, and n-BusPO.1,2-Dioxane was prepared by the method of Criegee8 in 18% yield. The product had bp 49°(67 mm) [lit.9 bp 61-62°(110 mm)]; n20D 1.4261 (lit.7 1.4262). Ir, mass, and nmr spectra confirm the structure.1,4-Butanediol was trapped from the glc effluent of a reduced sample of 1,2-dioxane for comparison with an authentic sample.The best column for quantitative glc analysis of the components of a reduced sample of 1,2-dioxane was a 10 ft X 0.25 in. Carbowax 20M (16.7%) on AW Chromosorb P (60-80 mesh); 2-dodecanone was used as internal standard.Di-ierf-butyl peroxide was obtained from Lucidol and was 99.9% pure by glc.Ascaridole was obtained from K & K. The reduction product, p-menthene-1,4-diol, was prepared by hydride reduction. Ascaridole (1.7 g, 1.01 X 10~1 2 mol) in 30 ml of benzene was refluxed with NaAlH2(OCH2CH2OCH3)2 (2.86 X 10~2 mol) for 2 hr. On cooling, 50 ml of water was added, benzene was removed on a Rotavapor, and the aqueous phase was

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The 2-aminothiazol-4-yl-2-alkoxyiminoacetamido substituent-containing i3-lactam antibiotics (cephalosporins and monobactams) develop a stable, concentration-dependent purple or cherry-red color after reaction with sodium nitrite in acidic condition. The color-formation is highly specific; it requires certain defined structural features such as the simultaneous presence of the intact aminothiazole-ring and an alkoxyimino substituent in the syn configuration. Other substituents on the (3-lactam nucleus have effect only on the intensity of the color. This simple and fast colorimetric procedure was found to be useful not only for the detection of this class of (3-lactam antibiotics but also for their quantitative spectrophotometric determination (2me .g 500 nm). A linear relationship exists between the intensity of the color plotted on a logarithmic scale and the concentration (12.5-200 i g/ml) of the compounds on an arithmetic scale. The j3-lactams studied in this class with definitely positive purple-red color reaction are; cefotaxime, ceftizoxime, ceftazidime, ceftriaxone, cefmenoxime, cefodizime, ceftiolene, cefpirome, aztreonam, HR 109, FK 027 (cefixime), FR 19346, SK&F 88070, FR 13300, carumonam, YM 13115, BMY 28142, DN 9550, deacetylcefotaxime, deacetoxycefotaxime and deacetylcefotaxime lactone.Most of the new semisynthetic cephalosporins and the monobactam, aztreonam, belong to the class of compounds containing the 2-aminothiazoleacetamido group. Those which contain a 2-alkoxyimino substituent at the syn-configuration are of considerable therapeutic interest. They have broad antibacterial spectra, high levels of activity especially against Gram-negative bacteria and excellent (3-lactamase stability1). These antibiotics are currently assayed using biological methods.A simple colorimetric procedure was developed based on the structural similarity between these 43-lactams and the sulfonamides, procaine (novocain) and other p-aminobenzoic acid derivatives. It was reasoned that the aromatic amino group of the aminothiazole ring of the (3-lactams similar to that of the sulfanilamides and procaine should form a colored compound after diazotization with sodium nitrite followed by coupling with N-1-naphthylethylenediamine.However, when this reaction was carried out as described in the literature2-7), there was apparently no coupling reaction, as evidenced by the lack of characteristic color. A concentration-dependent purple color did develop, however, when the sodium nitrite-treated solutions of the alkoxyiminoaminothiazolyl cephalosporins were acidified. This observation served as a basis for the development of the colorimetric detection and the spectrophotometric determination of these ,8-lactam antibiotics, as described herewith. Part of these data were previously reported8). Materials and Methods Antibiotics and Other CompoundsThe aminothiazolyl 19-lactam antibiotics and the aminothiazole-containing non-antibiotic control