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The reactions of thiapyrylium salts 3a–c with hydrazine and methylhydrazine yield the 3,5,7-triphenyl-1,2(4H)-diazepines 4a–c and 1-methyl-3,5,7-triphenyl-1,2(1H)-diazepines 5a–c in good to excellent yields. Although numerous 1-acyl-1,2(1H)-diazepines are now known, compounds 5a–c represent the first examples of 1-alkyl-1,2(1H)-diazepine derivatives. With a slight variation in work up conditions, the reaction of thiapyrylium salts 3a and 3c with methylhydrazine leads to the formation of the pyrazoline derivatives 6a and 6c, respectively; on the other hand, only pyrazolines 9a and 9b can be obtained from the corresponding reaction with phenylhydrazine. Pyrolysis of the pyrazolines 6a, 6c, 9a, and 9b provides the pyrazoles 7a, 7c, 10a, and 10b, respectively. The mechanism of some of these transformations is briefly discussed.

The reaction of pyrylium salts 1a–e with methylhydrazine gives pyrazolines (2), pyrazoles (3), pyridines (4), 1,2-diazepine (5), and N-methylaminopyridinium salts (6). Product composition has been studied as a function of pyrylium salt counter anion, concentration of methylhydrazine, and conditions of the reaction (Table 1). Pyridines (4) and 1,2-diazepines (5) are minor components, the major products being the pyrazolines (2) and pyrazoles (3). The reactions of more unusual pyrylium salts (1f–i, 8a, 9a, 9c, and 11a) with hydrazine have been shown to provide 1,2(4H)-diazepines (10, 12–15) and N-aminopyridinium salts (8b, 9b) (Table 2), the nature of the product apparently depending on the absence or presence of 2-methyl substitution respectively in the starting pyrylium salts.

Hydroformylation of 5,6-anhydro-1,2- O -isopropylidene-α- D -glucofuranose ( 1 ) with carbon monoxide and hydrogen in the presence of dicobalt octacarbonyl for 1.5 h at 105° gave 6-deoxy-1,2- O -isopropylidene-α- D -gluco-heptodialdo-1,4-furanose- 7,3-pyranose ( 5 ) and 6-deoxy-1,2- O -isopropylidene-α- D - xylo -hexofuranos-5-ulose ( 3 ) in 78 and 7% yields, respectively. The dialdose 5 was acetylated to afford the diacetate 6 , which was fused with 5,6-dimethylbenzimidazole in the presence of monochloroacetic acid to afford an anomeric mixture of nucleosides 7a and 7b .

The reaction of pyrylium salts 1a–e with methylhydrazine gives pyrazolines (2), pyrazoles (3), pyridines (4), 1,2-diazepine (5), and N-methylaminopyridinium salts (6). Product composition has been ...

Daily fluctuations in fecal pollution indicators in the Fraser River estuary were examined by sampling through 24 h at four sites; water levels, currents, and salinities were observed simultaneously. Fecal coliforms were measured on shipboard using the membrane filter technique, and coprostanol and cholesterol were extracted using hexane and analyzed by gas chromatography. Maximum concentrations of fecal sterols and coliforms occurred after high tide at the station upstream of major sewage outfalls and on the ebb or at low tide at the stations downstream of major sewage outfalls. Fecal coliform counts were highly correlated with coprostanol and cholesterol levels at sites near sewage treatment plants. Coprostanol was highly correlated with cholesterol except where concentrations approached detection limits. In receiving waters, fecal coliform counts but not sterol concentrations were reduced by chlorination of sewage treatment plant effluents during the summer months. We concluded that, dependent on the objectives of a future monitoring program, samples should be collected either randomly in time such that the seasonal or annual mean includes tidal variability or systematically during the ebb tide to assess contributions to bathing beaches and shellfish harvesting areas. Fecal sterols deserve consideration as potential indicators of fecal contamination from chlorinated sewage effluents.

The reactions of thiapyrylium salts 3a–c with hydrazine and methylhydrazine yield the 3,5,7-triphenyl-1,2(4H)-diazepines 4a–c and 1-methyl-3,5,7-triphenyl-1,2(1H)-diazepines 5a–c in good to excelle...

Photolysis of the methyldiazepine (5a) led directly to the pyrazole (7) whereas the ethoxycarbonyl- and acetyl-diazepines (5b) and (5c) gave cycloadducts (6b) and (6c); thermolysis of the diazepines (5) or the diaza[3,2,0]bicycloheptadienes (6) produced mainly ylides (8) and small amounts of 2,4,6-triphenylpyridine (9), except for (5a) which yielded (9) only.

The reaction of (1; R = Ph or Me) with methyl-hydrazine leads to a variety of products, (2e), (3d), (3e), (5), (6a), and (7), depending on the selected pyrylium salt and reaction conditions.

Photolysis of the pyridinium ylides (4) and (5) produces, besides high yields of aniline and (8) and (9) respectively, the additional products (10)[from (4) in benzene] and (12)[from (5) in diethylamine] which suggest a phenyl nitrene intermediate in these reactions.