Hg lamp

Using the luminol photochemiluminescence it is possible to determine not only the nitrates (as reported by us earlier), but also the nitrites. The urotropin is added to the water sample, and the solution obtained is illuminated by the Hg lamp. The chemiluminescence is measured after the addition of basic luminol solution to the illuminated solution. The detection limit is 2-10 M. The nitrates contained in the drinking water do not interfere at tenfold excess. 

Fig. 14 Radiation characteristics of a high pressure Hg lamp (Osram HBO 100 continuous line) and of a xenon lamp (PEK 75 broken line) [4]. The intensity /is represented logarithmically in relative units.

Table 2. Summary of the most important technical data on the most frequently employed Hg lamps [47],...

A solution of dimethyl 3-acetyl-3-azatetracyclo[3.2.0.02-7.04 6]heptane-l,5-dicarboxylate (2, R1 = Ac R = H), formed by the photolysis (14 h 125-W Hg lamp under N2) of dimethyl 7-acetyl-7-azabicyclo-[2.2.1]hepta-2,5-diene-2,3-dicarboxylate (1 R1 = Ac, R2 = H 1 g, 4mmol) in Et20 (400 mL) at — 40 C, was evaporated to dryness under reduced pressure. The residue (0.7 g, 2.8 mmol) was dissolved in CHC1, and the solution heated under reflux for 1 h. Evaporation of the solvent yielded the crude product which was purified by column chromatography (silica gel, C,H2C12). The yellow fractions were collected and, after removal of the solvent, the residual oil was distilled in a sublimation apparatus to give 3 (R1 = Ac R2 = H) as a yellow oil yield 0.8 g (80%) bp 50 60 C/5 x 10 4 Torr. 

A solution of the 2-azido ester or amide (ca. 2 g) in a mixture of MeOII (95 mL) and sodium-dried THF (95 mL) was photolyzed under N2 in a Hanovia photochemical reactor (110-W medium-pressure Hg lamp with a Pyrex filter). The reaction was monitored by observing the rate of disappearance of the absorption band (Nf) at 2140 cm 1 (irradiation times of 3-5 h were generally required). When the reaction was complete the solvent was removed in vacuo and the brown residual oil chromatographed on alumina [petroleum ether (bp 60-803C)/benzene 7 3]. Further elution with benzene followed by removal of the solvent gave the product (the esters as pale yellow oils, the amides as crystalline solids), which were further purified by vacuum distillation or by recrysiallization. 

Method A A solution of the azidoquinoline (5 mmol) in 3M KOMe in MeOH (40 mL) and dioxane (40 mL) was irradiated under N2 using a water-cooled, 125-W medium-pressure Hg lamp until all the azide [as measured by the disappearance of u(N3) at 2120 cm" 1 or by TLC] had reacted (4-10h). The photolysate was left to stand at 20 C for 24h then neutralized cautiously by the addition of 4M IICI in MeOH. The solvent was removed under reduced pressure and the crude product was purified initially by column chromatography on alumina (Type H, toluene), then finally by crystallization (petroleum ether). 

Acridine-9-carbonitrile 10-oxide (la 3.00g, 13.6 mmol) in benzene (1.8 L) in a quartz immersion well was irradiated for 3 h with a Hanovia high-pressure 450-W Hg lamp equipped with a Pyrex filter. The resulting solution was evaporated under reduced pressure and the residue was extracted with pentane (3 x 50 mL). The combined extracts were evaporated under reduced pressure at 20 C to give orange crystals yield 1.8 g (60%) mp 105-109 C (Et20/pentane). 

Pyridine-2,6-dicarbonitrile 1-oxide (500 mg, 3.45 mmol) in CH2C12 (500 mL) was irradiated for 10 h with a high-pressure 450-W Hanovia Hg lamp. The solution was evaporated under reduced pressure and the residue was extracted several times with pentane. The combined extracts were concentrated and the residue was repeatedly recrystallized (pentane) to give yellow needles yield 150mg (30%) mp 61-63 C (dec.). 

Methyl-1-phenylisoquinoline 2-oxide (l.OOg, 4.3 mmol) in acetone (200 mL) was irradiated with a Hanovia Q-700 medium-pressure Hg lamp until TLC showed that all starting material had been consumed. The solution was evaporated in vacuo, and the oily residue purified by preparative layer chromatography yield 0.485 g (48.5%) mp 73-75 C. 

Phenylquinoline 1-oxide (10.0 g, 45.2 mmol) in acetone (1.25 L) was irradiated for 12 h with a Hanovia Q-700 medium-pressure Hg lamp, equipped with a Pyrex cooling mantle placed in the center of the reaction vessel, when TLC showed the absence of starting material. The solution was evaporated in vacuo and the residue was extracted with boiling hexane. The extract was evaporated under reduced pressure and the residue was crystallized (pentane) yield 9.0 g (90%) mp 65-66 C. 

A solution of quinoline 1-oxide (0.29 g, 2 mmol) in cyclohexane (1 L) was dehydrated by azeotropic distillation in the reaction vessel. The solution was purged with dry N2 and irradiated with a Hanau high-pressure Hg lamp. The resulting solution was evaporated and the residue was extracted with a little cyclohexane. The insoluble part contained carbostyril (3). The cyclohexane extract was evaporated and the residue purified by short-path distillation at 50°C/0.1 Torr yield 0.174g (60%) moisture-sensitive oil. 

An ice-cold solution of a 3-oxa-6-azatricvclo[3.2.0.02,4]hept-6-ene 1 (0.5-1.0 mmol) in MeCN (200 mL) was irradiated with a 30-W low-pressure Hg lamp for 10-125 min. The solvent was removed under reduced pressure and the residue was treated with active charcoal and hexane/i-Pr20. The mixture was filtered and the filtrate was evaporated under reduced pressure to leave the almost pure 1,4-oxazepines as orange oils, which showed vmal (neat) — 1660-1650 cm-L The products decomposed on attempted chromatography. 

A solution of K.OH (l.l2g, 20mmol) in MeOH (lOmL) was added dropwise over 30 min to a solution of 10a (3.5 g, 10 mmol) in MeOH (350 mL) under irradiation with a 400-W high-pressure Hg lamp with a Pyrex filter. After further irradiation for 1 h, the solution was evaporated under reduced pressure below 30 C, Et20 was added and the solution was washed with sat. brine and then dried (MgS04). Evaporation was followed by chromatography of the residue (alumina, hexane/Et20) yield 1.05 g (70%) red crystals mp 81-8.3 C (i-Pr20). 

The imine 13 (1.0-2.0 g) in benzene or CH2C12 (200-300 mL) was irradiated under N2 in an immersion apparatus equipped with a 400-W high-pressure Hg lamp and a Pyrex filter and cooled internally with running water. When TLC showed that all the starting material had been consumed (1 -3 h) the solvent was removed under reduced pressure and the residue was chromatographed (silica gel. CH2C12). 

The pyridinium salt 3 (0.427 g, 1.81 mmol) in H20 (1 L) was irradiated for 40 min with a high-pressure Hg lamp. The resulting solution was treated with 2M HC1 to pH 1 and then extracted with CHd3 under Nj. The extract was dried (MgS04) and evaporated in vacuo and the residue was chromatographed (silica gel) yield 0.157g (63%) mp 35-39 C. 

A solution of a 3-azidopyridine (0.5-1.0 g) in a mixture of MeOH (75 mL) and dioxane (75 mL) containing NaOMe (2.5-3.0g, large excess) was irradiated under N2 with a 400-W high-pressure Hg lamp with a Pyrcx filter. When TLC indicated that no azidopyridine was left (1 —2 h), the solvents were removed in vacuo, ice-water (10-25 mL) was added to the residue and the mixture was extracted with hexane. The extract was washed with H20, dried and evaporated under reduced pressure and the residue was chromatographed (Sephadex, hexane) to give the products as colorless oils. 

Azido-2-methylquinoline (4, R - Me 0.500 g, 2.7 mmol) and NaOMc (4.0 g. large excess) in a mixture of MeOH (70 mL) and dioxane (70 mL) was irradiated for 30 min with a 400-W high pressure Hg lamp (Pyrex filter). The solvents were removed in vacuo and ice-water (20 mL) was added. The mixture was extracted with CH2C12 and the extract was washed with H20, dried and evaporated. The residue was chromatographed (silica gel, 1 % acetone/CH2Cl2) to give 5a yield 0.194 g (38%) pale-yellow prisms (acetone/hexanes) mp 78-79 C. 

A solution of the quinoxaline 1-oxide (4 mmol) in cyclohexane was degassed by boiling and passing N2 through and irradiated with a medium-pressure water-cooled Hg lamp (Hanau TQ 150), equipped with a Pyrex filter, until conversion was complete. The solvent was evaporated in vacuo at 20 C and the residue was extracted with a small amount of cyclohexane. The product was deposited on strong cooling. Attempted chromatography resulted in the formation of AfW-diacylbenzene-l,2-diamines. 

A solution of the 4-azidopyrimidine 1 or 2-azidopyrazine 3 in MeOH/dioxane (1 1) containing a large excess of Ct2Nll or NaOMe was irradiated with a 400-W high-pressure Hg lamp (Pyrcx) for 20-30 min 10 give ihe product as a viscous oil. No further details were reported. 

The polymer = 8.19 dlg in hexafluoro-2-propanol, HFIP, solution) in Figs 1 and 2 is prepared on photoirradiation by a 500 W super-high-pressure Hg lamp for several hours and subjected to the measurements without purification. The nmr peaks in Fig. 1 (5 9.36, 8.66 and 8.63, pyrazyl 7.35 and 7.23, phenylene 5.00, 4.93, 4.83 and 4.42, cyclobutane 4.05 and 1.10, ester) correspond precisely to the polymer structure which is predicted from the crystal structure of the monomer. The outstanding sharpness of all the peaks in this spectrum indicates that the photoproduct has few defects in its chemical structure. The X-ray patterns of the monomer and polymer in Fig. 2 show that they are nearly comparable to each other in crystallinity. These results indicate a strictly crystal-lattice controlled process for the four-centre-type photopolymerization of the [l OEt] crystal. 

The crystal of 2 OPr recrystallized from EtOH/H20 solution, and the mixed crystal of the same ethyl and propyl cinnamate derivatives (2 OEt and 2 OPr), on photoirradiation for 2h at room temperature with a 500 W super-high-pressure Hg lamp, afforded the highly strained tricyclic [2.2] paracyclophane (2 OEt-2 OPr-cyclo) crystal quantitatively (Maekawa et ai, 1991b). A crystal structure analysis was carried out of a single crystal of the complex of 2 OEt-2 OPr-cyclo with HFIP (recrystallization solvent) in a 1 2 molar ratio. Fig. 13 shows the molecular structure of 2 OEt-2 OPr-cyclo viewed along the phenylene planes. The short non-bonded distances and deformation of the benzene rings, as seen in Fig. 13, are common to those of [2.2] paracyclophanes, as previously reported (Hope et ai, 1972a,b). 

Fig. 6. UV-Vis absorption spectral change of trans-25 (0.126 mM) in acetonitrile under a nitrogen atmosphere upon photoirradiation with three bright lines (Amaj[ = 365, 436, and 546, nm) of a super-high-pressure Hg lamp. The spectra are depicted at 10 min intervals of photoirradiation. The irradiation with each bright line was continued for 30 min in ascending order of wavelength. (Reprinted with permission from Ref. 153.)...

When a thin liquid film with a thickness of approximately 2 pm prepared by spin coating of a 15% benzene solution of polymer 1 was irradiated with a 500-W Xe-Hg lamp for 300 s in air, a transparent solid film was obtained. The UV spectrum of this solid film shows that an absorption at 235 nm due to phenyldisilanyl units vanishes after UV-irradiation (Figure 1). This clearly indicates that photolytic cleavage of silicon-silicon bonds leading to the cross-linking occurred. Similar photolysis of the thin liquid films under a nitrogen atmosphere again afforded transparent solid films whose UV spectra show no absorption at 235 nm due to phenyldisilanyl units. 

Scheme 8. Wiger and Rettig synthesis of JV-carbethoxynortropidine (159). Reagents i, v Hg lamp ii, PdCl2(PhCN)2, C6H6, RT, 60 hr.

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