Nitro Methylene Blue

A few nitro derivatives of methylene blue have been described. By introducing one nitro group under mild conditions (nitric acid of ca. 20% and sodium nitrite) methylene green was obtained [85]. 

According to Gnehm [86] methylene blue, when subjected to the action of nitric acid (density 1.33, i.e. 52%) in presence of acetic acid diluted to 50%, yields dinitrodimethylthionine nitrate of suggested structure (I). 

According to the author mentioned, one of the two dimethylamino groups was fully demethylated. 

Experiments carried out by T. Urbanski, Szyc-Lewanska and Kalinowski [87] suggest the structure of 2,4-dinitro-3-(methyl)nitramino-7-(dimethyl)amino-5,5-dioxyphenothiazine (II) for the Gnehm product. The phenol produced by alkaline hydrolysis has the structure of 2,4-dinitro-3-hydroxy-7-(dimethyl)amino-5,5-dioxy-phenothiazine (III) 

According to the same authors [87] energetic nitration of methylene blue may yield 2,4,6,8-tetranitro-3,7-di(methylnitramino)-5,5-dioxyphenothiazine (IV). This substance, when warmed with a 2% solution of NaOH, underwent the usual hydrolysis of the nitroamino group, placed in ortho position, to two nitro groups and yielded phenol (V). 

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Methylene Green (mol. wt. 364.6). Methylene Green is a nitro methylene blue and its reduction requires 6 equivalents of iron. Therefore,. cc. titanium trichloride solution is equivalent to ... 

Trinitrophenyl-P-hydroxynitraminoethyl nitrate (peniryl. pentyl) Hexanitrodiphenyl-f3 hydruxynitrarrinocihyl nitrate Nitraminonitrophenols Nicramino-azoxy compounds Nitro methylene blue Literature... 

In a series of studies conducted in our laboratory (Ignarro et al., 1990b Rajfer et al., 1992), relaxation of corpus cavemosum smooth muscle from the penis of the rabbit and human caused by electrical stimulation of the NANG neuronal pathway was found to be inhibited by oxyhemoglobin, methylene blue, N°-nitro-... 

Methylene green, the nitro derivative of methylene blue, is an interesting dye. The nitration is effected in the same way as that of tropaeo-line, using the crude zinc chloride double salt without further treatment. 

Continuing the work of Gnehm on the nitration of methylene blue, Urbanski et ai. obtained a higher nitrated product, to which structure 166 was assigned in both dimethylamino groups, one of the methyls has been replaced by a nitro group. Hydrolysis to the phenolic compound (167) was taken as evidence for the proposed structure. If this is correct, Gnehm s nitration product, which is an intermediate in the formation of 166, must also have an N-methylnitramine structure. 

This compound is obtained by treating methylene blue with nitrous acid. It dyes textile fibres a fine dark green colour, and appears, from its properties, to be a nitro-derivative of methylene blue. In its behaviour towards fibres it resembles. the latter. 

Plasma nitrobenzene levels are not clinically useful. The metabolites in urine, p-nitro- and p-aminophe-nol, primarily in long-term exposure to nitrobenzene can be used as evidence of exposure. Methemoglobin levels should be determined in all cyanotic patients cyanosis that does not respond to oxygen therapy may appear when the plasma methemoglobin level is 15%. Symptomatic methemoglobinemia should be treated with methylene blue. For seizures, diazepam should be administered via an intravenous bolus. 

We have shown38 that 8-methoxy-6-nitro-BIPS (11) is the only photochrome able to sensitize the formation of (h with a quantum yield A = 0.15 that is about one-fourth that of a commonly used singlet-oxygen sensitizer, i.e. methylene blue, for which 0A = 0.57.39 This benzopyran behaves as a good quencher of l02 as well. Unfortunately, in the paper by Guglielmetti and co-workers an analysis of the... 

The oxidation of steroidal 3a-, 3)5-, 20a-, and 20j8-amines with m-chloroper-benzoic acid to the corresponding nitro-compounds has been described. Oxidation of several steroidal tertiary amines with chromic acid in pyridine leads to the corresponding N-formyl derivatives. Photosensitised irradiation (methylene blue) of 20a- and 3)5-dimethylamino-steroids leads to a secondary amine in 80% yield. The formyl derivative (10% yield) is not an intermediate in the N-demethylation reaction. 3a-Dimethylamino-5a-pregnane gives 5a-pregnan-3-one and the secondary amine. Conanine gives the lactam (50). ... 

Systemic administration of the specific NOS inhibitor 7-nitroindazole (50 mg/kg i.p.) and the non-selective inhibitor of guanylate cyclase and NOS, methylene blue (30 mg/kg s.c.) increased the extracellular levels of 5-hydroxytryptamine and dopamine in the rat ventral hippocampus ( Volke et al. 2000). Local administration (via the microdialysis probe) of citalopram (1 iM), paroxetine (2 p.M), ti-aneptine (2 iM) and imipramine (20 iM) produced a significant decrease in the levels of [ H]l-dtrulline compared to the control activity (Wegener et al. 2000). In contrast, 5-hydroxytryptamine (20 nM) failed to influence the levels of [ H]l-citrulline. Reverse dialysis with the NOS inhibitor, N -nitro-L-arginine (2 mM), also decreased the levels of [ H]L-citrulline (P <0.05). The NOS activity in vitro was unaffected by citalopram, paroxetine, tianeptine, imipramine and 5-hydroxytryptamine in the concentrations used in vivo, but showed a significant decrease after administration of N -nitro-L-arginine (P <0.05). 

The solvent system was generally composed of nitro-methane, formic acid, and benzene, 50 1 5, and the indicator was a mixture of quinaldine red and methylene blue in anhydrous methanol. The end point was signified by a green color. 

PNVC has been modified chemically to incorporate substituents on the carbazole groups, (2). Methylene blue sensitizer can be bonded to sulfonated PNVC. Bonded nitro- and cyano-groups act as acceptors giving rise to enhanced photoconductivity. Antimony pentachloride produces cross-... 

Amino-6-nitro-Fischer s base (36, R = N02) was reduced to the 5,6-diamino compound (36, R = NH2) in 80% yield, which (as its hexachlorostannate salt) was condensed with benzoic acid and with benzil to give, respectively, a 68% yield of 5,7,7-trimethyl-6-methylene-6,7-dihydro-5 7/-pyrrolo[2,3-/]-benzimidazole (37) and a 62% yield of 6,8,8-trimethyl-7-methylene-2,3-diphenyl-7,8-dihydro-6 7/-pyrrolo[2,3-g]quinoxaline (38).42 Spiropyrans from these linearly annellated Fischer s bases were not reported they likely would color upon irradiation with blue light. 

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