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A number of vicinal cyclic diketones, most of them belonging to the 1,2-indanedione series, have been prepared and tested as potential reagents for latent fingerprint development. Unsubstituted 1,2-indanedione and a number of its mono- and dimethoxy- derivatives exhibited excellent properties as fluorogenic reagents for latent prints on paper. Structural modifications, such as substitutions at position 3, omission of the benzene ring or increase of the five-membered to a six-membered ring, considerably reduced this activity. Quite surprisingly, benzo[f]indane-1,2-dione, which was synthesized for the first time in this work, was significantly inferior to 1,2-indanedione as a fingerprint reagent.
Even at this stage, before optimization of the reaction conditions, it can be said that some 1,2-indanediones are at least as sensitive as DFO. Their solubility in nonpolar solvents and relative case of preparation are further advantages. It is the authors' opinion that 1,2-indanedione itself may soon become a practical fingerprint reagent.
HOF◊CH 3 CN, probably the best oxygen transfer agent organic chemistry has to offer, is easily made by bubbling diluted fluorine (10-15%) through aqueous acetonitrile solution. Used as formed without any isolation or purification, it reacts with various tertiary amines such as pyridine derivatives, polyaromatic nitrogen containing compounds and aliphatic and alicyclic ones to form the corresponding N-oxides. When two nitrogen atoms are present it is possible to make both the N-monoxides and the N,N-dioxides. The reaction times are short (a few minutes), conditions are very mild (0-25°C) and the yields range from good to excellent (70-95%).Tertiary amine N-oxides are a class of compounds which assumes increasing importance. They are used in a variety of processes as well as final products such as fiber preparation, 1 hair tonics, 2 topical pharmaceuticals, 3 and cellulose solvents. 4 The increased attention these compounds are receiving encouraged us to examine their preparation by using one of the best oxygen transfer agents organic chemistry has to offer, the HOF◊CH 3 CN complex.The preparation of this reagent, first introduced by us some years ago, 5 is quite simple. Its solution is formed in good yields by passing nitrogen-diluted fluorine through aqueous acetonitrile. The HOF◊CH 3 CN complex is used as obtained and does not require any isolation or purification. It is able to transfer an oxygen atom under mild conditions even to very weak nucleophiles. In the past we have demonstrated its ability to epoxidize normal 6 and very electron deficient alkenes, 7 oxidize amines, 8 ethers, 9 a variety of sulfides, 10 and much more. 11 We report here yet another of its fast and efficient reactions, this time with tertiary amines forming the corresponding N-oxides. It should be noted that although some of the N-oxides had been previously prepared, the combination of the very mild conditions and short reaction times gave in most cases better results than those reported in the literature. 12Pyridines react quickly at temperatures ranging from 0 to 25°C to produce the N-oxide compounds in good yields. Pyridine (1) itself was transformed into its N-oxide derivative 2 in 85% yield within less than five minutes. Similarly 3-and 4-methylpyridines 3 and 4 were converted to the corresponding N-oxides 5 and 6 in high yields. Rings substituted with strong electron-donating groups such as 2-methoxypyridine 13 (7) or with electron-withdrawing ones such as 2-cyano-(8), 3-acetyl-(9) and 2-chloropyridine (10) also proved to be excellent substrates producing the respective N-oxides 11-14 in good yields. Although we had already demonstrated that double bonds react with HOF◊CH 3 CN to form epoxides 11 the nitrogen atom of the pyridine is activated first. Thus 4-vinylpyridine (15) was converted in 70% yield to the corresponding N-oxide 16 without affecting the alkene. Another interesting example is 4-(N,N-dimethylamino)pyridine (17) with its two tertiary nitrogen atoms. Under the mild reaction conditions applied, only the ring-nitrogen at...
For more than 50 years the synthesis of 1,10-phenanthroline-N,N'-dioxide (2) has been sought. The reason for the failure of all the earlier attempts is that the limited space in the bay area of the starting material 1,10-phenanthroline (1) cannot accommodate two oxygen atoms. The oxidation has now been achieved with the oxygen-transfer agent HOF small middle dotCH(3)CN, and X-ray studies have revealed that the product is not planar but is a new type of helicene-in this way the "space problem" for the two oxygen atoms has been solved.
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