Search

Phenylthiourea (PTU) is well known as bioactive compound and one of the reversible inhibitors for tyrosinase. Tyrosinase plays very important roles for tyrosine metabolisms to maintain the skin homeostasis from sunlight with forming melanin. Synthesis of photoaffinity label reagents of PTU will be attractive thesis to elucidate functional analysis for tyrosinase.

Organic azide complexes [Os(η5-C5H5)(κ1-N3R)(PPh3){P(OR1)3}]BPh4 (1, 2) [R = CH2C6H5 (a), CH2C6H4-4-CH3 (b), CH(CH3)C6H5 (c), C6H5 (d); R1 = Me (1), Et (2)] were prepared by allowing bromo-compounds [OsBr(η5-C5H5)(PPh3){P(OR1)3}] to react first with AgOTf and then with an excess of azide in toluene. Benzylazide complexes reacted in solution leading to imine derivatives [Os(η5-C5H5){κ1-NH[double bond, length as m-dash]C(R2)Ar}(PPh3){P(OR1)3}]BPh4 (3, 4) [R2 = H (a, b), CH3 (c); Ar = C6H5, C6H4-4-CH3; R1 = Me (3), Et (4)]. Phenylazide, on the other hand, reacted in solution affording the dinuclear dinitrogen complex [{Os(η5-C5H5)(PPh3)[P(OMe)3]}2(μ-N2)](BPh4)2 (5). Depending on the nature of the R substituent, the reaction of the p-cymene complex [OsCl2(η6-p-cymene)(PPh3){P(OEt)3}] with RN3 yielded imine [OsCl(η6-p-cymene){κ1-NH[double bond, length as m-dash]C(H)Ar}{P(OEt)3}]BPh4 (6) (Ar = C6H4-4-CH3) and amine derivatives [OsCl(η6-p-cymene)(κ1-NH2C6H5){P(OEt)3}]BPh4 (7). The complexes were characterised spectroscopically (IR, 1H, 31P, 15N NMR) and by the X-ray crystal structure determination of [{Os(η5-C5H5)(PPh3)[P(OMe)3]}2(μ-N2)](BPh4)2 (5).

Synthesis of cross-linkable diketopiperadine derivatives is described. Cross-linkable a-amino acid methyl esters were subjected to peptide synthesis with Boc-protected glycine or L-tyrosine. No protection of cross-linkable functional groups (catechol and phenylazide) is necessary for the construction of diketopiperazine skeleton.

A microwave-assisted synthesis of 2-(4-((1-phenyl-1H-1,2,3-triazol-4-yl)methoxy)phenyl)-1H-benzo[d]imidazoles from a phenylazide, propargyloxybenzaldehyde and a 1,2-diaminobenzene is proposed.

The reactions of alkynes and α-nitro-olefines with methylazide and phenylazide was studied. In contrast to known reactions with alkynes which are non-regioselective, methylazide and phenylazide react regiospecifically with α-nitro-olefines and give only one type of triazole after elimination of HNO2. These reactions are very useful synthetic approaches to 1,2,3 triazoles.

Phenylazide and methylazide reacts with title olefines and gives two isomeric triazoles without nitro group, and 4-nitro-1,2,3 triazole. The isomerisation of starting alkenes explains the formation of isomeric triazoles. Oxydation of amino-nitro-diazocompounds in equilibrium with 1,2,3 triazolines leads to 4-nitro-1,2,3 triazoles.

1,3-Dipolar addition was investigated of 2-azidoethanol to diyne glycols containing primary or tertiary hydroxyethyl groups at the system of triple bonds. This reaction provided exclusively a monoadduct as a single regioisomer, namely, 5-alkynyl-1,2,3-triazole.

Practical method of synthesis of the 1,4-dioxane derivative of the closo-dodecaborate anion was developed. The cleavage of the dioxonium ring in [B12H11O(CH2CH2)2O]− with acetylenic alcohols gave rise to the preparation of closo-dodecaborate derivatives with terminal acetylene group. These compounds can be introduced into click reactions with phenylazide leading to the corresponding triazoles. The structures of (Bu4N)[B12H11O(CH2CH2)2O] and (Bu4N)2[B12H11(OCH2CH2)2OCH2C CH] · 0.5HOCH2C CH were determined by single-crystal X-ray diffraction.

The molecular structure, vibrational spectra, tautomerism and photochemistry of the derivative of tetrazole, 1-phenyl-tetrazolone (C7H6N4O;PT) have been studied by FT-IR matrix isolation spectroscopy and DFT/B3LYP/6-311++G(d,p) calculations. Among the five structures in which PT could be expected to exist (two keto tautomers, one mesoionic olate-form and two different conformers of the hydroxyl tautomer), only the most stable species, 1-phenyl-1,4-dihydro-5H-tetrazol-5-one, could be experimentally observed in low temperature argon matrices. Monomers of this tautomer give rise to an IR spectrum that fits nicely the calculated spectrum obtained at the DFT/B3LYP/6-311++G(d,p) level of theory. In situ UV irradiation (λ > 235 nm) of the matrix-isolated PT induces three main photochemical processes, all of them involving cleavage of the tetrazolering: e.g. (1) molecular nitrogen loss, with production of 1-phenyl- diaziridin-3-one; this compound reacts subsequently to form 1-aza-1,2,4,6- cycloheptatetraene and isocyanic acid (eventually, also to form CO plus phenyldiazene); (2) cleavage of the C(5)–N(1) and N(3)–N(4) tetrazole-ring bonds, with production of phenylazide and isocyanic acid, with phenylazide then losingN2 to yield as final product 1-aza-1,2,4,6-cycloheptatetraene; and (3) cleavage of the N(1)–N(2) and N(4)–C(5) tetrazole-ring bonds, to yield phenylisocyanate and azide. The observed photochemical processes are distinct from the preferred thermal fragmentation channel, where CO is produced together with a weak IR absorbant species. Fil: Gomez Zavaglia, Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Universidad de Coimbra; Portugal. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina Fil: Reva, Igor D.. Universidad de Coimbra; Portugal Fil: Frija, Luis M.T.. Universidad de Algarve; Portugal Fil: Cristiano, María Lurdes. Universidad de Algarve; Portugal Fil: Fausto, Rui. Universidad de Coimbra; Portugal

A chain of photoinduced transformations of a photosensitively labeled crown ether (p-azido-benzo-18-crown-6) is studied in organic solvent and water to estimate the radiation dozes needed for optimum binding of photolabel. Transient absorption spectra of p-azido-benzo-18-crown-6 are measured with picosecond time resolution. The well-known photoinduced dynamics of phenylazide is compared to the dynamics of p-azido-benzo-18-crown-6.

Large Photoinduced Refractive Index Increase in Polymer Films Containing Phenylazide Maintaining Their Transparency and Thermal Stability

The reaction of C5H5Rh(CO)(PiPr3) (1] which is prepared from C5H5Rh(CO)2 and neat P1Pr3, with the nitriloxides 2-RC6H4CNO (R  H, Cl) leads to the formation of the metallaheterocycles C5H5(P1Pr3) RhC(O) ONC(C 6 H 4 R ) (2, 3) in 90–95% yield. Compound 1 reacts with tosylazide to give the C,N-bound isocyanate complex C5 H5(PiPr3)Rh(η2-TosNCO) (6). Analogously, on treatment of C5Me5Co(CO)(PMe3) with phenylazide the phenylisocyanate derivative C5Me5(PMe3)Co(η2-PhNCO) (7) is formed. Protonation of 7 with CF3CO 2H affords the non-ionic carbamoylcobalt complex C5Me5(PMe3)Co[C(O)NHPh](O2CCF3) (8). The X-ray structural analysis of 2 reveals the presence of an almost planar RhCONC heterocycle in which the two Rh-C distances differ by 0.045 A

Die Oxydation von RN(PF2)2 mit N2O4 in n-Hexan fuhrt in guten Ausbeuten zu den Bis(difluorophosphoryl)-amiden RN(POF2)2 (R = Me, Et). Mit Phenylazid wird nur ein Phosphoratom oxydiert und es werden 1,3-Diphenyl-2,4-bis(difluorophosphor(III)-N-alkylamido)-2,2,4,4-tetrafluoro-diaza-λ5,λ5-diphosphetidine, [F2PN(R)PF2NPh]2, erhalten. Investigations on the Oxidation of N-Alkyl-bis(difluoro-phosphorus(III))amides Oxidation of RN(PF2)2 by N2O4 in n-hexane leads to bis(difluorophosphoryl)amides, RN(POF2)2 (R = Me, Et), in good yields. Only one phosphorus atom is oxidized by phenylazide resulting in the formation of 1.3-diphenyl-2.4-bis(difluorophosphorus(III)-N-alkyl-amido)-2.2.4.4-tetrafluoro-diaza-λ5,λ5 diphosphetidines, [F2PN(R)PF2NPh]2.

Die disubstituierten Cyanthioformamide 1 addieren sich an Diazoverbindungen, vermutlich unter Bildung der Thiadiazole 2, die weiter zu den Thiiranen 3 zerfallen. Diese konnen zu den Ethylenen 5 entschwefelt werden. Mit Diphylnitrilimin bildet 1b das Thiadiazolin 6. Nitriloxide liefern mit 1 die Oxathiazole 7. In gleicher Weise ergeben die monosubstituierten Cyanthioformamide 8 die Oxathiazole 9, die weiter in Arylisothiocyanate und die Cyanformamide 10 zerfallen. Die Reaktion von 1 mit Phenylazid bei 100°C liefert, offenbar uber die instabilen Thiatriazoline 11 oder 12 und die Thiaziridine 13, die Cyanformamidine 14. Cycloadditions of Cyanothioformamides with 1,3-Dipoles The disubstituted cyanothioformamides 1 add to diazo compounds presumably forming the thiadiazoles 2 which decompose to give the thiiranes 3. These may be desulfurized to the ethylenes 5.1b reacts with diphenylnitrilimine to form the thiadiazoline 6. Nitrile oxides and 1 afford the oxathiazoles 7. The monosubstituted cyanothiaoformamides 8. likewise yield the oxathiazoles 9. which decompose to aryl isothiocyanates and the cyanoformamides 10. The reaction of 1 with phenylazide at 100°C produces the cyanoformamidines 14. probably via the unstable thiatriazolines 11 or 12 and the thiaziridines 13.

The photolysis of anthranils (III) led to ring enlargement with the formation of 3-acyl-2-methoxy-3 H -azepines (IV). The reaction in ether containing water or amines yielded the corresponding 2-oxo- or 2-amino-3 H -azepines (V or VII). On the other hand, photolysis of some 7-substituted 3-phenylanthranils (IX and XIII) gave the corresponding 9-acridanone derivatives (X and XIV). A hypothetical scheme (anthranil → nitrene → azirene → azepine) similar to that proposed by Huisgen and Appl for the analogous ring enlargement of phenylazide is applicable to the anthranil rearrangement. By UV and IR spectroscopic methods, the last step was proved to involve a dark reaction of an intermediate (probably azirene species) with protic solvents.

The fascinating carbene‐nitrene rearrangement can be observed directly by ESR spectroscopy. In the thermal decomposition of the carbene precursor 4 (via 3) with subsequent matrix isolation, the product gave the same ESR signal as phenylnitrene 2 from phenylazide 1! In the aza‐analogous system, the seven‐membered carbene 5 is probably formed as intermediate of the rearrangemet. (Figure Presented.)

The photoactivable compound phenylazide interacts reversibly with the frog's olfactory epithelium when delivered as an olfactory stimulus. Its application together with UV irradiation resulted in a differential reduction of the responses (electro-olfactogram) to several odorants. It was found that this chemical modification of the sensory membrane affected the responses in relative ratios which could be predicted from a classification of the odorants based upon independent studies of receptor cell odor sensitivity. The responses to chemicals representative of the ‘aromatic group’ were clearly more reduced than those to compounds of the ‘camphoraceous group’. It is suggested that the olfactory discrimination mechanisms can be approached by the use of this method.

WE have just seen Dr. Sutton's communication on the “Structure of the Azides, from their Electric Dipole Moments”.1 We also have measured the dipole moments of phenylazide, p-chlorphenylazide, and p-bromphenylazide and found the values 1.55, 0.47, and 0.64 × 10â18 e.s.u., respectively, in good agreement with Dr. Sutton's data. We believe that the moments for the two halogeno-compounds are really zero or very small, because we must neglect their atomic polarisation. The moment of the molecule is, therefore, the vectorial sum of the moments of the substituents.