Azido groups

Dichloropyridazine 1-Oxide produces both isomers with alkoxides. However, the ratio is dependent on the size of the alkoxy group. In the reaction with sodium methoxide 80% of 6-chloro-3-methoxypyridazine 1-oxide and 7.5% of 3-chloro-6-methoxypyridazine 1-oxide are formed. Similar results are also obtained with sodium ethoxide, while sodium propoxide affords only 6-chloro-3-propoxypyridazine 1-oxide. Amines react similarly, while only chlorine at the 3-position can be substituted with an azido group to give 3-azido-6-chloropyridazine 1-oxide. 

When 6-amino-3-chloropyridazine 1-oxide is diazotized in 50% sulfuric acid, 6-hydroxy-3-pyridazinediazonium anhydro salt is formed. An azido group at either position in pyridazine A-oxides can readily be replaced with sodium alkoxides. 

The two NH2 stretching vibrations of aminopyrazoles follow the Bellamy-Williams relation [r-jlNH) = 345.5-0.876r <,s(NH)] (76AHC(Sl)l) establishing the amino tautomeric structure of (91). Azidopyrazoles also show the Vs and Vas bands of the azido group. The... 

Azidopyrazoles (455) exist as such even when the azido group is at the 3-position where an azido-tetrazole equilibrium is possible (469) (470) (77AHC(2l)72, 78AHC(22)184). 

Relatively little work has been done on displacement of the azido group on benzenes ° (by hydroxide, ammonia, amines, or hydrazine) or on heterocycles. The latter involve reaction of... 

In contrast to the 2,4-diazidopyrimidines, only one azido group is involved in ring-chain transformations of 4,6-diazidopyrimidine 342 (Scheme 134) (88DOK115).The content of the tetrazole tautomer 342AT increases... 

The azido complex [(T) -Cp )(N3)Rh( j.-N3),Rh(N3)(Ti -Cp )] with trifluoroace-tonitrile gives the tetrazole complex with two terminal and one bridging tetrazolate ligands as well as one unreacted bridging azido group, 193... 

Among other bicyclic amidine catalysts, 3,4,6,7,8,9-hexahydro-2//-pyrido[l,2-n]pyrimidine was also applied in the preparation of /3-alkoxy nitriles from Q ,/3-unsaturated nitriles and alcohols (99GEP 19803515). The azido group could be smoothly converted into a trifluoroacetylamido group by treatment with (Cp3CO)2 in the presence of Ph3P and 2,3-dihydro-2//-pyrido[l,2-n]pyrimidin-2-one under Ar in THE (99HCA2380). 

The infrared spectrum of this substance showed the presence of an azido group and a 0-lactam system. The substance inhibited the growth of Staph, aureus Oxford at a concentration of 0.25 mcg/ml. 

Ethoxycarbonyloxyethyl 6-(D-a-azidophenylacetamido)penicillinate (98 g) was prepared from sodium 6-(D-a-azidophenylacetamido]penicillinate (397 g, 1 mol), a-chlorodiethylcar-bonate (458 g, 3 mols) and sodium bicarbonate (504 g, 6 molsl. The product showed strong IR absorption at 2090 cm- and 1 780-1750 cm" showing the presence of azido group and /3-lactam and ester carbonyls. 

The syntheses were effected by selective mesylation of one or two hydroxyl groups and displacement of each mesyloxy group by an azido group, which was reduced to amino. Although attempted SN2 displacement of cyclohexane substituents is often unsuccessful, the powerfully nucleophilic azide ion is usually able to displace an alkylsulfonoxy group, and this route has been exploited in several recent cyclitol syntheses. 

Molar Refraction. The molar refraction of the azido group in alkyl azides was estd to be ca 9,4 (Ref 14). For a discussion of molar refraction see Ref 9, p 528... 

Glowiak (Ref 5) claims that detonation velocity, heat of combustion and Trauzl Block test all correlate with a true OB for 25 nitro compounds (some containing diazo or azido groups). This writer has not seen his original publication CA does not specify intelligibly what is meant by true OB... 

Dediazoniation refers to all those reactions of diazo and diazonium compounds in which an N2 molecule is one of the products. The designation of the entering group precedes the term dediazoniation, e. g., azido-de-diazoniation for the substitution of the diazonio group by an azido group, or aryl-de-diazoniation for a Gomberg-Bachmann reaction. The IUPAC system says nothing about the mechanism of a reaction (see Sec. 1.2). For example, the first of the two dediazoniations mentioned is a heterolytic substitution, whereas the second is a homolytic substitution. 

The chemistry of the azido group The chemistry of the acyl halides The chemistry of the carbon-halogen bond (2 parts)... 

The Chemistry of the Azido Group The Chemistry of Acyl Halides... 

This approach has been recently extended to the reduction of aromatic azides using EtsSiH, which afford anilinosilanes and hence the corresponding anilines in virtually quantitative yields (Reaction 38). The EtsSi radical adds to the aromatic azido group to give an N-silylarylaminyl radical presumably through loss of nitrogen. Eventual reduction of the silylarylaminyl radical by ferf-dodecanethiol affords N-silylaniline 31, the hydrolytic precursors of the final anilines. 

Two azido groups can be added to double bonds by treatment with sodium azide and iodosobenzene in acetic acid." ... 

C-methyl group or 4 -C-azido group in nucleoside analogues targeting the hepatitis C virus (HCV) RNA polymerase NS5B. 

How do these NRRIs interact with their final target, the HCV RNA replicase They are phosphorylated to their 5 -triphosphate form, and then inhibit the HCV replicase. As they possess a 3 -hydroxyl function, they may not be considered as obligate chain terminators, but they may act as virtual chain terminators, viz. by steric hindrance exerted by the neighboring 2 -C-methyl and/or 4 -C-azido groups. Similar to their NRTI and NNRTI counterparts in the case of HIV reverse transcriptase, the NRRIs (2 -C-methylnucleosides) interact, upon their phosphorylation to the corresponding 5 -triphosphates, with a region of the HCV RNA replicase (or NS5B RNA-dependent RNA polymerase) that is clearly distinct from the site(s) of interaction of the NNRRIs (Tomei et al. 2005). 

Ketenes also add to imines in 2 + 2 cycloadditions giving the important g-lactams (20). The reglochemistry is predictable as the nitrogen is the nucleophilic atom in the imine. This is true even in conjugated imine (21) which gives (22) with azidoketene. The azido group can... 

Paulsen and his coworkers first synthesized (-f-)-203 from L-quebrachitol (286) by a 21-step reaction as follows. The di-O-isopropylidene derivative was oxidized to the ketone (287), and then epoxidized with dimethyl sulfox-onium-methylide to give 288, which was subjected to benzoylation, mesyla-tion, and demethylation, followed by benzylation, to afford 289. Introduction of unsaturation was accomplished by epoxidation of 289 with sodium methoxide to 290 and 291, and deoxygenation to 292. The azido group was introduced with azobis(dicarboxylate) to give 293, which was hydrogeno-lyzed, followed by deprotection to afford 203. 

Kuzuhara and his coworkers synthesized (+)-205 by hydroxylation of the alkene 304, which was prepared from the chiral azidocyclohexene derivative (303) derived from D-glucose, in which a novel rearrangement of the C - C double bond accompanying reduction of the azido group with lithium aluminum hydride was observed. 

In contrast to diazido compounds [102] and [104], which throw off two azido groups and form silylene and germylene, photodecomposition of silyl azide [105] led to the generation of aminosilylene [107] via isomerization of initially formed nitrene [106] (Maier et al., 1989b). The IR spectrum of the... 

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