Alcohols, 1,2-azido synthesis

Ceroplastol synthesis, 1, 428 Cetyl alcohol synthesis, 1, 478 Chaetoglobasins structures, 4, 376 Chalcone, o -azido-2 -oxy-synthesis, 3, 823 Chalcone, 2-hydroxy-reduction, 3, 751 Chalcone, 2 -hydroxy-mass spectra, 3, 618 Chalcone dibromides flavone synthesis from, 3, 823 Chalcones polymers, 1, 304 Chanoclavine synthesis, 6, 423 Charge density waves in stacks of ions, 1, 351-352 Chartreusin... 

Synthesis of azindines Irom epoxides via amino alcohols or azido alcohols and reaction with phosphines or phosphites... 

By combining several click reactions, click chemistry allows for the rapid synthesis of useful new compounds of high complexity and combinatorial libraries. The 2-type reaction of the azide ion with a variety of epoxides to give azido alcohols has been exploited extensively in click chemistry. First of all, azido alcohols can be converted into amino alcohols upon reduction.70 On the other hand, aliphatic azides are quite stable toward a number of other standard organic synthesis conditions (orthogonality), but readily undergo 1,3-dipolar cycloaddition with alkynes. An example of the sequential reactions of... 

Azido derivatives of furazans have proved to be particularly useful for the synthesis of heterocyclic systems. Thus, by 1,3-dipolar addition of l-azido(4-amino-l,2,5-oxadiazol-3-yl)aldoxime 186 to propargyl alcohol and phenylacetyl-ene, bicyclic 4-amino-l,2,5-oxadiazol-3-yl(4-R-l,2,3-triazol-l-yl)ketoximes 187 were obtained (Equation 34) which in reaction with acetic anhydride afforded the corresponding 0-acyl derivatives <2003RJ0574>. 

The synthesis of the amino alcohol (5S,6S)-6-amino-5-decanol begins with reaction of the 1-chloropentylboronic ester (Section 1.1.2.1.3.1.) with sodium azide under phase-transfer conditions to form the a-azido boronic ester, which yields the a-chloro- -azidoalkyl boronic ester (1) [yield 92 % 95 % de] with (dichloromethyl)lithium under the usual conditions. The reaction of 1 with butylmagnesium chloride is unusual in that it requires zinc chloride in order to accomplish the replacement of chlorine by butyl to form /J-azidoalkyl boronic ester 2 without boron-azide /1-elimination. Standard peroxidic deboronation and reduction of the azide complete the synthesis15. 

Based on this sequence, Blum et a/.158 have reported a general synthesis of unsubstituted K-region arene imines from the corresponding arene oxides. K-Imines of benz[a] anthracene, 7-methylbenz[a]anthracene, dibenz [a,/i] anthracene, and benzo[a] pyrene have been prepared. Azido alcohol formation from these oxides is generally nonregiospecific and both possible regioisomers of the azido alcohols are formed in different proportions. 

Advantageous use of homochiral cyclohexadiene-cis-l,2-diol, available by means of biocatalytic oxidation of chlorobenzene with toluene dioxygenase, has enabled the synthesis of all four enantiomerically pure C18-sphingosines (Nugent, 1998), which are known inhibitors of protein kinase C and important in cellular response mediation for tumor promoters and growth factors. The four requisite diastere-omers of azido alcohol precursors were accessed by regioselective opening of epoxides with either azide or halide ions. 

Variously substituted 2-azido-pyridines have been irradiated on a preparative scale in the presence of alcohols or amines for the synthesis of the corresponding variously substituted 1,3-diazepines, in good to high yields. In the presence of halo substituents on the pyridinium moiety, a nucleophilic substitution by the ZH reagent can also occur [93]. Among others, representative examples of obtained target are reported in Figure 12.1 [91, 93]. 

Various dialkyl- and diaryl(vinyl)sulfonium salts react with l//-indole-2-carbaldehyde in the presence of NaH to form a tetracyclic oxirane, for example, 167 these upon treatment with sodium azide form tricyclic azido alcohols analogous to compound 168 in 72% yield (Scheme 35) <1999T10659>. This annulation was a key step in total synthesis of Mitomycin K <1996TL6049>. 

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