Epoxy azide

One such strategy exploits 142 for construction of the heterodiene 149, derived from azide 148, in which the stereochemistry of the intramolecular Diels—Alder cycloadducts is controlled by the configuration of the dienophile olefin. Treatment of 142 with diphenylpho-sphoryl azide in the presence of diisopropyl azodicarboxylate and triphenylphosphine affords the epoxy azide 148 with inversion of chirality. This is then converted in six steps to the heterodiene intermediate 149, which undergoes an intramolecular cycloaddition to fiimish a single adduct that is subsequently converted to 150. Transformation of 150 into 151 in seven steps completes the synthesis [59] (Scheme 36). 

A recent interesting example in this area is the rearrangement of epoxy azide 18 which, on exposure to triethylphosphine and after liberation of nitrogen gas, underwent the aza-Payne rearrangement fScheme 10.51. In this case, EtgP was responsible for successful stabilization of the reactive nitrogen species by formation of an aza-ylide intermediate, enabling the direct synthesis of N—H aziridine 19. 

Both saturated (50) and unsaturated derivatives (51) are easily accepted by lipases and esterases. Lipase P from Amano resolves azide (52) or naphthyl (53) derivatives with good yields and excellent selectivity. PPL-catalyzed resolution of glycidyl esters (54) is of great synthetic utiUty because it provides an alternative to the Sharpless epoxidation route for the synthesis of P-blockers. The optical purity of glycidyl esters strongly depends on the stmcture of the acyl moiety the hydrolysis of propyl and butyl derivatives of epoxy alcohols results ia esters with ee > 95% (30). 

Although chlorine azide and bromine azide tend to give some dihalogen adducts, these reagents have been used in the presence of alcohol, ester and epoxy functions without interference.In the case of 17a-acetoxy-A -progesterone, a selective addition to the 6,7-double bond is obtained. ... 

Watt and coworkers139 prepared the a-azidoaldehydes (242) by nucleophilic ring opening with sulfinate ion expulsion of a, /(-epoxy sulfones 241 with sodium azide in DMF... 

A rather complex microwave-assisted ring-opening of chiral difluorinated epoxy-cyclooctenones has been studied by Percy and coworkers (Scheme 6.131) [265]. The epoxide resisted conventional hydrolysis, but reacted smoothly in basic aqueous media (ammonia or N-methylimidazole) under microwave irradiation at 100 °C for 10 min to afford unique hemiacetals and hemiaminals in good yields. Other nitrogen nucleophiles, such as sodium azide or imidazole, failed to trigger the reaction. The reaction with sodium hydroxide led to much poorer conversion of the starting material. 

The site of attack can also be directed by functionality on the substrate itself, as in the phenyl-boronate-mediated C-2 selective azide ring-opening reaction of trans-2,3-epoxy alcohols (82) by sodium azide. In this reaction, the nucleophile is delivered intramolecularly fiom the azidoboronate intermediate 83. Yields are generally good to excellent <99TL4589>. 

The example in Preparation 2-9 illustrates the general applications of the azide epoxy reaction to large molecules. 

Radiation Chemistry of Phenolic Resin Containing Epoxy and Azide Compounds... 

From this result on MRS, we expected that a combination of phenolic-resin-based resist and aqueous alkaline developer would lead to etching-type dissolution and non-swelling resist patterns. In this paper, we report on a new non-swelling negative electron beam resist consisting of an epoxy novolac, azide compound and phenolic resin matrix (EAP) and discuss the radiation chemistry of this resist. 

Materials. Epoxy novolac, DEN-431, obtained from Dow Chemical Co. was selected as the epoxy component. A 3,3 -diazidodiphenyl sulfone synthesized in our laboratory (5) was used as the azide compound. Poly(/7-vinyl phenol) obtained from Maruzen Oil Co. was used as the phenolic resin matrix. The coating solvent was cyclohexanone. The developer used in this study was 0.1 N tetramethylammonium hydroxide aqueous solution. 

Radiation-induced Reactions in EAP. To elucidate the reason no vacuum curing effect is observed in EAP, we measured the infrared spectra of EAP films under various conditions. The results are summerized in Figures 3 to 5. The infrared spectrum of a standard EAP film is shown in Figure 3. Absorbance at 910 cm-1 (Aep) caused by the epoxy group and that at 2110 cm-1 (Aaz) caused by the azide group were chosen as measures for concentrations of these groups in the films. 

The possible reactions related to vacuum curing termination in the EAP resist are 1 exposure-induced ring-opened epoxy radical with an azide, 2 exposure-induced ring-opened epoxy ion with an azide, 3 exposure-induced... 

Figure 4. Infrared absorbance of epoxy and azide groups in EAP film containing triethlylamine, as a function of baking time (baking temperature ...

These results indicate that vacuum curing occurs through a radical reaction mechanism and is terminated by reaction of the ring-opened epoxy group with the azide group (not nitrene) under exposure. There is a possibility that polymerization initiated by an exposure-induced radical cation may occur. Furthermore, it is thought that reaction products from both the azide and epoxide serve as dissolution inhibitors, because the sensitivity of EAP is almost the same as that of EP, as shown in Figures 1 and 2. 

The result obtained from EAP is shown in Figure 10, where peak 1 represents the azide compound and epoxy novolac dimer, and peaks 2, 3, and 4 represent epoxy novolac trimer, tetramer, and the main component of poly(p-... 

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