Oxetane derivatives

A study of the photochemistry of 4-acetyl- and 4-benzoyl-5-methyl-1,2,3-triazoles shows that the nature and lifetime of the lowest triplet state depends on the nature of the 1- and 4-substituents. 4-Benzoyl-5-methyl-1,2,3-triazole has a high rate constant for triplet deactivation, which is attributed to interaction of the nitrogen lone pairs with the excited carbonyl function. The compound forms a pinacol derivative when irradiated in propan-2-ol and undergoes cycloaddition, involving the carbonyl group, with 2-methylpropene, giving an oxetane derivative. 

Richards and Pisker-Trifunac50 have irradiated cw-styrylferrocene (14) under several different sets of conditions and in all cases high conversion to the frans-isomer was the only reaction observed. It is noteworthy that no cyclobutane or oxetane derivatives are formed. The same seems to apply to ferrocenyl analogs of stilbene. That is, no ring formation is observed and the photostationary state consists almost exclusively of the Jrans-isomer. 

Photochemical addition of acetone to cis and trans 1-methoxy-l-butene involves both acetone singlets and triplets.71 Since spin inversion in the 1,4-biradical is relatively slow, predominant loss of stereochemistry is observed in the oxetane derived from triplet acetone. On the other hand, stereochemistry is partially retained when acetone singlets attack the substituted olefin. 

Ethenediyl carbonate (l,3-dioxol-2-one vinylene carbonate, 417) is a readily available,270 versatile synthon having pronounced dienophilic properties.270-275 Diels-Alder adducts of 417 with 1,4-di-acetoxy-1,3-butadiene and furan were selectively converted into cy-clitols,256 257-275 and also served as precursors of DL-ribose derivatives258 (see Section IV, 2). Another possibility of applying 417 as an equivalent of a 1,2-dihydroxyethane unit has been demonstrated in a synthesis of racemic apiose. Photochemical cycloaddition of 417 to 1,3-diace-toxy-2-propanone (418) gave the oxetane derivative 419, which, on alkaline hydrolysis, afforded DL-apiose (420) in 23% yield.1... 

The biological properties of oxetanes are slowly attracting attention, although many have been known for a long time. For example, 2,2-bis(p-ethoxyphenyl)-3,3-dimethyloxetane is an excellent insecticide, 25 times as potent as DDT (71MI51300). Many oxetanes have been patented as fungicides. The recent discovery of thromboxane A2 and the antileukemic toxanes will undoubtedly stimulate further study of oxetane derivatives for possible medical and biological applications. 

Ditrifluoromethyl oxetane derivatives, ( ), prepared by Sumida Lindsey et al. 

Photochemical isomerizations by intramolecular 4n + An cycloaddition of carbon oxygen linked bichromophoric anthracenes to give oxetane derivatives have not been reported yet. Upon irradiation (X > 400 nm) in either toluene or ethyl acetate, the methoxycarbonyl substituted carbon oxygen linked bichromophoric anthracene 14 indeed isomerizes smoothly and efficiently (cp — 0.45). However, the two products, obtained in an approximate ratio of 5 1, are anthrone derivatives 15 and 16 whose formation can be rationalized by migration of the anthryloxy moiety [60], An analogous photolytic rearrangement has been found for 9-anthryloxy substituted dianthrylethylenes (see Section III.A). 

Scheme 7.8 Regioselective formation of oxetanes derived from furans or vinyl ethers the nucleophilicity rule.

The irradiation of methyl phenylglyoxylate, benzil, benzophenone as well as 1,4-benzoquinone in the presence of homobenzvalene 103 gave, as products of the Paterno-Buchi reaction, oxetane derivatives which contain the tricyclo[4.1.0.02,7] heptane subunit as well as ring-opened products (Sch. 31) [100]. 

Mass spectral data have been reported for an oxetane derivative of (1) formed by the reaction of benzophenone with l-acetyl-pyrrolo[2,3-6]pyridine (Scheme 1). The major fragments upon electron impact result from a retro-Diels-Alder process to give the original component ions. These ions then undergo further fragmentation <76JHC585>. 

The synthesis of fused oxetane derivatives via the Paterno-Bchi cycloaddition of carbonyls and alkenes is discussed in detail in a representative example is shown in Scheme 7 <2001CEJ4512>. See also Sections 3.3.1.8.3 and 3.4.1.10.5 for the preparation of fused oxetanes and azetdines by [2 + 2] cycloaddition reactions. Benzox-etan-2-one 10 has been prepared in an argon matrix by C02 loss from phthaloyl peroxide <1973JA4061>. 

Patent Fluorinated Oxetane Derivatives and Production Process Thereof... 

A single step method for preparing other Step 4 perfluoroalkoxy-oxetane derivatives is illustrated in Fq. 1 and discussed (1). 

The preparation of mono- and di-adamantyl 1,2-oxetane derivatives used as stable chemiluminescent agents is described (3). 

Oxetanes. The sodium anion (Z) of this sulfoximine reacts with ketones to form epoxides (3) in good yield. Welch and Prakasa Rao now report that in the reaction of ketones with an excess of 2 at elevated temperatures intermediate epoxides undergo ring expansion, with formation of the corresponding oxetane derivative. 

G-Metbanesulfoncxy-l,2-iwpropyiideQe-D-xyloae reacted with ajeo-holic potassium hydroxide to give the oxetane derivative (XXXlV) in S5% yield,ii the same result being obtained with the corresponding toeylate.> ... 

The reaction seen in Eq. 305 results in oxetane derivatives by means of neighboring-group participation (Eq. 305). ... 

A similar rearrangement and geometric isomerization occur in the case of 2,4-hexadienemonooxirane. Irradiation of the spirooxirane 135 leads to cumulene, 135a, allyl alcohol 135b, and oxetane derivatives 135c. ° Cumulene formation is interpreted as occurring via a cyclopropylcarbene. 

R and R may be H, methyl, cyclopropyl, cyano, or ester groups. The phenylcarbene formed on irradiation of trans-l,2-diphenyloxirane has been trapped and identified in the form of a cyclopropane derivative in methanol in the presence of benzyl methyl ether and alkenes. Photolysis in the presence of 2,3-dimethyl-2-butene proceeds by cycloaddition with the formation of cyclopropane-carboxylic acid and oxetane derivatives (Eq. 368). ... 

There are various procedures for the preparation of polyethers. These procedures typically start with oxirane or oxirane derivatives (e.g. propylene oxide, etc.). Base catalyzed anionic polymerization, acid initiation, or complex coordination catalysis can be used for the reaction [1-3], Not only oxiranes can generate polyethers. Diols also can be used for polyether synthesis. Other source compounds include tetrahydrofuran, which can be polymerized to a polyether using fluorosulfonic acid (HSO3F) as a catalyst, oxetane (trimethylene oxide) or oxetane derivatives, which can be polymerized to generate polyethers with practical applications such as poly[bis(chloromethyl)oxetane], etc. 

Vargas, F., Rivas, C. Photochemical formation of oxetanes derived from aromatic ketones and substituted thiophenes and selenophenes. InternationalJournal of Photoenergy 2000, 2, 97-101. 

Chemical transformations of nucleosides have resulted in the syntheses of some 2, 3 -unsaturated pyrimidine nucleosides as well as a 4, 5 -unsaturated pyrimidine nucleoside. Treatment of 3 -O-tosyl-2 -deoxy-adenosine with alkoxide produced the 2, 3 -unsaturated nucleoside as well as a smaller amount of the 3, 5 -oxetane derivative. The syntheses of 2, 3 -dideoxy-, 2, 5 -dideoxy-, and 2, 3, 5 -trideoxyadenosine have been accomplished by mono- or ditosylation of 2 -deoxyadenosine... 

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