3- Methyl-4-nitro-5-styrylisoxazoles

The photodimerization of 3-methyl-4-nitro-5-styrylisoxazoles 137 has been studied in the solid state82. Truxillic acids 139 are prepared by the oxidation of the photodimers 138 (equation 69). 

The data on UV-spectroscopy of nitroisoxazoles are rather scarce. It is known that X for 3,5-dimethylisoxazole is 215-220 ran, whereas that for its 4-nitroderivative lies in a field of 250-270 nm depending on the medium (see Table 3.65) [483,499, 1125, 1159], It is shown [483] that for 5-(p-methoxystyryl)- and 5-cinnamylidene derivatives of 3-methyl-4-nitroisoxazole, the absorption band is moved to the longwave area (290 nm, lg e 4.15). The absorption band maxima of 3-methyl-4-nitro-5--styrylisoxazole photodimers lie in field of 268-272 nm. In works of the Italian authors the electron absorption spectra of some derivatives of nitroisoxazole are described [1160],... 

Diethylphosphonomethyl-3-methylisoxazole was alkylated and olefinated by reaction of its anion with alkyl halides and aldehydes <1999S2027>. Reactions of 3-methyl-4-nitro-5-styrylisoxazole with bis-enolizable ketones have been investigated. Michael adducts were obtained in good yields with substoichiometric amounts of base while spiroisoxazolines were the major products when the base was employed in large excess <2002TL4157>. 

Racemic Michael addition of 5-nucleophiles, such as PhCH2SH, to 3-methyl-4-nitro-5-styrylisoxazoles (240) can be effectively catalysed by piperidine (10mol%) in MeCN. Nitroisoxazoles (240) also undergo regio- and diastereo-selective trifluo-romethylations at the 5-position by nucleophilic addition using Me3SiCF3. ... 

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