Reaction of β-nitrostyrenes with trialkylboranes under nitrogen to generate alkenes in high yields. The mechanism is proposed to be a free-radical reaction via NO2/ alkyl substitution since the reaction is stimulated by the presence of a trace of oxygen in the nitrogen or tert-butyl peroxide or by photolysis and is retarded or inhibited by the addition of galvinoxyl. Reactions of β-nitrostyrenes and triethylborane or tricyclohexylborane in THF solution at room temperature in the air produce trans-alkenes in high yields. Fair good yields of various (E)-alkenes can also be prepared by treatment of β-nitrostyrenes with radicals, prepared from secondary and tertiary alkyl iodides, in the presence of triethyl- borane and air as radical initiator. The generation of the only product (E)-alkenes can be explained by the formation of the benzylic radical as the intermediate. Both (E)- and (Z)- alkenes are formed when (E)- and (Z)-α-alkyl-β-nitrostyrenes react with adamantyl radical under similar conditions. Only (Z)-alkene was observed when either (E)- or (Z)-α-t-butyl-β-nitrostyrene react with adamantyl radical. The Michael addition reactions of β-nitrostyrenes with 4-pentene-1-magnesium bromide or 3-butene-1-magnesium bromide generated nitronates. At room temperature, fair good yields of isoxazoline derivatives were obtained when nitronates were treated with ethyl chloroformate in the presence of catalytic amount of 4-dimethylaminopyridine (DMAP) in one-pot. The ratios of trans and cis-[4.3.0] isoxazoline were from 1:3.00 to 1:4.06 and the ratios of trans and cis-[3.3.0] isoxazoline were >99:1. The formation of [4.3.0] isoxazoline is proposed to proceed via intramolecular nitrile oxide-olefin cycloaddition (INOC).Compounds,obtained from the trapping of the nitrile oxides by ethyl chloroformate could be isolated. The mechanism of the generation [3.3.0] isoxazoline is proposed to proceed via intramolecular alkoxy-carbonyl nitronate-olefin cycloaddtion (IAOC) to form intermediates N-(ethoxycarbonyl)isoxazolidines and then eliminate EtOH and CO2 (or EtOCO2H) to yield the final products. Finally, a series of ring and side-chain regioisomers of arylethylamines are investigated by GC-MS. Regioisomerization at the aromatic ring and the alkyl side-chain in the arylethylamines produces a variety of compounds that have very similar analytical properties. The specific identification of one of these compounds in forensic drug sample depends on the ability to eliminate other regioisomers as possible interfering substances. The mass spectra for the underivatized amines are very similar and do not provide sufficient information to differentiate among the side-chain or ring regioisomers. Preparation the pentafluoropropionyl- amide of the amines produces derivatives that could show mass spectra fragmentation in identifying the position of methoxy groups attached to the aromatic ring and the number of carbons attached directly to the aromatic ring.
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