Benzoyl aziridinization

The same regiochemistry is observed when nitroimidazole (48-2, 48-3) acts as a nucleophile in unionized form. Thus, the reaction of a compound with benzoyl-aziridine (49-1) in the presence of boron trifluoride probably involves an initial salt formation with an amide attack by the imidazole results in a ring opening and the formation of the alkylated product (49-2) the free primary amine (49-3) is obtained on basic hydrolysis. Acylation of the primary amine with methyl thiochloroformate gives the corresponding thiourethane, carnidazole (49-4) [52]. 

A similar sequence was performed by using ethoxycarbonyl azide to prepare the A-unsubstitut-ed and the A-benzoyl aziridine 17. From the latter, the dihydrooxazole precursor 18 of the cis-hydroxyamine was quantitatively obtained53. 

The reaction of (271 R = H, R = H or Me) with ethyl propynoate proceeded via Michael addition, to form (271 R = CH=CHC02Et), and subsequent rearrangement to the dihydronaphthalene (272). " 2-Benzoyl-aziridine (273) and RCH2C02Et (R = H or Ph) react in the presence of NaH to provide a novel synthesis of pyridinones (275). " The original objective of this study was the synthesis of the azabicyclo[3.1. Ojhexane (274), which was formed as an intermediate but not isolated from the reaction. 

A.L. Gardoso, R.M.D. Nunes, L.G. Arnaut, T.M.V.D. Pinho e Melo, Synthesis of pyrroles in supercritical carbon dioxide formal [3 + 2] cycloaddition of 2-benzoyl-aziridines and aUenoates, Synthesis (2011) 3516-3522. 

Aziridine, trnns-2-benzoyl-1 -cyclohexyl-3-phenyl-UV, 7, 50 <663001244, 753A2822)... 

Aziridine, 3-benzoyl-trans-A/-benzyl-2-phenyl-irradiation, 7, 62... 

Aziridine, 3-benzoyl-1 -t-butyl-2-phenyl-photochemistry, 7, 62 Aziridine, 2-t-butyl- N NMR, 7, 11... 

A 3-acetoxypropyl group was used to protect an aziridine — NH group during the synthesis of mitomycins A and C acetyl, benzoyl, ethoxycarbonyl, and methoxymethyl groups were unsatisfactory. ... 

Treatment of aziridine 137 (Scheme 3.64) with benzoyl chloride in the presence of pyridine and DMAP afforded ring-expansion product 179 in 90% yield [45], The reaction was believed to proceed through the intermediate N-acylaziridine 178. 

Ammonium perchlorate, Impurities, 4004 Azidoacetic acid, 0774 f Aziridine, Acids, 0863 Benzoyl azide, 2698 Benzyl chloroformate, 2931 1,2-Bis(dilluoroamino)-A-nitroethylamine, 0803 Bromine trioxide, 0259 2-Butanone oxime, 1654 2-Butyne-l,4-diol, 1526... 

Highly substituted chalcones and one equivalent of NH2OH afforded substituted trans-2-benzoyl-3-phenyl-1H-aziridines . ... 

A -acylaziridines substituted with an electron-withdrawing group produce a 2,4-disubstituted oxazoline as the major product. Borontrifluoride etherate (BF3 OEt2) has also been used successfully for an Al-benzoyl, but not an N-acetyl-substituted aziridine (Scheme 8.58). ... 

The reaction of 2 -benzyloxychalcone dibromides (605) with ammonia gives a chalcone aziridine (606). Following conversion to the (V-benzoyl derivative, acid hydrolysis removed the protecting group at C-2 and a 3-aminoflavanone results (Scheme 230) (73ACH(76>95). 

Anilinocarbonyl-3-bcnzoyl(or 4-fluoro-benzoyl)-2-(4-fluoro-phenyl)(or phenyl)- E16c. 577 (2-Aroyl — 3-Ar — aziridin +... 

Benzoyl-1-methyl-3-phenyl-5-trifluoromethyl- ElOb,. 550/551 (En-Ar + F3C-aziridine) 1-Benzyl-4-ethoxycarbonyl-.3-phenyl-3-trifluoromethyl- ElOb, 547 (KjC-en-COOR t RO-CH,-NR-CH,-SiR3) 1-Bcti7yl-4-cthoxycarbonyl-3-trifluoromcthyl- ElOb,. 547 (F,C-en-COR + RO-CH3-NR CH2 SiR3)... 

Padwa and Hamilton examined other aziridines where the nitrogen was unsubstituted.43 44 cis-1,2-Diphenylaziridine (21) on refluxing with DMAD in benzene gave 85% of the adduct 22 DEAD was also used. tranj-2-Benzoyl-3-phenylaziridine (23) gave the pyrrole 24 with DMAD the latter was also synthesized from 4-benzyl-2-phenyl-5-oxazolone (26), via 25, which was oxidized with selenium dioxide to 24. 

The 5-benzoyl triazoline (Scheme 76) upon heating gives aziridine although it enters into competition with the retroaddition reaction, forming the starting azide and olefin.292... 

Lewis acid]+[Co(CO)4] complexes have been reported as a versatile class of catalysts for carbonylative ring expansion of aziridines to p-lactams [147]. For instance, catalysts such as [C5H5Ti(thf)2][Co(CO)4] and [(salph)Al(thf)2][Co (CO)4]1 [148] have been shown to efficiently carbonylate a variety of aziridines under mild conditions. Further, the authors proposed a mechanism for the CO insertion into aziridines. A theoretical investigation has been also reported for the [Co(CO)4] -catalyzed carbonylative ring expansion of (V-benzoyl-2-methylaziri-dine to p-lactams (Scheme 58), [149]. 

An example of azaheterocycle synthesis based upon aziridinyl ketones is also a reductive cyclization of l-cyclohexyl-2-benzoyl-3-(2-nitrophenyl)aziridine 68 into quinoline 69 [14] (Scheme 1.18). 

Regiospecific 1,3-dipolar cycloaddition reactions of dihydropyridines and some organic azides lead to high yields of fused aziridines—2,7-diazabicy-cli[4.1.0]hept-3-enes 337 [365, 366, 367] (Scheme 3.112). The reaction proceeds via the preliminary formation of an intermediate 336 and the elimination of nitrogen. Reaction of pyrimidine 334 with less reactive methoxycarbonyl and benzoyl azides does not occur [367]. Compounds 337 exhibit significant analgesic, antibacterial and antifungal activities [367]. 

Azirines react with carboxylic acid chlorides in benzene to give the Ar-benzoyl-2-chloroaziridines (133) in good yield.23,60 These aziridines are unstable and are converted in polar solvents or by heating into a mixture of the oxazole and dichloroamide (134). 

Aggarwal and Vasse have applied asymmetric ylide aziridination to the synthesis of the taxol side chain 26 [75]. By using stoichiometric quantities of chiral sulfide, 26 was obtained in six steps and 16% overall yield (see Scheme 10.19, route A), while the catalytic variant allowed access to 26 in seven steps and 20% overall yield (see Scheme 10.19, route B). Both methods gave the key aziridine intermediates in excellent enantiomeric purity. Unfortunately, the benzoyl imine 25 did not work well in the catalytic reaction, and so a slightly longer synthetic route... 

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