1-Benzyl aziridine

Die durch 4-Methyl-benzolsulfonsaure katalysierte Tetramerisierungvon 1-Benzyl-aziridin ergibt in hoher Ausbeute ein Kronenamin, 1,4,7,10-Tetrahenzyl-1,4,7,10-tetraaza-cyclo-... 

Figure 1. Determination of f k,A<, according to Equation 4, for the polymerization of 1-benzyl aziridine 1 2-cyano-ethyl)aziridine (O), and l- 2-phenyletlwl)aziridine ( ) in CHy Clt at 0°C uHth triethyloxonium tetrafluoroborate as initiator, mo = 1.0 mol r ...

The different behaviour as far as termination is concerned between the aziridine monomers and their 2-methyl analogues is also well illustrated by the observation that a polymerized solution of 1-benzy1-2-methyl aziridine (BMA) is capable of initiating the polymerization of 1-benzyl aziridine (BA) but the reverse is not possible. This again proves that the former polymer (if not too old) still contains active chain-ends capable to initiate the polymerization of BA, whereas poly-BA is "dead" directly after the polymerization. 

Diphenyl-4,5-dihydro-l,2-oxazol —> cis-3-Phcnyl-2-benzyl-aziridin 31% d.Th. 

In the reaction of fused aziridines with alkene dipolarophiles, the opportunity for stereoselectivity as well as facial selectivity arises since exo- or entfo-isomers can be formed (Scheme 10). In practice, maleic anhydride 6, A-methyl maleimide and JV-phenyl maleimide each reacted exo-stereoselectively with TV-benzyl aziridine 69 to form adducts of type 71 (Scheme 10b), the stereochemistries of which were confirmed by NOE measurement between Hb and He. Similar reaction of the Y-phenyl aziridine 67 with N-Ph maleimide gave a 1 1 mixture of endo-adduct 72 and exo-adduct 73 (Scheme 10c). Adducts 68, 71-73 all exhibited a low-field methano-bridge proton (Ha) in the range 5 3.06-3.60 confirming the syn-facial stereochemistry of the two bridges. 

Reaction of norbomadiene 74 (in excess) with 7V-benzyl aziridine 67 formed exclusively the all-sy l l-adduct 77. This stereochemistry, confirmed by NOE between Ha and Hb, resulted from attack at the underface of the dipole by the exo-face of the dipolarophile. Similarly, reaction of A -benzyl aziridine 67 with the diacetoxybenzonorbomadiene 30 gave a single adduct 78 (Scheme 11), the symmetrical structure of which was clearly apparent in the ll NMR spectrum. These stereochemical outcomes demonstrated that the transition state (TSa), in which the methano-bridge was adjacent to the (V-substituent, was favoured in the A -benzyl series (X and R small), and in accord with the semiempirical calculations. 

Whereas A -benzyl aziridine 69 reacted with the methano-bridged dipolarophile 39 to give exclusively TSA-product 79, use of the bulkier isopropylidene bridged dipolarophile 38 afforded substantial amounts of the TSB-adduct 84 as well as some of the TSA-product 80, an outcome attributed to unfavourable X)(NR TSa interaction in the latter reaction (X large, R small) (Scheme 12a). 

The JV-benzyl aziridines 69, 92-95 which differ only in the nature of the norbomane bridge (CH2, spirocyclopropyl, isopropylidene, oxygen, substituted nitrogen) (Scheme 14), have been prepared and reacted with each of the corresponding benzonorbomadienes 36-40 from which they were derived. All 25 reactions were conducted to produce 14 of the possible 15 different... 

N-Benzyl aziridine was also oligomerized by the author and others (2) by acid catalysis as summarized below ... 

Aziridines react with nucleophiles other than carbon nucleophiles. In the presence of TBAF, trimethylsilyl azide react with V-tosylaziridines to give the azido A-tosylamine. A-Benzylic aziridines are opened by trimethylsilyl azide in the presence of a chromium catalyst. Acetic anhydride reacts with N-tosylaziridines, in the presence of PBU3, to give the A-tosylamino acetate. A-Tosylaziridines react with InCls to give the chloro A-tosylamine. ... 

The more crown-like tetra-aza-molecule (447), which had previously been prepared by the action of acid on N benzyl aziridine, is now reported as the product of an anodic oxidation. The mechanism postulated proceeds via a ring-opened radical cation (446), which polymerizes, cyclizes, and then initiates another sequence. 

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

Treatment of aziridine-2-carboxylic ester 251 (Scheme 3.93) with benzyl mercaptan in the presence of boron trifluoride etherate afforded 252 in 71% yield [142]. Compound 252 has been transformed into peptide 253, an analogue of a penicillin precursor. 

This conversion has been used as a key step in the preparation of optically active aziridines from optically active 1,2-diols (prepared by 15-46). ° Even hydrogen can be the leaving group. Benzylic hydrogens have been replaced by N3 by treatment with HN3 in CHCI3 in the presence of DDQ (p. 1511). °°... 

Iron phthalocyanine is an efficient catalyst for intermolecular amination of saturated C-H bonds. With 1 mol% iron phthalocyanine and 1.5 equiv. PhlNTs, amination of benzylic, tertiary, and ally lie C-H bond have been achieved in good yields (Scheme 31). With cyclohexene as substrate, the allylic C-H bond amination product was obtained in 75% yield, and the aziridination product was found in minor amount (17% yield) [79]. 

Very reactive nitrogen mustards and aziridine-containing molecules are usually too toxic for general therapeutic use, but find use in neoplastic disease. Benzodepa (182) is such an agent. Treatment of ethyl carbamate with phosphorous pentachloride leads to cyanate 180 which readily adds benzyl alcohol to produce carbamate 181. Displacement of the active... 

Researchers have found that the reduction of a variety of aziridine esters yields the corresponding aziridine aldehyde which dimerizes diastereoselectively <06JA14772>. The reduction of 112 with excess DIBAL yields the dimer 113, which is in equilibrium with the monomer 114. This molecule reacts as the monomer and both reduction to 115 or reductive amination to 117 proceed in quantitative yields. In a very interesting reaction, treatment of 113 with /V-benzyl tryptamine provides the pentacyclic 116 in excellent yield. 

Reaction of A,A-dimcthylsullamoyl aziridines 323 and 325 with primary amines furnishes substituted 1,2,5-thiadiazolidine 1,1-dioxides 324 and 326, respectively, in a regioselective manner <06SL833>. Aziridine 325 is made from ( I /t,6,S ,Z)-bicyclo[4.2. l]non-3-en-9-one in two steps /V,/V-dimethylsulfamoyl imine formation using dimethylsulfamide and subsequent reaction with trimethylsulfoxonium ylide. The product from the reaction with 4-methoxy-benzyl amine can be subsequently manipulated (debenzylation and derivatization) to give the alternative nitrogen substitution pattern in a controlled manner. 

In molecules containing two cyclobutenes, addition of organic azides 26 yielded two adducts, e.g. reaction with 50 with benzyl azide 56 produced the cr-isomer 57a in which the (V-benzyl substituents were sy -aligned and the C2-isomer 57b in which they were anti-orientated (Scheme 7). The structure of syn-isomer 57a was confirmed by X-ray (Figure 2). The fact that both isomers yielded the same fns-aziridine 58 upon photolysis made separation of the individual triazoline isomers unnecessary. 

Transition state energies have been determined by computation (PM3 and AMI) for the reaction of norbomadiene 74a (X=CH2) and 7-isopropylidenenorbomadiene 74b (X is C=CMe2) with the 1,3 dipoles 23 formed from ring-opening of the A -phenyl and A -benzyl derivatives of aziridine 22 (see, Table 1). These data demonstrate the preference for formation of exo,exo-isomers 75 with norbomadiene in the A -benzyl series, however the energy difference between the transition states for the A -phenyl series is much closer and accords with the drop in stereoselectivity. Introduction of the isopropylidene substituent into the 7-position of the dipolarophile favours formation of the bent-frame isomers 76, especially in the A -phenyl series. These predictions accord well with the stereoselectivities observed experimentally. 

Tanner et al. (58) investigated the use of chelating diaziridines (85) as ligands for transition metals. The cyclopropanation of styrene using CuOTf complexes of phenyl-substituted aziridine (85a) proceeds in modest enantioselectivity and dias-tereoselectivity, but improved enantioselectivity is observed with complexes derived from benzyl-substituted bis(aziridine) (85b), Eq. 42 (59). Complexes derived... 

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