D imino

Azetidine-2-carboxylic acid (2) is commercially available. It is readily prepared as the racemate by refluxing 2,4-dibromobutyric acid ester with benzhydrylamine in acetonitrile. If benzyl 2,4-dibromobutyrate is treated with benzhydrylamine, the resulting benzyl TV-benz-hydryl-D,L-azetidine-2-carboxylate is hydrogenolytically processed to D,L-azetidine-2-car-boxylic acid in a one-step reaction. 101,107 Resolution of the racemate can be performed by the method of Vogler 108 via fractional crystallization of the Z-D,L-Aze-OH-H-Tyr-N2H3 salt thereby the salt of the D-imino acid precipitates first from methanol. 96 A stereoselective synthesis of A-tosyl-L-azetidine-2-carboxylic acid can be achieved by a two-step reaction from N-tosyl-L-homoserine lactone. 94 ... 

Metal derivatives of fi-keto imines ( d-imino ketones), synthesis 13... 

This reaction is analogous to the preparation of bis(4-imino-2-pentanonato)copper(II) (bis(4-amino-3-penten-2-onato)copper(II)] described by Holtzclaw, Collman, and Alire, and it consists in mixing an ethanolic solution of the jS-keto imine (d-imino ketone) with an ammoniacal metal salt solution. Advantages of this technique are the simplicity of preparation and the fact that acetylacetone imide (4-imino-2-pentanone) can be purchased. The product is useful as a starting material in ligand-exchange reactions. 

Acetylation of 2-phenyl-4-amino-5-benzoylthiazole takes place on the exocyclic nitrogen (49). This exocyclic nitrogen remains the reactive center even with 2-imino-3-aryl-4-amino-5-carboxamido-4-thiazoline (111). Its acetylation with acetic anhydride gives the 4-acetamido derivative (112), which reacts further on heating to yield 2-(acetylimino)-(3H)-3-aryl-5-methylthiazolo[4,5-d]pvrimidin-7-(6H)-one (113) (Scheme 76) (276). 

Treatment of 2-imino-3-phenyl-4-amino-(5-amido)-4-thiazoline with isocyanates or isothiocyanates yields the expected product (139) resulting from attack of the exocyclic nitrogen on the electrophilic center (276). Since 139 may be acetylated to thiazolo[4,5-d]pyrimidine-7-ones or 7-thiones (140). this reaction provides a route to condensed he erocycles (Scheme 92). 

The synthesis of 9H-benzo[2,l-e]thiazolo-[2,3-c]-as-triazine (401) was achieved by oxydative cyclization of 2-imino-3-(o-aminophenyl)-4-phenyl-4-thiazoline (718, 719). This latter reacts also with paraformaldehyde in hot toluene yielding 3-phenyl-9H.10H-benzo[l,2-/]thiazolo-[2,3-d][l,3,5]triazepine (402) (720). This heterocyclic sytem is also formed when carboxylic acids replace paraformaldehyde (Scheme 230) (721). 

Poly[imino(l,d-dioxo-hexanediyl)imino-hexanediyl]... 

Oxime 26 was prepared from 5,ll-dihydro-dibenzo[a,d]cyclohepten-10-one. The Hoch-Campbell reaction of 26 with 3-dimethylaminopropylmagnesium bromide produced aziridine 27 in 46% yield after acidic workup. Extension of the Hoch-Campbell reaction to steroids has also been reported. Thus, treatment of 3(3-hydroxy-5-pregnen-20-one oxime (28) with methylmagnesium iodide furnished a mixture of diastereomers, 20ot/20P,21-imino-20-methyl-5-pregnen-3P-ol (29) in a 50% combined yield and a 3 1 ratio. On the other hand, homo-adamantan-4-one oxime (30) was transformed to homo-adamantano[4,5-b]-2 -ethylaziridine (31) in 76% yield upon the action of... 

The same amino compounds also underwent reactions with a series of 3-cyano-4-imino- and 3-cyano-4-oxo-piperidines to yield 4-amino-5,0,7,8-tetrahydropyrido[4,3-d]pyrimidines. . A tetra-hydropyTido[4,3-prepared from 4-amino-l-henzyl-3-cyano-d -piperidine (134) hy a simple one-step preparation. This method is of general application for the preparation of fused pyrimidines and previous papers in this field are listed by Taylor. ... 

Phenylcyclopent[c]azcpine (33a) and 6,7-fused cyclopentazepines 33b-d are formed in moderate yields in a one-pot, two-stage process involving initial condensation of triphenyl-[(l-phenylvinyl)imino]phosphoranes 32 with 6-(dimethylamino)fulvene-2-carbaldehyde (30), followed by an intramolecular aza-Wittig reaction of the iminophosphorane with the pendant aldehyde function.5 The method fails with the unsubstituted vinylphosphorane 32 (R1 = R2 = H). 

The latter were further converted in one step to l,4-dideoxy-l,4-imino-D-arabinitol [(2R,3 A,4A)-3,4-dihydroxy-2-(hydroxymethyl (pyrrolidine] and fagomine (l,2,5-trideoxy-l,5-iminohexitol), respectively, by palladium-catalyzed hydration23 27. These compounds are extremely efficient inhibitors of glycosidases24. 

D.1.4. Formation of C —C Bonds by Addition to Imino Groups Houben-Weyl... 

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