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The oxoiminium salts 4a, b, and 8 obtained by alkylation with Et3OBF4 of the aldonitrones 3a, b, and 7 react with diphenyl hydrogen phosphite to give the N-alkoxy α-amino phosphonic esters 6 and 9a, b. Similarly, the cyclic imine oxides 10a, b and the cyclic oxime ethers 14a, b afford the α-branched N-alkoxy α-amino phosphonic esters 12a, b and 16a, b, respectively. Hydrogenolysis and ester hydrolysis affords the α-methyl α-amino phosphonic acid hydrochlorides 13a, b and 17a, b.

For synthetic purposes, the polyether-based secondary alcohols 7 and 8 were prepared from acetone O-methyloxime (1). This applies the (Z) effect for the geometry-directed alkylation sequence, recovery of the keto group and reduction. In contrast to 11, α-phenylthio-substituted O-alkyloxime 26 was found to be unsuitable as starting material for such synthesis. The strong effect of bivalent sulfur in the α-position shadows the (Z) effect and permits only lithiation next to the sulfur atom.

The synthesis of optically pure chloromethyl (―)-menthyl ether (2b) and its use in the synthesis of di- (―)-menthyl acetal (―)-menthyl (+)-menthyl acetals are described. The diastereomeric mixed acetals 7a, b and 8a, b are easily obtainable from the nitrones 5 and 6, KCN and 2b. The mixtures of diastereomers are separated into the pure components 7a, 7b and 8a, 8b by simple silica gel column chromatography. Hydrolysis of these products (H 2 O 2 /Na 2 CO 3 , ultrasound) followed by N-O cleavage affords the heterocyclic α-methyl-α-amino amides 11a, 11b and 12a, 12b. These are subsequently hydrolyzed to give the corresponding α-methyl-α-amino acids with S and R configuration, respectively

Reaction of the dilithium salts of the dioxime diethers 1 gives the polyoxime-based macrocyclic systems 2–4. Temperature and lithium effects indicate that mixed aggregates play an important role in the formation of these heterocyclic systems by oxidative coupling. An X-ray structure analysis of 3f has been carried out showing that the thermodynamically unfavored Z configuration is a characteristic feature of this reaction product.

Lithiation of 5,6-dihydro-3-methyl-4H-1,2-oxazine (4) in an unpolar solvent system (hexane/THF) at −65°C followed by reaction with Cl2,Br2, or I2 affords cleanly and stereoselectively 6 (RS,RS) of which an X-ray structure analysis is described. In contrast, attempts to couple the halogenated 1,2-oxazine derivative 5c have given, under various reaction conditions, equal amouts of 6 and 8 (meso). A mechanism of this reaction is discussed.

Oxime ethers 1 react with ammonia and primary amines to give α-amino oxime ethers. The reaction of α-bromo oxime ethers with sodium azide affords α-azido oxime ethers. Hydrogenolysis of the azido compounds using 5% palladium on calcium carbonate as catalyst yields the α-amino oxime ethers. The reaction of α-azido oxime ethers with lithium aluminum hydride gives 1,2-ethanediamine derivatives. The reaction of azido oxime ether 13 with LiAlH4, and subsequently the reaction of the resulting mixture of the diamines 14 and 15 with phosgene, preferably gives cis-4-pentyl-5-methyl-2-imidazolidone (16) indicating that the reduction of 13 proceeds in a stereoselective manner to furnish mainly the syn-1,2-ethanediamine 15.

Reaction of the lithium salts of oxime ethers 4a–c with methanesulfonyl azide gives the α-diazo oxime ethers 5a–c. These novel compounds are stable up to 90°C, however, they decompose thermally in refluxing CCl4 and with PdCl2 catalysis to yield the ethylene diketone bis(O-methoxyloxime) derivatives 6a–c in yields of 85–91%. The preparation and characteristic spectral features of 5a–c are described.

The reaction of alkyl hydroxamates 2 with (C2H5)3O · BF4 in CH2Cl2 affords N-alkoxyimidates 3. The direct alkylation of hydroxamic acids 1 with 1,2-dibromoethane gives the 5,6-dihydro-1,4,2-dioxazine derivatives 4. The reactions of the acyclic imidates 3 as well as the cyclic N-alkoxyimidates 4 with N-bromosuccinimide in CCl4 produces the α-bromoimidates 5a–d and 6a–d. The α-bromine atom in the bromides 5b, d and 6a, b, d can be displaced by fluorine and azido substituents to yield the α-fluoro-N-alkoxyimidates 7b, d and 10a, b, d and the α-azido compounds 8b, d and 11a, b, d, respectively. The reduction of the azides 8b, d and 11a, b, d affords the α-aminoimidates 9b, d and 12ab, d, respectively. The reaction of the bromides 6a–d with benzene derivatives 14a–d in the presence of AgBF4 affords the aromatic substitution products 15a–d. Acid-catalyzed hydrolysis of 15a, c gives the arylsubstituted carboxylic acids 16 and 17.

The diselenacyclodecane ring in the title compound, C 12 H 20 N 4 O 4 Se 2 , adopts a twist-twist-boat conformation with regular trans positions of the oxime groups. In this conformation, the intramolecular spatial interaction of the oxime fragments decreases to a minimum. This molecule is an E,E,E,E isomer with regard to the configuration of the oxime groups

The synthesis of 2-(Aminophenyl)-2-hydroxyethylphosphonates rac-4a-c is based on the formation of a hydroxyl function via addition of the lithium salt of dimethyl methylphosphonate (2) to aldehydes 1a-c. The amino function in rac- 4a-c is obtained by catalytic reduction of the nitro group in 3 at low pressure. The incorporation of the aminophosphonates rac-4a-c in short peptides, enables the formation of potential bioactive materials 12–14.

The synthesis of dimethyl 2-acetoxy-2-(2,4-diiodo-5-aminophenyl)ethylphosphonate and dimethyl 2-acetoxy-2-(2,4,6-triiodo-3,5-diaminophenyl)ethylphosphonate is described. Several amido and peptidic derivatives of these two compounds were prepared. These products are composed of a combination of structural/functional moieties which pave the way for their potential application as non-ionic selective X-ray contrast agents.

Regiocontrolled deprotonation (e.g. lithiation) of 3-methyl-4-H-5,6-dihydro-1,2-oxazine 1 is achieved at −65°C. The lithiated compound reacts cleanly with the halogens Cl2, Br2 and I2 at low temperatures (−65°C) to give the corresponding 4-halo derivatives. Reaction of the 4-iodo compound 2a with KF in diethyleneglycol gives the elimination product 4 whereas the bromo compound 2b reacts under substitution to the 4-fluoro derivatives 5. The fluorooxazine derivatives 8a-c were converted to the αfluoroenones 11 a-c via the oxoiminium salts 10a-c. The U.V. and 1HNMR of the novel series of halides 2a-c and 5 were studied.