Nitrogen alkylation

An interesting intermediate 30 was proposed to result from the sequential addition of pyridine to tetrachlorocyclopropene (31). Compound 30 represents an alkyl nitrogen ylide with two 1-chloroalkyl pyridinium moieties in the same molecule. Pyridines with electron-withdrawing groups and heterocycles with an electron-deficient nitrogen, for example, pyridine-3-carbaldehyde or quinoline, react with 31 to yield the corresponding mono-substituted products 32a and 32b (83JOC2629) (Scheme 8). 

II. CORRELATIONS OF ENTHALPIES OF FORMATION OF ALKYL NITROGEN-CONTAINING COMPOUNDS... 

Asano N, Kizu H, Oseki K, Tomioka E, Matsui K, Okamoto M, Baba M. (1995) A-Alkylated nitrogen-in-the-ring sugars Conformational basis of inhibition of glycosidases and HIV-1 rephcation. JMed Chem 38 2349-2356. 

Both nitrogen chemical shifts and coupling constants (JNH. Jnc) were used to locate the alkylated nitrogen. All the 15N-labeled thiatriazoles were prepared as outlined in Scheme 1. For a detailed discussion, the reader is referred to the original paper.6... 

The ligand field of the macrocycle is also modified by ring distortion.154 The metal to alkylated nitrogen distance is 2.33 A (Fe) to 2.53 A (Zn) which is considerably longer than the normal value of 2.0-2.1 A for the first row transition metalloporphyrins in a high spin state, while the extension is small for the other three M—Npor bonds. The reduced and distorted ligand field of the macrocycle makes it possible for even the Co complexes as well as other metals to take a high spin state. 

NMR spectra of some alkyl nitrogen difluorides have recently been reported. Their characteristic spectra are given in Scheme 7.6. Note the huge (560 Hz) two-bond F-F coupling through nitrogen that is reported... 

There is not room here to discuss the detailed mechanisms by which exposure to radiation causes adverse responses. Much of the effects of radiation result from its interaction with water to produce active species that include superoxide (Oi), hydroxyl radical (HO-), hydroperoxyl radical (HOO), and hydrogen peroxide (H202). These species oxidize cellular macromolecules. When DNA is so affected, mutagenesis and carcinogenesis may result. Ionizing radiation can also interact with organic substances to produce a carbonium ion, such as +CH3, that can alkylate nitrogenous bases on DNA. 

The isomers of Cr(men)3 isomerize with half-lives (several hours) similar to the Cr(benz)3 complex. The rate of isomerization of the tris-(hydroxamate) complexes is therefore not particularly sensitive to the substituent of the hydroxamate nitrogen atom, since the men ligand contains an alkylated nitrogen atom, and the benz ligand contains an unsubstituted nitrogen atom. In the absence of an induced strain, the corresponding siderophore complexes must isomerize much more slowly because of the steric constraints of the ligand. 

Rearrangement alkylation of cycloalkylhydroxylamine carbonates.9 These hydroxy lamines, which can be prepared from cycloalkyl amines or cyclic ketones, on reaction with a trialkylaluminum rearrange to an a-alkylated nitrogen-containing heterocycle. The complete sequence is formulated for synthesis of an a-alkylated piperidine (equation I). 

As to alkylammonium IPRs, it is clear that the retention enhancement of oppositely charged analytes increases with increasing numbers of alkyl nitrogen substituents monoalkylammonium < dialkylammonium < trialkylammonium < tetraalkylammo-nium. Again, the longer the alkyl chain, the more effective the IPR [12],... 

Cyclophosphamide is an alkylating nitrogen mustard derivative mainly used in oncology patients (1) or in conditioning regimens for bone marrow transplantation. Its immunosuppressant properties have been used in organ transplantation and more often in chronic inflammatory disorders or autoimmune diseases. 

Alkylation The addition of an alkyl group, to a carbon (C-alkylation), nitrogen (/V-alkylation), oxygen (O-alkylation), or sulphur (//-alkylation) atom. 

Two types of alterations of the quaternary head have been studied replacement of the nitrogen by other atoms and replacement of the N-methyl groups by hydrogen, alkyl, nitrogen, or oxygen. Acetyl phosphonocholine (5) (39), acetylarsenocholine (6) (39), and ace-... 

With the appropriate indole substrate 83 now in hand, attention of the Dolby group turned to installation of the ethylene bridge between the alkyl nitrogen and the indole 3-position to construct the desired quaternary center contained in the core of akuamnuline alkaloids. Toward this end, chlor-oacetamide 217 obtained via treatment of the indole 83 with chloroacetyl chloride, was subjected to sodium hydride in DME at room temperature (Scheme 25). No product of cyclization was seen under these conditions. Amine 83 was also treated with ethylene oxide to provide aminoethanol 219 this alcohol was then activated as a sulfonyl ester. Efforts to affect cyclization in this manner also proved unsuccessful. 

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