Branched chains amines

Inhalation of aerosols or heated vapors may result in irritation of the nose, throat, and upper respiratory system. Lower molecular weight and branched-chain amines are more volatile and can cause irritation if inhaled. Volatile amines are easily recognized by their unpleasant, fishy odor. 

Thiuram Sulfides. These compounds, (8) and (9), are an important class of accelerator. Thiurams are produced by the oxidation of sodium dithiocarbamates. The di- and polysulfides can donate one or more atoms of sulfur from their molecular stmcture for vulcanization. The use of these compounds at relatively high levels with litde or no elemental sulfur provides articles with improved heat resistance. The short-chain (methyl and ethyl) thiurams and dithiocarbamates ate priced 2/kg. Producers have introduced ultra-accelerators based on longer-chain and branched-chain amines that are less volatile and less toxic. This development is also motivated by a desire to rninirnize airborne nitrosamines. 

For the most part, the corrosion protection potential of filmers improves with increased packing of amines onto the metal surface, so straight-chain-only amines are preferred (no side chains or branched-chain amines) for formulation purposes. 

Boron enolates can be obtained from esters40,41 and amides42 by methods that are similar to those used for ketones. Various combinations of borylating reagents and amines have been used and the E.Z ratios are dependent on the reagents and conditions. In most cases esters give Z-enolates, which lead to syn adducts, but there are exceptions. Use of branched-chain alcohols increases the amount of anti enolate, and with t-butyl esters the product ratio is higher than 97 3. 

Thus, treatment of 11 with paraformaldehyde and TBAF in THF provided the novel branched-chain nitro sugar 54. Reduction of its nitro group to the amino group of 55 followed by deprotection of its anomeric position, resulted in the amine 56, that finally led to compound 57, the first reported branched-chain seven-membered imino sugar, after a synthetic sequence consisting of a reductive amination. 

The phosphate method has not been synthetically useful for alkylation of anilines of low basicity such as -nitro- or p-trifluoroaniline. Only monoalkylation occurs in introducing branched-chain alkyl groups such as isopropyl. Use of this method for alkylation of aliphatic amines has not been reported. 

Figure 8.17 The metabolism of branched-chain amino acids in muscle and the fate of the nitrogen and oxoacids. The a-NH2 group is transferred to form glutamate which is then aminated to form glutamine. The ammonia required for aminab on arises from glutamate via glutamate dehydrogenase, but originally from the transamination of the branded chain amino acids. Hence, they provide both nitrogen atoms for glutamine formation.

Four types of organic amines exist, as shown in Table 4.8 primary amines RNHj, secondary R2NH2, tertiary RsNH, and quaternary R4N (Appendix D). The hydrocarbon chain R is usually of length Cg-Cu, commonly a straight aliphatic chain, but branched chains and aromatic parts also occur. In general the amines extract metal complexes in the order tertiary > secondary > primary. Only long-chain tertiary and—to a smaller extent—quarternary amines are used in industrial extraction, because of their suitable physical properties trioctylam-ine (TOA, 8 carbons per chain) and trilauryl amine (TLA, 12 carbons per chain) are the most frequently used. For simplicity we abbreviate all amines by RN, and their salts by RNH L . 

Small-pore zeolites can accommodate linear chain molecules, such as straightchain hydrocarbons and primary alcohols and amines, but not branched chain molecules. As discussed in the previous section, the port size can be enlarged to about 500 pm in diameter by replacing sodium ions with calcium ions. 

Si-Si coupling and Si-X functionalization had to be modified and extended. The preparation of CH3Si[Si(CH3)3]3 is based on the procedure reported by Marsmann et al.6 The functionalization of the branched-chain silane occurs by the method introduced by Ishikawa et al.7,8 and leads to the desired trichloro-derivative,9 which can easily be converted to a tripodal amine by aminolysis with a primary amine.5... 

As noted above in Section 5.13.1 the cyano group may be easily converted into other functionalities. The a-alkylation of a nitrile (1) by treatment with an appropriate base followed by reaction with an alkyl halide enables an a-branched chain aldehyde (2) or carboxylic acid (3), or a -branched chain primary amine (4) to be readily synthesised. Furthermore an a-branched chain nitrile, or the corresponding acid or aldehyde may be further elaborated into an... 

These methods are particularly useful for branched chain primary amines. 

The ready conversion of aldehydes and ketones into oximes and their subsequent reduction is more generally applicable to the synthesis of straight and branched chain primary aliphatic amines. Reduction with sodium and alcohol is convenient and effective and two examples of its use are given in Expt 5.196. 

The intermediate imine is hydrogenated giving the secondary amine. Formation of tertiary is suppressed due to the steric hindrance of the branched chained substituent. The... 

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