Amines cycloalkyl

Amines are derivatives of ammonia in which one or more of the hydrogens is replaced with an alkyl, aryl, cycloalkyl, or heterocycHc group. When more than one hydrogen has been replaced, the substituents can either be the same or different. Amines are classified as primary, secondary, or tertiary depending on the number of hydrogens which have been replaced. It is important to note that the designations primary, secondary, and tertiary refer only to the number of substituents and not to the nature of the substituents as in some classes of compounds. 

Appllca.tlons. MCA is used for the resolution of many classes of chiral dmgs. Polar compounds such as amines, amides, imides, esters, and ketones can be resolved (34). A phenyl or a cycloalkyl group near the chiral center seems to improve chiral selectivity. Nonpolar racemates have also been resolved, but charged or dissociating compounds are not retained on MCA. Mobile phases used with MCA columns include ethanol and methanol. 

At higher temperatures the mixture of 10 and methyl vinyl ketone yields the 1,4-carbocyclic compound as described previously. Methyl isopropenyl ketone (5), ethyl acetylacrylate (d), 2-cyclohexenone (21), and 1-acetyl-1-cyclohexene (22) also undergo this type of cyclization reaction with enamines at higher temperatures. This cycloalkylation reaction occurs with enamines made of strongly basic amines such as pyrrolidine, but the less reactive morpholine enamine combines with methyl vinyl ketone to give only a simple alkylated product (7). Chlorovinyl ketones yield pyrans when allowed to react with the enamines of either alicyclic ketones or aldehydes (23). 

For the regioselectivity similar rules as for the ester pyrolysis do apply. With simple, alkylsubstituted amine oxides a statistical mixture of regioisomeric olefins is obtained. On the other hand with cycloalkyl amine oxides the regioselectivity is determined by the ability to pass through a planar, five-membered transition state. This has been demonstrated for the elimination reaction of menthyl dimethylamine oxide 10 and neomenthyl dimethylamine oxide 11 ... 

The tertiary amine can be aliphatic, cycloalkyl, or heterocyclic (including pyridine). 

Macrocycles 69 were obtained in good yields by cycloalkylation of bis-aminals 67 and 68 in acetonitrile under basic conditions (Scheme 1) <1998TL6861, 2003T4573, 2005JOC7042>. The synthesis of 67 and 68 is described in Sections 12.19.5.4.3 and 12.19.5.3.4, respectively. 

Aromatic compounds, 13 108-109 13 680. See also Aromatics acylation of, 12 173-181 amination of, 12 184 arylation of, 12 170-171 Cycloalkylation of, 12 169 in diesel fuel, 12 425 formylation of, 12 178 Friedel-Crafts acylation of, 12 174 Friedel-Crafts alkylation of, 12 164 nitration of, 12 182-183 oxidative coupling of, 19 654 sulfonation of, 12 181 sulfonation reagents for, 23 521-524 Aromatic-containing polymers, sulfonation of, 23 535-536... 

In the presence of [BMIM]Br, aryl oxiranes are cleaved by a variety of amines, giving exclusively a regioselective product from benzylic attack. Other epoxides (including glycidyl aryl ethers, glycidyl alkyl ethers, and esters), alkyl oxiranes, and cycloalkyl epoxides are also converted. Remarkably, all the reactions were found to proceed efficiently at ambient temperature with high regioselectivity. The product yields reached 80-90% in a few hours. 

Thiazines such as 50 have been prepared by the reaction of C1CH2-CR1=CR2NCS (R1 = alkyl, cycloalkyl, aryl) with a secondary amine in an organic solvent (Scheme 30) (77EGP128124). 

Enamines RR CHCR CR NR4 (R-R3 = H, alkyl, aryl R4 = H, alkyl, cycloalkyl R5 = alkyl, cycloalkyl NR4R5 = heterocyclic amine) were prepared by isomerization of allylamines RR1C=CR2CHR3NR4R5 in the presence of a cationic Rh complex (RhLL1)+C104 [L = norbornadiene, L1 = R-( + )-BINAP]. 

Rearrangement alkylation of cycloalkylhydroxylamine carbonates." These hy-droxylamines, which can be prepared from cycloalkyl amines or cyclic ketones, on reaction with a trialkylaluminum rearrange to an a-alkyiated nitrogen-containing heterocycic. The complete sequence is formulated for synthesis of an a-alkylatcd piperidine (equation I). 

Katritzky and coworkers have extensively developed the activation of amines by reaction with pyry-lium salts to provide (V-alkyl (or N-aryl) pyridinium compounds. When buttressing substituents were present to discourage attack on the pyridine ring, the N-alkyl substituent was subject to displacement and elimination processes. In general, primary alkyl substituents reacted with most nucleophiles in a normal 5n2 process as shown in Scheme 12, whereas competition between substitution and elimination took place with the secondary analogs, with elimination dominating the reactions starting from cycloalkyl-amines. 

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