Cyclopentylamines

Cyclopentene oxide 5-0xabicyclo[3.1.0]hexane (8,9) (285-57-6) cis-2-(2-Propeny1)cyclopentylamine Cyclopentanamine, 2-(2-propenyl)-,... 

All stated pK values in this book are for data in dilute aqueous solutions unless otherwise stated, although the dielectric constants, ionic strengths of the solutions and the method of measurement, e.g. potentiometric, spectrophotometric etc, are not given. Estimated values are also for dilute aqueous solutions whether or not the material is soluble enough in water. Generally the more dilute the solution the closer is the pK to the real thermodynamic value. The pK in mixed aqueous solvents can vary considerably with the relative concentrations and with the nature of the solvents. For example the pK values for V-benzylpenicillin are 2.76 and 4.84 in H2O and H20/EtOH (20 80) respectively the pK values for (-)-ephedrine are 9.58 and 8.84 in H2O and H20/Me0CH2CH20H (20 80) respectively and for cyclopentylamine the pK values are 10.65 and 4.05 in H2O and H20/EtOH (50 50) respectively. pK values in acetic acid or aqueous acetic acid are generally lower than in H2O. 

The approach used for the initial synthesis of PC s via cyclopentylamine intermediates was shortened and broadened to include the synthesis of 11- i-PG s and also chiral PG s by resolution. 

These Br nsted-type plots often seem to be scatter diagrams until the points are collated into groups related by specific structural features. Thus, p-nitrophenyl acetate gives four separate, but parallel, lines for reactions with pyridines, anilines, imidazoles, and oxygen nucleophiles.Figure 7-4 shows such a plot for the reaction of trans-cmmm c anhydride with primary and secondary aliphatic amines to give substituted cinnamamides.All of the primary amines without substituents on the a carbon (R-CHi-NHi) fall on a line of slope 0.62 cyclopentylamine also lies on this line. If this line is characteristic of normal behavior, most of the deviations become qualitatively explicable. The line drawn through the secondary amines (slope 1.98) connects amines with the structure R-CHi-NH-CHi-R. The different steric requirements in the acylation reaction and in the model process... 

Likewise, l-[4-methylbenzyl]-4,7-dihydroxy-l,2,3-triazolo[4,5-d]pyridazine 275 reacts with phenylhydrazine, HMDS 2, and (NH4)2S04 to give the monoamino product 276 in 60% yield [83]. Reaction of l-benzyl-3-n.-butyl-4-hydroxy-l,2,3-triazo-lo[4,5-d]-pyrimidine 277 for 8 h at 120°C with cyclopentylamine, HMDS 2, and (NH4)2S04 affords the aminated product 278 in 49% yield [84] (Scheme 4.33). 

CYCLOOCTENE, 1-NITRO-, 50, 84 CYCLOPENTANECARBOXALDEHYDE, 1-PHENYL-, 51, 24 Cyclopentane-1,3-dione, 52, 4 Cyclopentanones, 54, 32 CYCLOPENTYLAMINE, 1-PHENYL-,... 

Problem 18.60 Synthesize the following compounds from alcohols of four or fewer C s, cyclohexanol and any needed solvents and inorganic reagents, (a) n-hexylamine, (h) triethylamine N-oxide, (c) 4-(N-methylamino)heptane, (d) cyclohexyldimethylamine, (e) cyclopentylamine, (/) 6-aminohexanoic acid. 

Grey and Vega (161) have demonstrated the use of the TRAPDOOR experiment for measuring the 27Al quadrupole coupling constant in zeolites and applied it to studies of trimethylamine in zeolites. In other spectroscopic work, Fripiat and co-workers (162) used REDOR and various other NMR methods to characterize acid sites in zeolites treated with ammonia. Ernst and Pfeiffer (163) have reported a 13C MAS NMR study of the reactions of methanol and ammonia to make methylamines in zeolite HZSM-5. We reported NMR evidence of the synthesis of cyclopentylamine from cyclo-pentanol and ammonia on zeolite CsX (102). 

In the course of the catalytic hydrogenation of a,us dinitriles over Raney nickel, by-products are obtained from C-N and C-C bond formation. The mechanism of the formation of these compounds was investigated. Cyclic and linear secondary amines can result from the same secondary imine through a transimination process involving a ring-chain tautomerism. Stereochemical results for 2-aminomethyl-cyclopentylamine (AMCPA) are in accordance with a specific cyclisation pathway favored by an intramolecular hydrogen bond giving rise to the cis isomer from aminocapro-nitrile, unfavored in the case of adiponitrile which leads to the trans AMCPA as the major isomer. 

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