Cyclohexylamine oxidation

The preference for endo- or exo-cyclic elimination depends on the ring size. The cyclopentyl- and cy-cloheptyl-dimethylamine oxides (21 n = 5, 7) give more of the endocyclic alkene (22 = 5, 7) whereas the cyclohexylamine oxide (21 = 6) gives predominantly the exocyclic alkene (23 n = 6) because the six-membered ring has to adopt an unfavorable boat conformation in the transition state for endoCyclic elimination (equation 10). °... 

Crystalline solid m.p. 35-36 "C, b.p. 154--156 C, prepared by oxidizing A,A -dicycIo-hexylthiourea with HgO in carbon disulphide solution, also obtained from cyclohexylamine and phosgene at elevated temperatures. Used as a mild dehydrating agent, especially in the synthesis of p>eptides from amino-acids. Potent skin irritant. 

Cyclohexylamine is miscible with water, with which it forms an azeotrope (55.8% H2O) at 96.4°C, making it especially suitable for low pressure steam systems in which it acts as a protective film-former in addition to being a neutralizing amine. Nearly two-thirds of 1989 U.S. production of 5000 —6000 t/yr cyclohexylamine serviced this appHcation (69). Carbon dioxide corrosion is inhibited by deposition of nonwettable film on metal (70). In high pressure systems CHA is chemically more stable than morpholine [110-91-8] (71). A primary amine, CHA does not directiy generate nitrosamine upon nitrite exposure as does morpholine. CHA is used for corrosion inhibitor radiator alcohol solutions, also in paper- and metal-coating industries for moisture and oxidation protection. 

Chloro-a,/3-unsaturated aldehydes condense with ammonium thiocyanate to give isothiazoles (76EGP122249). 2,3-Diphenylcyclopropenone reacts with iV-sulfinyl-cyclohexylamine in the presence of nickel tetracarbonyl to give the isothiazolin-3-one 1-oxide (197) (79SST(5)345). Cholesteryl acetate reacts with trithiazyl trichloride in pyridine to give the isothiazolo steroid (198) (77JCS(P1)916). 

An amine-terminated poly ether (ATPE) is prepared as follows. Charge poly(tetramethylene oxide) diol (PolyTHF 1000, BASF, 75.96 g, 0.0759 m) to a 500-mL three-neck round-bottom flask fitted with a thermocouple, a mechanical stirrer, and a vacuum port. Add tert-butylacetoacetate (24.04 g, 0.1582 m) and apply vacuum. Heat at 175° C for 4 h, Fourier transform infrared (FTIR) analysis should indicate complete loss of the polyol OH absorption at 3300 cm. The room temperature viscosity of the product should be about 520 mPa-s. React this acetoacetylated product (85.5 g, 0.0649 m) with cyclohexylamine (14.5 g, 0.1465 m) at 110° C under vacuum for several hours. Cool the resultant cyclohexylaminocrotonate poly ether product to room temperature (1790 mPa-s at room temperature). 

Therefore, CL and die depolymerized product from which CL is regenerated contain various impurities which are present in widely fluctuating amounts depending on the reclamation processes involved. In particular, the presence of cyclohexanone, cyclohexanone oxime, octahydrophenazine, aniline, and other easily oxidized compounds affects die permanganate number. Also volatile substances such as aniline, cyclohexylamine, cyclohexanol, cyclohexanone, nitrocy-clohexanone, and aliphatic amines may also be present in the CL.22... 

Secondary amines synthesized by catalytic reductive alkylation of primary amines are used in a variety of fine and specialty chemical indnstries. For example, derivatives of cyclohexylamine are used as corrosion inhibitors, N-(l,3-dimethylbntyl)-N -phenyl-p-phenylenediamine (6-PPD) is nsed as an anti-oxidant in rabber indnstiy, several dialkylated diamines are used in the coatings indnstiy, while they are nsed in the pharmacentical industry as pharmacophores (1-7). Harold Greenfield and co-workers have examined the ability of platinum group metals (PGM), base metals, and their snlfides to catalyze rednctive alkylation of primary and secotrdary amines (8-11). They found that different catalysts are optimal for the... 

Preparation of 3 - Chloro-6 -cyclohexylaminoJluoran (85a). A mixture of 3, 6 -dichlorofluoran (0.1 mol), cyclohexylamine hydrochloride (0.15 mol), zinc chloride (0.3 mol), and zinc oxide (0.2 mol) was fused at 190-200 °C for 4 h. After being cooled, the solidified mixture was powdered, heated with 4% hydrochloric acid (1000 ml) to dissolve zinc chloride, and filtered. Then, the filter cake was refluxed with a mixture of toluene (400ml) and 5% aqueous sodium hydroxide (100 ml) for 1 h. The toluene layer was separated, washed with hot water, and concentrated. The residue was refluxed with methanol (200ml) for 1 h. After being cooled, the precipitate was filtered off, washed with methanol, and dried to give 3 -chloro-6 -cyclohexylaminofluoran in 60% yield as an off-white powder, mp 178-181 °C. 

Cyclohexene, conversion to cyclopen-tanecarboxaldehyde, 44, 26 purification of, 41, 74 reaction with zinc-copper couple and methylene iodide, 41, 73 Cyclohexene oxide, 44, 29 2-Cyclohexenone, 40,14 Cyclohexylamine, reaction with ethyl formate, 41,14... 

Reduction of aromatic nitro group takes preference to the reduction of the aromatic ring. Under certain conditions, however, even the benzene ring was reduced. Hydrogenation of nitrobenzene over platinum oxide or rhodium-platinum oxide in ethanol yielded aniline while in acetic acid cyclohexylamine was produced [55]. Heating of nitrobenzene with formic acid in the presence of copper at 200° gave a 100% yield of aniline, whereas similar treatment in the presence of nickel afforded 67% of cyclohexylamine [71]. 

Further routes of cyclizations have been studied in parallel in the case of cis- and rra/J5-2-hydroxymethyl-l-cyclohexylamine (106) (880PP73). The preparation of thiourea or urea adducts 107 and 108 with phenyl isothiocyanate or phenyl isocyanate proceeds smoothly. The reaction of 107 with methyl iodide and subsequent alkali treatment, by elimination of methyl mercaptan, resulted in the iminooxazine 109 in high yields. The ring closures of both cis and trans thiourea adducts to 1,3-oxazines proceed with retention. Cyclodesulfuration of the adduct 107 by mercury(II) oxide or N,N -dicyclohexylcarbodiimide resulted in the iminooxazine 109, but the yield was low and the purification of the product was cumbersome. The ring closure of 108 with thionyl chloride led to the iminooxazine 109 in only moderate yield. 

In the absence of the iV-oxide, the reaction of 3-aminopyridazino[3,4-i/ pyrimidinediones 33 with imines takes a different course (Equation 17), and cyclization of the intermediate occurs to form a pyrrole ring <2005JHC375>. The reaction with cyclohexylamine in this instance results in the formation of highly fused dimeric products <2003T7669, 2006T652>. 

Cyclamate can also be determined after its oxidation to cyclohexylamine. Cyclohexy-lamine can be quantified by HPLC with trinitrobenzenesulfonic acid precolumn derivatization and UV detection (72). Cyclohexylamine can also be converted into a fluorescent derivative, separated on a Cl8 reversed-phase column with acetonitrile Na2HP04 buffer (64 36, v/v), and quantified at 350 and 440-650 nm of excitation and emission, respectively (73). 

Formation of imidazolines 315a,b namely with cyclohexylamine and isopropylamine can be explained by the comparative ease of their oxidation and the relative stability of the corresponding ketimines. Similar heterocyclizations have been shown to proceed with other combinations of 3-alkylamino-6,8-dimethylpyrimido[4,5-c] pyridazine-5,7(6//,8//)-diones 311 and primary alkylamines. Their directionality is determined by the relative ease of oxidation of the amine reagent and the substrate amino group. Two general possibilities leading to isomeric imidazolines exist... 

An example of the simplicity and potential of the photo-oxygenation reaction is described for the preparation of (Z)-l-hydroperoxy-A-[(Z)-3-methoxycarbonyl)-2-propenylidene]cyclohexylamine A-oxide (P) starting from 2-methoxyfuran and cyclohexanone oxime, which both can be purchased and used without further purification. 

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