Cyclo propanols

A variety of three-membered carbocycles including cyclopropylcarbonyl and -sulfonyl derivatives, cyclopropylcarbonitriles and -methanols, nitrocyclopropanes, cyclo-propanols and cyclopropylamines have been prepared via the 1,3-elimination of HX. Some representative cyclopropyl derivatives recently prepared by this method are shown in Scheme 116-18 and in equations 8-26. Conversion of chelated homoserine, 5,to chelated 2-amino-4-bromobutyrate and treatment with aqueous base directly affords chelated 1-aminocyclopropane-l-carboxylate (equation 8)19. The 1,3-elimination in 6 interestingly leads to the preferential formation of the cis isomer, from which 7, a key structural element of synthetic pyrethroid insecticides, is obtained (equation 9)20. A sulfur substituent can serve both as an activating group and as a leaving group in this type of reaction and, thus, 1,3-bis(phenylthio)propane affords cyclopropyl phenyl sulfide upon treatment with butyl-... 

The reaction of three diastereomers of 2,3-dimethyl-l-(phenylethynyl)cyclo-propanol, i.e. (2S, 3S )-21, (IS, 2K, 3S )-22 and (IK, 2K, 3S )-23, revealed that the rearrangement proceeds with retention of configuration at the migrating carbon [13]. The reaction of the 2,3-frazzs-isomer 21 gives trazzs-4,5-di-methyl-3-phenylcyclopentenone (24) almost exclusively in good yield. When the reaction of the 2,3-czs-isomer 22 is carried out in refluxing THF for 15 min, the 4,5-czs-isomer 25 is obtained as the major product with a substantial amount of recovered 22, while prolonged reaction time results in the formation of an inse-... 

Acetoxycyclopropanol (8) can also be used as a source of cyclopropanone in thiolation reactions. Thus, 8 reacted with methanethiol in dichloromethane to yield l-(methylsulfanyl)cyclo-propanol (9). ... 

When bicyclic l-acetoxy-2,2-difluorocyclopropanes, e.g. 24,28, were reacted with lithium or sodium hydroxide in methanol the carbon-carbon bond between the bridgehead atoms was cleaved rather than the donor-acceptor-substituted bond. Two or three different products were obtained, formation of which can be rationalized by the occurrence of the cyclo-propanolate anion followed by ring opening and stabilization by protonation or elimination of fluoride. 

The Kulinkovich reaction is the titanium-catalysed synthesis of cyclo-propanols from carbo ylic esters and Grignard reagents. The reaction is very diastereoselective, and an asymmetric variant was described by Corey et al. in 1994, by using the spirotitanate 79 (Scheme 7.48). Since this work, only a few titanium-catalysed asymmetric syntheses of cyclopropanols were reported, with enantiomeric excesses never higher than 80%. ... 

Yamamoto et al. have reported a chiral helical titanium catalyst, 10, prepared from a binaphthol-derived chiral tetraol and titanium tetraisopropoxide with azeotropic removal of 2-propanol [16] (Scheme 1.22, 1.23, Table 1.9). This is one of the few catalysts which promote the Diels-Alder reaction of a-unsubstituted aldehydes such as acrolein with high enantioselectivity. Acrolein reacts not only with cyclo-pentadiene but also 1,3-cyclohexadiene and l-methoxy-l,3-cyclohexadiene to afford cycloadducts in 96, 81, and 98% ee, respectively. Another noteworthy feature of the titanium catalyst 10 is that the enantioselectivity is not greatly influenced by reaction temperature (96% ee at... 

PtRu nanoparticles can be prepared by w/o reverse micro-emulsions of water/Triton X-lOO/propanol-2/cyclo-hexane [105]. The bimetallic nanoparticles were characterized by XPS and other techniques. The XPS analysis revealed the presence of Pt and Ru metal as well as some oxide of ruthenium. Hills et al. [169] studied preparation of Pt/Ru bimetallic nanoparticles via a seeded reductive condensation of one metal precursor onto pre-supported nanoparticles of a second metal. XPS and other analytical data indicated that the preparation method provided fully alloyed bimetallic nanoparticles instead of core/shell structure. AgAu and AuCu bimetallic nanoparticles of various compositions with diameters ca. 3 nm, prepared in chloroform, exhibited characteristic XPS spectra of alloy structures [84]. 

When methanol was used to rinse a pestle and mortar which had been used to grind coarse chromium trioxide, immediate ignition occurred due to vigorous oxidation of the solvent. The same occurred with ethanol, 2-propanol, butanol and cyclo-hexanol. Water is a suitable cleaning agent for the trioxide [1]. For oxidation of sec-alcohols in DMF, the oxide must be finely divided, as lumps cause violent local reaction on addition to the solution [2]. Use of methanol to reduce the Cr(VI) oxide to a Cr(III) derivative led to an explosion and fire [3], The ignitability of the butanols decreases from n -through sec- to iert-butanol [4],... 

Interaction with a range of alcohols (n-propanol to n-octanol, benzyl alcohol, cyclo-hexanol) to form the alkoxides usually led to explosions unless air in the containing vessel was displaced by nitrogen before addition of potassium in small portions with stirring. 

Several catalytic test reactions have been used for indirect characterization of acid and base properties of solids (78). Among them, decomposition of alcohols such as 2-propanol (79,80), 2-methyl-3-butyn-2-ol (81,82), 2-methyl-2-butanol (83), cyclo-hexanol (84), phenyl ethanol (55), and t-butyl alcohol (86) have been investigated. In... 

Mizutani et al. (144) derivatized BHT to 2,6-di- er -butyl-4-methyl-4-methoxy-2,5-cyclo-hexadienone (BMMC) using up the quantitative Coppinger and Campbell reaction of BHT with bromine in methanol. Separation was carried out on a RadialPak /zPorasil column using a hexane-2-propanol mixture as mobile phase. Detection of BMMC was monitored at 236 nm,... 

X-ray crystal structures have been obtained for them and the nitrogen-nitrogen distance decreases with successive oxidation. When 1,5-diazabi-cyclo[3.3.0]octane is reacted with 3-bromo-1-propanol, followed by reaction with 40% HBF4, the hydrazinium dication (197) is obtained in 80% yield (eq 51).93b The 13C labeled hydrazinium dication (198) was prepared through double alkylation of tetramethyl hydrazine, the second alkylation being assisted by the silver (I) salt (eq 52)93c... 

Primary alcohols with an aliphatic group on the P carbon, such as 2-cyclo-hexylethanol, gave only traces or none of the cleaved products, and the starting materials were recovered. Primary alcohols in which the aromatic nucleus is located on the y carbon rather than the P carbon such as 3-phenyl-1-propanol also did not undergo significant hydrogenolysis. 

For example, a mixture of 4 mol% 2-propanol with carbon dioxide extracts up to 35 percent of nitro-triazole and a mixture of 4 mol% acetonitrile extracts up to 95 percent of cyclo-trimethylene-trinitramine. 

Propanol 2-Benzyl- XIII/1, 600 Protoadamantan 4-Oxo- E19c, 400 (aus 1,2-Amino-ol) Spiro 3.6 dec-6-en 10-Oxo- E17c, 2595 (2-Acyl — 1-ethenyl-cyclo-propan/Li —NR2 + R3Si —Cl) Spiro 4.5]dec-6-en... 

High catalytic activities, with turnovers of up to 9(X) cycles min , is displayed in the transfer hydrogenation of a,p-unsaturated ketones, such as benzylideneacetone and chalcone, using 2-propanol and catalytic amounts of [Ir(3,4,7,8-Me4-phen)COD]Cl (phen = 1,10-phenanthroline COD = 1,5-cyclo-octadiene) in a weakly alkaline medium. Other Ir-chelated complexes are also active catalysts in this reaction, with over 95% selectivity for the 1,4-reduction mode. Divalent lanthanide derivatives, such as Sml2 or Ybh in stoichiometric quantities, in THF and t-butyl alcohol or methanol reduce ethyl cinnamate and cinnamic acid to give the saturated derivatives. " Similarly, 3-methylcyclohexenone is reduced to 3-methylcyclohexen-l-ol in 67% yield, but a,p-unsaturated aldehydes are nonselectively reduced with these systems. 

Such kaleidoscopic topochemical behaviour of 2 OPr is exemplified in Scheme 6 (Hasegawa, 1992). 2 OPr crystallizes with a-type packing [2 OPr(a)] from 1-propanol solution but into the jS-type [2 OPr(j3)] from a mixture of ethanol and water. On photoirradiation using a filter (>410 nm), the a-type homo-adduct dimer (2 OPr-a-dimer) and the jS-type heteroadduct dimer (2 OPr- -dimer) are produced from 2 OPr(a) and 2 OPr(j3), respectively, both in nearly quantitative yield. The dimer crystal 2 OPr-a-dimer as-prepared is entirely stable on photoirradiation whereas, on further photoirradiation without a filter, 2 OPr-)8-dimer is converted nearly quantitatively into a highly strained [2.2] paracyclophane (2 OPr-cyclo). The photostable 2 OPr- i -dimer crystal is, however, transformed into a highly photoreactive crystal complex (2 OPr-a-dimer-PrOH) if 2 OPr-a-dimer is recrystallized from 1-propanol solution. The crystal (2 OPr-a -dimer-PrOH) photopolymerizes into a crystalline a-type homo-adduct linear polymer. Judging from their X-ray diffraction patterns, recrystallized l3-type dimer (2 OPr-)8-dimer) has a different crystal structure from that of the crystal... 

CH2)3- H3C-I Propanol Riickfl. 8 2-Amino-3-methyl-5,6-dihydro-4H-(cyclo- 80 255-257 1008... 

While dehydrating secondary alcohols over MgS04, a considerable constancy of activation energy is also observed. The alcohols cyclo-hexanol, cyclopentanol, 2-pentanol, and 2-propanol were investigated the percent of their dehydration at 370° C were as follows 17.7 17.8 18.0 18.8 and e=15.0 14.4 15.2 and 14.8 kcal/mole, respectively. This also testifies to an equal orientation of the molecules of the index group CHCO toward the catalyst (181). 

Figure 7 Colour plot of a GCxGC separation of reformulated gasoline [35]. Ol. methanol, 02. ethanol, 03. isoproyl alcohol, 04. tert-butanol, 05. n-propanol, 06. sec-butanol, 07. iso butanol, 08. tert-pentanol, 09. n-butanol, OlO. methyl tert-butyl ether. Oil. diisopropyl ether, 012. ethyl tert-butyl ether, 013. tcrt-amyl methyl ether, Nl. cyclo hexane, N2. methylcyclo hexane, IS. 1,2-dimethoxy ethane as internal standard.

The trialdehyde 38 was obtained in four steps in 60-65% overall yield from trimesic acid (34, Scheme 3). Esterification of 34 with 1-propanol in excess, by refluxing with hydrogen chloride catalyst, leads to triester 35 in quantitative yield. Hydrogenation of 35 in acetic acid solvent (Pt catalyst) yields pure cij,ds-cyclohexane-l,3,5-tricarboxylate ester 36, also in quantitative yield. Reduction of ester 36 with lithium aluminum hydri in tetrahydrofuran solvent produces c ,cis-l,3,5-tris(hydroxymethyl)cyclo-hexane cis,cis-37) in 90-95% yields. Swern oxidation of triol 37 led to cij,c -l,3,5-triformylcyclohexane 38 in 70% yield. The stereochemistry of 38, as well as that of precursors 36 and 37, was established as ca,cis in each case by high resolution H NMR. 

Cyanononane, in M-00074 2-Cyanononanoic acid, C-00028 9-Cyanononanoic acid, C-00029 2-Cyanopelargonic acid, see C-00028 w-Cyanopelargonic acid, see C-00029 l-Cyano-2-propanol, in H-00232 1-Cyanopropene, in B-00040 Cycloartanol, C-00030 Cycloartenol, C-00031 Cycloartenone, in C-00031 1,12-Cyclodocosanedione, C-00032 Cycloeucalanol, in C-00033 Cycloeucalenol, C-00033 Cyclohexaneundecanoic acid, C-00034 Cyclohexylundecanoic acid, see C-00034 9/lJ,19-Cyclolanostan-3/5-ol, see C-00030 9/5,19-Cyclo-24-lanosten-3i5-ol, see C-00031 9/3,19-Cyclolanost-24-cn-3-one, in C-00031 Cyclolaudenol, in M-00022... 

In Chapter 10, an experiment was reported in which cyclohexene was treated with OSO4 (osmium tetroxide) in anhydrous 2-methyl-2-propanol (tert-butyl alcohol) at 0°C. After standing overnight, a 45% yield of cis-l,2-cyclo-hexanediol (44) is isolated. This reaction is a dihydroxylation and the two OH units have a cis relationship. Alkenes also react with dilute aqueous potassium permanganate to give a cis diol. 

---