R-Butanol

Melbylpropene, isobutylene, isobutene, Me2C CH2 Prepared by heating r-butanol with oxalic acid. 

A third approach to 3-amino-/3-lactams is by Curtius rearrangement of the corresponding acyl azides. These are readily prepared from r-butyl carbazides, available via photochemical ring contraction of 3-diazopyrrolidine-2,4-diones in the presence of f-butyl carbazate (c/. Section 5.09.3.3.2). Thus treatment of (201) with trifluoroacetic acid followed by diazotiz-ation gives the acyl azide (202) which, in thermolysis in benzene and subsequent interception of the resulting isocyanate with r-butanol, yields the protected 3-amino-/3-lactam (203) (73JCS(P1)2907). 

The reactions of the cis and irons isomers of 4-/-butylcyclohexyltrimethylammonium chloride with potassium t-butoxide in r-butanol have been compared. The cis isomer gives 90% 4-r-butylcyclohexane and 10% AyV-dimethyl-4-r-butylcyclohexylamine, while the irons isomer gives only the latter product in quantitative yield. Explain the different behavior of the two isomers. 

The stereochemistry of hydrogen-deuterium exchange at the chiral carbon in 2-phenylbutane shows a similar trend. When potassium t-butoxide is used as the base, the exchange occurs with retention of configuration in r-butanol, but racemization occurs in DMSO. The retention of configuration is visualized as occurring through an ion pair in which a solvent molecule coordinated to the metal ion acts as the proton donor... 

Functionality H2Cr04 acetone CrOs, aq. acetic acid CrOs pyridine NBA r-butanol DMSO DCC Oppenauer DDQ MnOa Pb(0Ac)4 pyridine... 

There are very few homolytic reactions on triazolopyridines. A suggestion that the ring opening reactions of compound 1 involved free radical intermediates is not substantiated (98T9785). The involvement of radical intermediates in additions to ylides is discussed in Section IV.I. The reaction of radicals with compound 5 and its 1-substituted derivatives gives 4-substituted compounds such as 234 (96ZOK1085). A more detailed study of the reaction of the 1-methyl and 1-phenyl derivatives with r-butanol and ammonium persulfate produced 4-methyl substitution with a silver nitrate catalyst, and the side chain alcohol 235 without the catalyst (96ZOK1412). 

An excellent route to cyclohexylamines is by hydrogenation of the corresponding aniline over rhodium or ruthenium (17,18,19 2 36,63,64). Rhodium has proved especially useful in saturation of alkoxyanilines with minimal hydrogenolysis of the alkoxy function (45), The extent of hydrogenol ysis occurring in saturation of alkoxyanilines depends also on the solvent. Hydrogenolysis of p-methoxyaniline over Ru(OH)2 fell with alcohol solvent in the order methanol (35%) > ethanol (30%) > propanol (26%) > butanol (22%) > isopropanol (16%) > r-butanol (8%) (43). 

Chlorbutol (trichlorobutanol trichloro-r-butanol trichlorobutanol). Typical in-use concentration 0.5%. It has been used as a preservative in injections and eyedrops. It is... 

Figure 2 Effect of spinning rate on the interfacial tension of r -butanol/water system at 30°C.

The water is present in such large excess relative to the isobutylene and r-butanol con-... 

Ring contraction by (Si - C) vinyl migration took place when the diazo-silacyclohexadiene 393 was heated in the presence of anhydrous CuS04 388>. The silafulvene 394 was not isolated, but it could be trapped by r-butanol, benzophenone or benzaldehyde to give 395,396a and 396b, respectively. Silane 395 was also obtained... 

JOC3570). Diazotization of l-methylimidazole-5-carbohydrazide (103) followed by treatment with r-butanol gave the carbamate (104), which was dissolved in cold tetrafluoroboric acid when evolution of gas had ceased, the solution was treated with sodium nitrite and irradiated. However, unlike the 4-aminoimidazoles (Section III,A,2), this reaction produced none of the desired 5-fluoro-l-methylimidazole (105) (Scheme 10). Although 5-amino-1-methylimidazole (96 R = Me, R2 = H) was almost certainly formed, ultraviolet spectral analysis showed only traces of a diazo-nium chromophore after addition of nitrite, indicating compound (96 R1 = Me, R2 = H) to be extremely unstable under the acidic reaction conditions (78JOC3570). 

Triazoles (386, R1 = COOMe) were treated with potassium tert-butylate in a mixture of f r/-butanol and benzene for 15-60 min to give (substituted amino)methoxycarbonylmethylenemalonates (387, R1 = COOMe) in 28-54% yields. In the case of the acetyl derivative (386, R = Ph, R1 = COMe), the reaction was carried out in chloroform in the presence of triethylamine at ambient temperature for 8 hr, to give (pheny-lamino)acetylmethylenemalonate (387, R = Ph, R = COMe) in 38% yield. (Phenylamino)acylmethylenemalonates (387, R = Ph,R = COMe, COPh) were also prepared in 62-74% yields when diazo derivatives (388, R1 = COMe, COPh) were heated in benzene for 4-24 hr (80T1821) (Scheme 34). 

The kinetics of the alkaline hydrolysis of 2-methylpentyl salicylate (24) have been studied in various aqueous propanol and r-butanol mixtures and in mixtures of water and ethane-l,2-diol. ° Further smdies of the aminolysis of ionized phenyl salicylate (25) have been reported, in which it was observed that, in mixed acetonitrile-water solvents, glycine, 1,2-diaminoethane and 3-aminopropanol all reacted as did simple amines, via an intramolecular general-base-catalysed process. ... 

Prslparativ wegen der hohen optischen Ausbeuten besonders interessant ist die von Brown und Zweifel (51, 53, 54, 325) entdeckte asymmetrische Hydroborierung 1,2-di- oder trisubstituierter Athylen-Doppelbindungen. Man setzt hierbei das aus (+)-a-Pinen, NaBH und BFg leicht zugang-liche (—)-Diisopinocamphenylboran VII mit cis-Olefinen um und oxy-diert die entstehenden Borane unter Retention der Konfiguration zu sec. Alkoholen. Auf diese Weise erhalt man z.B. aus cis-Buten-(2) mit p = 87% (R)(-)-Butanol- 2). 

Problem 13.39 Write a structural formula for a Grignard reagent and a carbonyl compound which react to give each of the following alcohols after hydrolysis (a) 2-butanol, (f>) benzyl alcohol, (c) 2,4-dimethyl-3-pentanol, (d) r-butanol. M... 

Tb a solution of 7 (458 mg, 1.7 mmol) and /V-methyl morpholine /7-oxide (244 mg) in r-butanol (1 mL), a few crystals of osmium tetraoxide dissolved in THF (1.5 mL) were added. After 3 days 40% aqueous solution of NaHS03 (3 mL) was added, the mixture was stirred for additional 30 min, and extracted with ethyl acetate (3 x 20 mL). The extracts were dried (MgS()4) and concentrated to dryness. The residue was purified by chromatography on a silica gel column with light petroleum-ether-methanol (4 5 0.5) to yield 9 (371 mg, 72%) mp 89.5° (from a mixture of hexane and ethyl acetate), [a]D + 52° (c 1.0, CHClj). 

Methyl-17a-hydroxy-20-ketopregnanes via 17-Hydroperoxides86 Sodium hydride (7.5 g) is dissolved in a mixture of r-butanol (100 ml) and dimethyl-formamide (150 ml) at ambient temperature, approximately 1 hr being taken... 

Fig. 79. I3C NMR spectra showing that when 2-methylpropene (isobutene) is intercalated in a synthetic hectorite r-butanol is formed when the guest species reacts with the interlamellar water. The peaks labeled 1 and 2 refer to the two distinct types of carbon atom in r-butanol (453).

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