2-Hydroxy-3-isobutyl-6-

Boron tribromide in dry chloroform was used to convert 3-isobutyl-6-isopropyl-1-methoxy-2-oxo-l, 2-dihydropyrazine to 2-hydroxy-3-isobutyl-6-isopropylpyrazine 1-oxide, and 6-isobutyl-3-isopropyl-l-methoxy-2-oxo-l, 2-dihydropyrazine behaved similarly (740a). Ohta (843) reports the preparation of 2-hydroxy-3,6-diisobutyl-pyrazine 1-oxide from 3,6-diisobutyl-l-methoxy-2-oxo-l, 2-dihydropyrazine (as intermediate) and hydrogen iodide. 

A. Salicylates - The prominence given to the hazards associated with aspirin and phenacetin lends encouragement to the search for superior compounds. Tlie n-hexylcarbonate of salicylic acid50 is claimed to have activity equal to that of aspirin but with no ulcerogenicity. 2-Hydroxy-3-isobutyl-6-methylbenzoic acid is superior5 to aspirin as an analgesic. 

Thiazole, 2-( D-galactopentaacetoxypentyl)-4-methyl-synthesis, 6, 295 Thiazole, 2-hydrazi nosynthesis, 6, 297 Thiazole, 2-hydroxy-reactions, 6, 285-286 synthesis, 6, 298, 299 tautomerism, 5, 99 6, 247, 269 Thiazole, 4-hydroxy-reactions, 5, 101 6, 287-288 synthesis, 6, 303 tautomerism, 6, 248, 269 Thiazole, 2-hydroxybenzyl-biosynthesis, 1, 96 Thiazole, 2-hydroxy-4-methyl-arylation, 6, 256 Thiazole, 2-iodo-photolysis, 6, 244 Thiazole, 2-isobutyl-occurrence, 6, 327... 

Progress has also been reported in applying titanium-mediated cydopropanation reactions as a key step in the preparation of natural products. For example, racemic stigmo-lone (8-hydroxy-2,5,8-trimethylnonan-4-one) 163, a pheromone of the myxobacterium Stigmatella aurantiaca, has been synthesized in 67% overall yield by the titanium-mediated hydroxycyclopropanation of 2-methyl-5-hexen-2-ol 161 with ethyl isovalerate 160 followed by base-induced ring-opening of the resulting 2-(3-hydroxy-3-methylbutyl)-1-isobutyl-l-cyclopropanol 162 (Scheme 11.41) [139]. 

Synonyms AI3-15288 C-07328 EINECS 204-663-5 FEMA No. 2057 Fermentation amyl alcohol Fusel oil IP3 l-Hydroxy-3-methylbutane Isoamylol Isobutyl carbinol Isopentanol Isopentyl alcohol Methyl-3-butan-l-ol 2-Methyl-4-butanol 2-Methylbutan-4-ol 3-Methylbutanol 3-Methylbutan-l-ol 3-Methyl-l-butanol NSC 1029 Primary isoamyl alcohol Primary isobutyl alcohol UN 1105. 

Refluxing a mixture of (lS, 4S, 7RS, 8R, 9R )-7-hydroxy-8-isobutyl-9-methyl-6-azatricy-clo[6.1.1.04-9]decane-6-carbaldehyde (5) and 95% formic acid for 12 hours gave a 1 1 mixture of (E)- and (Z)-(l/ , 4S,, 7S, 8/ )-9-isobutylidene-8-methyl-2-azatricyclo[5.2.1.04-8]decaiie-2-carbaldehyde (6) and the secondary formate (lR, 4S, 77 , 8R, 10S )-10-isobutyl-8-formy-loxy-7-methyl-2-azatricyclo[5.2.1.04,1°]decane-2-carbaldehyde (7) in 24% and 55% yield, respectively.87 The rearrangement is believed to involve the cyclobutyliminium ion, as shown.87... 

Some of the versions of the mixed anhydride technique discussed may involve components other than a-hydroxy acids. Therefore, the resultant products cannot be considered as main-chain modified peptidomimetics. However, on many grounds these methods are of general importance in depsipeptide synthesis. For example the classical peptide reagent isobutyl chloroformate appears to be suitable for ester bond formation through the corresponding mixed anhydride with Boc- or Z-protected amino acids and the Thr (3-hydroxy group in the synthesis of a number of natural peptide lactones.145 7 ... 

The UV spectrum of the dihydropyrrole 94a contains two strong bands [A.max log(e)] 202 (4.37), 241 (4.0). Similar spectral characteristics are displayed by 4//-4-isopropyl-2-hydroxy-5-phenyl-2,3-dihydropyrrole (94b) obtained from isobutyl phenyl ketoxime (m.p., 133-134°C, yield 26%). When stored or heated, the dihydropyrrole 94b converts into 3-isopropyl-2-phenylpyrrole (95) with elimination of water. 

The [4-hydroxy-2R-isobutyl-3-ethenylsuccinyl]-L-phenylalanine-N-methylamide (400.0 mg, 1.16 mmol) was dissolved in thiophenethyol and the mixture stirred in the dark under nitrogen at 60°C for 2 days. Ether was added to the cooled reaction mixture and the precipitated product collected by filtration. 

The solid was washed with large volumes of ether and dried under vacuum to give the [4-N-hydroxy-2R-isobutyl-3S-(thienylthiomethyl)succinyl]-L-phenylalanine-N-methylamide (320.0 mg, 0.73 mmol, 63%), melting point 184°-186°C. 

The [4-N-hydroxy-2R-isobutyl-3S-(thienylthiomethyl)succinyl]-L-phenylalanine-N-methylamide and hydroxy benztriazole were dissolved in DCM/DMF (4 1) and the mixture cooled to 0°C before adding N-(dimethylaminoethyl)-N -ethylcarbodiimide and N-methylmorpholine. The mixture was stirred at 0°C or 1 h to ensure complete formation of the activated ester. Hydroxylamine hydrochloride and NMM were dissolved in DMF then this mixture added dropwise to the cooled solution of the activated ester. After 1 h the reaction was poured into ether/water (1 1) whereupon the desired product precipitated as white crystals. These were collected by filtration, further washed with ether and water then dried under vacuum at... 

A solution of 8.2 g. (0.040 mole) of purified aluminum isopropoxide and 2.75 g. (0.011 mole) of 4-keto-l,2,3,4-tetrahydrochrysene in 25 cc. of dry toluene is refluxed for four hours, in an oil bath. After the solution has cooled slightly, 25 cc. of dry isopropyl alcohol is added to facilitate removal of acetone, the water is removed from the reflux condenser, and a water condenser set for downward distillation is attached to the top by means of a short bent tube (a Hahn partial condenser with a 1-cm. layer of isobutyl alcohol in the inner condensing tube may be used). The mixture is heated at such a rate that slow distillation occurs (2 to 5 drops per minute, the volume of solution should be maintained by further addition of solvent as needed). When the test for acetone is completely negative, f the toluene solution is cooled and the aluminum salt is decomposed with cold 10% sulfuric acid (from 5 cc. of concentrated sulfuric acid and 80 cc. of water). The product is separated with the toluene, and the solution is washed with dilute aqueous ammonia and water, and then evaporated at room temperature under a stream of air (solutions of secondary alcohols which are susceptible to dehydration should be evaporated at room temperature a stream of air should not be used with carbinols boiling below 200°). There is obtained 2.10 g. (76%) of colorless 4-hydroxy-l, 2,3,4-tetrahydrochrysene melting at 156-158°. Two recrystallizations from a mixture of benzene and petroleum ether bring the melting point to 160-162°. 

The extremely large number of lanolin derivatives has been reviewed by Barnett8 and Steel.16 Lanolin derivatives can be formed by acetylation, ethoxylation, propoxylation, alkoxylation, and isobutylation of hydroxy groups, as well as hydroxylation of the double bond in the sterol ester component. Hydrolysis of lanolin can also produce lanolin alcohols and lanolin acids, which like lanolin can be ethoxylated, acetylated, and hydoxylated. 

A widely studied example of this kind is the synthesis of methyl isobutyl ketone (MIBK, used as a solvent for inks and lacquers) from acetone. The former was previously prepared from the latter through a catalytic three-step process base-catalysed production of 4-hydroxy-4-methylpentan-2-one, acid dehydration into mesityloxide (MO), then hydrogenation of MO on a Pd catalyst. Since acetone aldolization occurs through acid catalysis as shown over a H-MFI zeolite at 433 K (MO is the main reaction product, the aldolization product being rapidly dehy-drated[5]), it is possible, by associating with the acid catalyst a hydrogenation phase,... 

Two or more compounds made up of the same number and types of atoms but with different chemical structures are known as isomers. We have already seen the difference between the two isomers -butyl and isobutyl alcohol. These are known as skeletal isomers, since they have different carbon skeletons. There are also positional isomers in which the "functional group" is located at a different position on the carbon skeleton. For example, alpha, beta, and gamma terpineol all have the same arrangement of carbon atoms but with the—OH (hydroxy) group and the double bond in different positions ... 

Dimethoxy Phenol 3,4-Dimethyl 1,2-Cyclopen tandione 5-Ethyl 3-Hydroxy 4-Methyl 2(5H)-Furanone 3-Ethyl Pyridine Furfuryl Mercaptan Geranyl Isovalerate 2,3 -Heptandione (Z)-3-Hexenyl Butyrate (Z)-3-Hexenyl Formate Hexyl Butyrate Hexyl Hexanoate Isoamyl Isobutyrate Isobutyl Formate Isobutyl Hexanoate Linalool Oxide... 

Chloro-3-isobutyl-6-isopropylpyrazine 1-oxide (109) gave l-hydroxy-3-isobutyl-6-isopropyl-2(l//)-pyrazinone (110) (KOH, H20—MeOH, reflux, 2 h 84%) 92 homologues likewise.1250... 

Hydroxymethyl-6-isobutyl-3, 6-dihydro-2,5( I //,4//)-pyra/inedione (103) gave 2-hydroxymethyl-5-isobutylpiperazine (104) (LiAlH4, THF, 0 — 65°C, 3 days 65% note survival of the extranuclear hydroxy group) also analogues likewise.229... 

Isobutyl-3-methoxypyrazine (123, R = H) gave 2-(l-hydroxy-2-methylpropyl)-3-methoxypyrazine (123, R = OH) (PiTNLi, Et20—C6H14, N2, -78 20°C,... 

Aspergillic acid (H 65, 195), 6-,vet-butyl-l-hydroxy-3-isobutyl-2( l//)-pyrazi-none, a mycotoxic Aspergillus sp metabolite [490-02-8],1024 Astechrome, 3-(l-hydroxy-3-methoxy-5-methyl-6-oxo-l,6-dihydropyrazin-2-yl-methyl)-7-(3-methylbut-2-enyl)indole Fe complex, an Aspergillus sp metabolite [75310-10-0]90... 

Hydroxyaspergillic acid (H 6), l-hydroxy-6-(l-hydroxy-l-methylpropyl)-3-isobutyl-2(l//)-pyrazinone, an Aspergillus sp metabolite.727... 

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