2.2.4.4.6.6- hexamethyl

Die Oxidation von 2,4,5-Trimethyl-anilin mit Dihydrogenperoxid/Meerrettich-Peroxidase liefert 2,2, 4,4, 5,5 -Hexamethyl-azobenzol zu 25% neben einem Benzochinon5. Eine ahn-liche Oxidation findet auch statt, wenn Aniline, die in Kontaktherbiziden Verwendung finden (z.B. Propansaure-3,4-dichlor-anilid) in die Erde gelangen. Propansaure-3,4-di-chlor-anilid wird zunachst mikrobiologisch zu 3,4-Dichlor-anilin reduziert und anschlie-Bend durch Peroxidase-Reaktion in 3,3, 4,4 -Tetrachlor-azobenzol iibergefuhrt6. 

Tellurium and dimethylstannane at 20° produced 2,2,4,4,6,6-hexamethyl-l,3,5,2,4,6-tritelluratristanninane when an excess of tellurium was used7, and 2,2,4,4,5,5-hexamethyl-1,3,2,4,5-ditelluratristanninane, when the stoichiometrically required amounts of the reagents were employed8. The heterocycles decompose in air and at elevated temperatures. 

Cyclodisilathianes may decompose thermally to silicon disulfide and silicon derivatives (R4Si) of the substituents or to trimers of R2Si=S. 1503,1532 Thermolysis of 636 with 2,2,3,3-tetramethyl-l,4-dithia-2,3-disilacyclo-hexane gives an equimolar mixture of 2,2-dimethyl-l,3-dithia-2-silacyclopentane and 2,2,4,4,5,5-hexamethyl-l,3-dithia-2,4,5-trisilacyclopentane analogous reac-... 

The reaction of oligomeric dimethyltin with (Me2SnS)3 leads to a five-membered heterocycle, 2,2,4,4,5,5-hexamethyl-l,3-dithia-2,4,5-tristannolan (12),... 

C6Hi8S3Sn3, Hexamethylcyclotristannathiane (monoclinic), 43B, 921 C6Hi8S3Sn3, Hexamethylcyclotristannathiane (tetragonal), 41B, 793 CgHi8Se2Sn3, 2,2,4,4,5,5-Hexamethyl-1,3-diselena-2,4,5-tristanno-lane, 46B, 735... 

Method I. This procedure is used for most ketone reactions. A representative example is the reductive amination of cyclopenta-none [P2P] with hexamethyleneimine [MeNHa] Hexamethyl-eneamine (I.Og, lOmmol) and cylclopentanone (0.84g, lOmmol) were mixed in 1,2-dichloroethane (35mL) and then treated with... 

Butyne trimerizes in the presence of aluminum chloride to give hexamethyl Dewar-benzene (W. Schafer, 1967). Its irradiation leads not only to aromatization but also to hexa-methylprismane (D.M. Lemal, 1966). Highly substituted prlsmanes may also be obtained from the corresponding benzene derivatives by irradiation with 254 nm light. The rather stable prismane itself was synthesized via another hydrocarbon, namely benzvalene, a labile molecule (T. J. Katz, 1971, 1972). 

The skeletal rearrangement of various strained cyclic compounds is carried out with a catalytic amount of soluble complexes of PdCl2. Namely, the rearrangements of bulvalene (67) to bicyclo[4.2.2]deca-2,4,7,9-tetraene (68)[54], cubane (69) to cuneane (70)[55], hexamethyl Dewar benzene (71) to hexa-methylbenzene (72)[56], and 3-oxaquadricyclanes[57] and quadricyclane (73) to norbornadiene[58-60] take place mostly at room temperature. Reaction of iodocubane (74) with a terminal alkyne catalyzed by Pd(0) and CuBr unexpectedly affords an alkynylcyclooctatetraene 75, without giving the desired cubylalkyne 76. Probably the rearrangement is a Pd-catalyzed reaction[61]. 

PEROXIDES AND PEROXIDE COMPOUNDS - ORGANIC PEROXIDES] (Vol 18) Hexamethyl-l,3,5-trithiane [828-26-2]... 

Compounds with active hydrogen add to the carbonyl group of acetone, often followed by the condensation of another molecule of the addend or loss of water. Hydrogen sulfide forms hexamethyl-l,3,5-trithiane probably through the transitory intermediate thioacetone which readily trimerizes. Hydrogen cyanide forms acetone cyanohydrin [75-86-5] (CH2)2C(OH)CN, which is further processed to methacrylates. Ammonia and hydrogen cyanide give (CH2)2C(NH2)CN [19355-69-2] ix.orn. 6<55i the widely used polymerization initiator, azobisisobutyronitrile [78-67-1] is made (4). 

Diperoxyketals in which the peroxide groups are in a ring are among the most thermally stable organic peroxides, eg, 3,3,6,6,9,9-hexamethyl-l,2,4,5-tetraoxacydononane(10) which has 10-h HLT = 141" C in benzene. 

The ditins as of yet are insignificant commercially, although there has been interest in hexamethyl ditin [661-69-8] (Pennwalt TD-5032) as an insecticide (164,165). 

Related to the crown ethers are compounds, such as hexamethyl-[14]-4,ll-diene (6), which differ by the replacement of one or more of the oxygen atoms by other kinds of donor atoms, particularly N or S. MacrocycHc amine and thioether compounds have been synthesized. Compounds having more than one kind of heteroatom in the ring are called mixed-donor macrocycles. The naturally occurring metaboUtes nonactin [6833-84-7] and monactin [7182-54-9] have both ether and ester groups incorporated in the macrocyclic stmcture. 

A variable pressure oil pump was used in this distillation. Approximately 10 g of a volatile component, consisting mostly of hexamethyl-disiloxane, was obtained at room temperature (15 (in) before the forerun. The forerun contained the desired product and mineral oil from the n-butyllithium solution. The pot residue was about 5 g. The submitters find the disilyl compound thus obtained is contaminated with a trace amount of mineral oil and 4-6% of a vinylsilane, probably 2-methyl-l-trimethylsiloxy-3-trimethylsilyl-2-propene. This impurity becomes quite significant if the reaction medium is less polar than the one described (e.g., too much hexane from n-butyllithium is allowed to remain behind). The spectral properties of the desired product... 

Methylarenes (see also pentamethyl- and hexamethyl- benzenes). Recrystd from EtOH and sublimed in vacuum [Schlesener et al. J Am Chem Soc 106 7472 1984],... 

Sodium bis(trimethylsilyl)amide (hexamethyl disilazane sodium salt) [1070-89-9] M 183.4, m 165-167 (sintering at 140 ). It can be sublimed at 170 /2 Torr (bath temp 220-250°) onto a cold finger, and can be recrystd from CgHg (sol lOg in lOOmL at 60°). It is slightly soluble in Et20 and is decomposed by H2O. [Chem Ber 94 1540 1961.]... 

The chain length of the polymer is then increased by reacting the wax via the hydroxyl, amino or acid end groups with a di-isocyanate such as hexamethyle-nedi-isocyanate (see Chapter 27 for the appropriate reaction). 

Solvent Et. Acetate in n-Alkane Benzyl Acetate Dm Hexamethyl- benzene Dm lO cm s l... 

Deprotonation of / /-cyclohexylfluoroacetone imines by lithium hexamethyl-disilazide or tertiary butyl lithium at very low temperature allows a regioselective alkylation at the carbon carrying fluorine [773] (equation 98). 

Simultaneous elimination of chloride ion and carbon dioxide occurs dunng heating of methyl chlorodifluoroacetate with lithium chloride in hexamethyl-phosphoric tnamide (HMPA) The difluorocarbene generated in this way is trapped by electron-rich alkenes to form 1,1-difluorocyclopropanes [26] (equation 24)... 

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