Tosylates, oxidation

Lafosse [342] described an oxidant-sorption method for synthesis of P(Py)/Teflon (PTFE) composites. A commercially available, surfactant-stabilized PTFE emulsion is mixed with aqueous Fe(III)-tosylate (oxidant-cum-dopant). Pyrrole is then added to this, yielding a finely divided P(Py)/PTFE composite after several h, precipitated with ethanol. SEM analysis showed the composite to be particles of 0.2 pm diameter which are presumed to be PTFE spherules coated with P(Py), rather than a homogeneous blend. Nevertheless, the composite showed conductivity of ca. 10 S/cm at a percolation threshold of ca. 16 v/v% P(Py), and acceptable microwave absorption properties. A similar emulsion method has been used by Sun and Ruckenstein [343] to synthesize P(Py)/Synthetic Rubber composites, with FeCl3 as oxidant, and several solvents (aqueous/organic combinations) and several nonionic surfactants being employed. Conductivities of the composites were ca. 3 S/cm, Tensile Strengths ca. 10 MPa, and Elongation at Breaks 38% to 166%. 

The benzylidene derivative above is used, if both hydroxyl groups on C-2 and C-3 are needed in synthesis. This r/vzns-2,3-diol can be converted to the sterically more hindered a-cpoxide by tosylation of both hydroxy groups and subsequent treatment with base (N.R. Williams, 1970 J.G. Buchanan, 1976). An oxide anion is formed and displaces the sulfonyloxy group by a rearside attack. The oxirane may then be re-opened with nucleophiles, e.g. methyl lithium, and the less hindered carbon atom will react selectively. In the following sequence starting with an a-glucoside only the 2-methyl-2-deoxyaltrose is obtained (S. Hanessian, 1977). 

Mesylated and Tosylated Celluloses. It has been estabUshed that the flame resistance of ceUulose (qv) is improved by oxidation of —CH2OH groups to —COOH (58—60). To correct some of the shortcomings of this treatment, mesyl or tosyl ceUulose was prepared and then the mesyl (CH2SO2) or tosyl (CH2CgH4S02) group was replaced with bromine or iodine (58—60) ... 

The total syntheses have yielded cobyric acid and thence cyanocobalamin. Routes to other cobalamins, eg, methylcobalamin and adenosylcobalamin, are known (76—79). One approach to such compounds involves the oxidative addition of the appropriate alkyl haUde (eg, CH I to give methylcobalamin) or tosylate (eg, 5 -A-tosyladenosine to yield adenosylcobalamine) to cobalt(I)alamine. 

By similar procedures diazirines were prepared not only from simple aliphatic ketones but also from hydroxyketones and )3-aminoketones (B-67MI50800), and so were a large number of diazirines from steroidal ketones (65JA2665). Permanganate, bromine, chlorine and hypochlorite were used as oxidants. A one-step preparation of diazirines from ketones like 3-nonanone, ammonia and chlorine has been claimed in a patent (66USP3290289). 3,3-Diazirinedicarboxylic acid derivatives like (286) were obtained directly from oxime tosylates by the action of two moles of O-ethoxyamine (81AG(E)200). 

Cholestane-3/3,5a-diol 3-acetate, 397 Cholestane-4a,5a-diol 4-tosylate, 398 Cholestane-5a,6a-diol 6-tosylate,394 5a-Cholestan-2-one, 57, 88, 427 10(5 4 H)ijAeo-Cholestan-5-one, 398 10(5 6)ij ieo-Cholestan-5-one, 392, 394 5a-Cholestan-3-one cyanohydrin, 359 5a-Cholestan-3-one cyanohydrin acetate, 360 5a-Cholestan-2a,3a-oxide, 42 5a-Cholestan-2/3,3/3-thiirane, 43 Cholest-5-ene-3, 19-diol, 268 Cholest-5-ene-3, 25-diol, 71 5(10->l/3H)flfc eo-cholest- 10(19)-ene-3/8,5a-diol 3-acetate, 397, 398 Cholest-4-ene-3,6-dione, 105 Cholest-4-en-3-one, 318 Chromium trioxide, 147, 150 5a-Conanine-3/3-ol-ll-one 3-acetate, 259 Cupric bromide, 210, 211 Cuprous chloride-catalyzed conjugate addition, 76, 80... 

Deuterio-3-iiitro-l,6-iiaphthyridiiie (168) was prepared from 4-chloro-3-iiitro-l,6-iiaphthyridiiie (166) by a reaction with tosyl hydrazide and subsequent hydrolysis of the 4-tosylhydrazino derivative (167) with Na2C03/ D2O solution (83RTC359). 7-Deuterio-l,8-naphthyridin-2(lH)-one was prepared by heating l,8-naphthyridin-2(lH)-one with deuterium oxide at 230°C for 35 h (85JHC761). Tliis deuterio compound could be converted into 2-chloro-(or 2-ethoxy-) 7-deuterio-3,6-dinitro-l,8-naphthyridine. 

Bis(3-methylsulfonyloxypropyl) amine HCI Improsulfan tosylate Bismuth oxide... 

An analogous reaction occurs with dibenzoylacetylene, whereas the reaction fails with dimethyl acetylenedicarboxylate, benzoyl chloride and tosyl chloride. Decomplexation of compound 29 to 3-(cyclohepta-2,4,6-trienyl)-3//-azepine (73%) has been achieved with trimethylamine N-oxide. 

Amino-77/-dibenz[/),t/]azepin-7-ones, e.g. 7, prepared either by successive bromination, aminodebromination, and dehydrogenation of 5-tosyl-5A/-dihydro 7>,t/]azepin-7(6//)-ones, or by the oxidation of 6-ethoxy-6,7-dihydro-5//-dibenz 7>,r/]azepincs with lead(IV) acetate followed by aminodemethoxylation, on treatment with a bidentate nucleophile (e.g.. benzene-1,2-diamine or 2-aminobenzenethiol) yield the pentacyclic systems 8 and 9, respectively.27... 

Aziridine-2-carboxylates 12 (Scheme 3.4) have also been prepared from 3-hy-droxy-a-amino esters 9 by treatment with sulfuryl chloride in place of tosyl or mesyl chloride. Treatment of 9 with thionyl chloride in the presence of triethylamine, followed by oxidation of 10 with sodium periodate and a catalytic amount of... 

Aerial oxidation of Ru(H20)g+ produces lemon-yellow Ru(H20) + (Ru-O 2.029 A in the tosylate salt)... 

Chloro-6-hydroxyiminocyclohexanone (302) (as hydrochloride) and a-amino-malononitrile (303) (as tosylate) gave 3-amino-8-chloro-5,6,7,8-tetrahydro-2-quinoxalinecarbonitrile 4-oxide (304) (Pr OH, 20°C, 18 h 46%). ... 

Acetyl-3-methylquinoxaline 4-oxide (218, X = 0) gave 2-methyl-3-(l-tosyl-hydrazonoethyl)quinoxaline 1-oxide (218, X = NNHTs) (TSNHNH2, MeOH,... 

Another reagent that convert benzylic halides to aldehydes is pyridine followed by /7-nitrosodimethylaniline and then water, called the Krohnke reaction. Primary halides and tosylates have been oxidized to aldehydes by trimethylamine N-oxide, and by pyridine N-oxide with microwave irradiation. ... 

A possible extension of the modified Neber reaction would be the synthesis of sulfonyl-substituted 2ff-azirines following the chemistry shown in Scheme 17 [27]. Unexpectedly, the oxime derived from -keto sulfones could not be converted into the oxime tosylate. Therefore, a different route to these requisite starting materials was designed, viz., via the corresponding sulfides 30 which were then oxidized with peracid to the sulfones 31. 

Regioselective Beckmann rearrangements were used as key steps in the synthesis of phosphonoalkyl azepinones (Scheme 36) [43b] and in a formal total synthesis of the protein kinase C inhibitor balanol (Scheme 37) the optically active azide 197 derived from cyclohexadiene mono-oxide was converted into ketone 198 in several steps. After preparation of the oxime tosylates 199 (2.3 1 mixture), a Lewis acid mediated regioselective Beckmann rearrangement gave the lactams 200 and 201 in 66% and 9% yield, respectively. Lactam 201 underwent a 3-e im-ination to give additional 200, which served as a key intermediate in a balanol precursor synthesis (Scheme 37) [43 cj. 

By studying the NMR spectra of the products, Jensen and co-workers were able to establish that the alkylation of (the presumed) [Co (DMG)2py] in methanol by cyclohexene oxide and by various substituted cyclohexyl bromides and tosylates occurred primarily with inversion of configuration at carbon i.e., by an 8 2 mechanism. A small amount of a second isomer, which must have been formed by another minor pathway, was observed in one case (95). Both the alkylation of [Co (DMG)2py] by asymmetric epoxides 129, 142) and the reduction of epoxides to alcohols by cobalt cyanide complexes 105, 103) show preferential formation of one isomer. In addition, the ratio of ketone to alcohol obtained in the reaction of epoxides with [Co(CN)5H] increases with pH and this has been ascribed to differing reactions with the hydride (reduction to alcohol) and Co(I) (isomerization to ketone) 103) (see also Section VII,C). 

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