Carbodiimide, dicyclohexyl-, oxidation

Poly (ethylene oxide) macromonomers72 761 are made in a similar way, as the alkoxide end group is reactive enough towards benzylic halides. With methacryloyl chloride, side reactions are involved. It is better to first protonate the PEO, and then to have it react with methacryloyl chloride in the presence of some triethyl amine. One can also react co-hydroxy polyethylene oxide) with methacryloyl imidazole, or with methacrylic acid in the presence of dicyclohexyl carbodiimide (DCCf)77). 

Equimolar quantities of benzhydrol and the phosphorane (3a) were also reacted in dimethyl sulphoxide solution. Apart from bis(benzhydryl) ether (18%) and catechol monobenzhydryl ether (39%), a small amount of benzophenone (17%) was obtained. It was shown that, in the absence of phosphorane, benzhydrol is not oxidised to benzophenone by dimethyl sulphoxide. Reaction similar to that outlined in Scheme 1 is a likely possibility. Again, the alcohol is activated by reaction with the phosphorane toward nucleophilic attack, in this case by dimethyl sulphoxide. Significantly, oxidation of alcohols by dimethyl sulphoxide is usually carried out using the Pfitzner-Moffatt reagent (dicyclohexyl carbodiimide and anhydrous phosphoric acid in dimethyl sulphoxide) (13) whereas the reaction using the phosphorane (3a) is carried out under neutral conditions. Unfortunately, however, attempts to improve the yield of benzophenone have hitherto failed. 

The above obtained [(4S)-4-Methyl-5-oxo-2-(tribromomethyl)-l,3-dioxolan-4-yl]acetic acid (102.5 mg 0.250 mmol) and 2-mercaptopyridine- N-oxide (34.4 mg 0.280 mmol) were suspended in CBrCI3 (1.5ml). The reaction mixture was heated to reflux and a solution of dicyclohexyl carbodiimide (DCC) (103 mg 0.500 mmol) in CBrCI3 (1.0 ml) was added slowly over the course of 30 min. The reaction mixture was stirred for an additional hour. The product was purified by silica gel chromatography (CH2CI2/hexanes (1 2)) and was obtained as white needles from the same solvents. Yield 72 mg (65%) mp 110-113°C. 

C-(w-propyl)-N-phenylnitrone to N-phenylmaleimide, 46, 96 semicarbazide hydrochloride to ami-noacetone hydrochloride, 45,1 tetraphenylcyclopentadienone to diphenyl acetylene, 46, 44 Alcohols, synthesis of equatorial, 47, 19 Aldehydes, aromatic, synthesis of, 47,1 /8-chloro-og3-unsaturated, from ketones and dimethylformamide-phosphorus oxychloride, 46, 20 from alkyl halides, 47, 97 from oxidation of alcohols with dimethyl sulfoxide, dicyclohexyl carbodiimide, and pyridinium trifluoroacetate, 47, 27 Alkylation, of 2-carbomethoxycyclo-pentanone with benzyl chloride, 45, 7... 

The reaction between hydroxypropyl phosphate and dicyclohexyl carbodiimide in aqueous pyridine leads to 2-hydroxy-l,3,2 dioxaphosphinane 2 oxide, which if isolated and reacted further under anhydrous conditions, gives 2,2 oxybis-(l,3,2 dioxaphosphinane 2,2 oxide) (6.940) which is a diphosphate. 

Four additional polypeptides have been identified in the membrane sector. One of these, a strongly hydrophobic protein, seems to contain the binding site of dicyclohexyl-carbodiimide, an inhibitor of oxidative phosphorylation, and probably also of oligomycin. These four polypeptides are coded for by the mitochondrial genome, the others by the nuclear genome. 

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