Phenyl chloroformate, conversion

Methods for the conversion of derivatives of morphine into their N-nor-com-pounds, using vinyl chloroformate,149 trichloroethyl chloroformate,150 and phenyl chloroformate,151 have been patented. Norneopine has been prepared from neopine and diethyl azodicarboxylate and by the hydrolysis of 7V-nitrosonor-neopine.152 The conversion of N-nor-bases into N-alkyl-compounds by the reduction of amides has been covered by a further patent.153... 

Japanese chemists (96) have reported the chemical conversion of kobusine into the chloramine (95). The latter was treated with sodium methoxide in methanol to afford compound 96 in which the bridged C-14-C-20 bond was cleaved. Reduction of kobusine with sodium in n-propanol, followed by acetylation afforded compound 88. Treatment of 88 with excess phenyl chloroformate in refluxing o-dichlorobenzene gave the carbamate 89. The latter was hydrogenated over Pd-C in methanol to obtain compound 90 in 94% yield. Further hydrogenation of 90 in the presence of platinum in acidic solution gave 91. Acidic hydrolysis of 91 afforded compound 92. The carbamate 92 was converted to the benzyl derivative 93 by treating with... 

A mild and general synthetic method for the facile conversion of alkyl, benzylic, aryl, and heteroaryl primary amides to the corresponding nitriles in high yields of 80-95% uses phenyl chloroformate in the presence of pyridine at room temperature [1057]. 

Prefepential conversion. Deoxyajmaline treated 18 hrs. at 20° with phenyl chloroformate in methylene chloride phenyl 21-chlorodeoxydihydrochano-ajmaline-N(b)-carboxylate. Y 96%. - The iodo analog is obtained in 94% yield in the presence of LUiodide. - Similarly N-Methylpiperidine phenyl piperi-dine-N-carboxylate. Y 92%. - Phenyl chloroformate is more effective than the alkyl esters, and compares favorably with cyanogen bromide in efficacy as well as convenience. F. e. s. J. D. Hobson and J. G. McGluskey, Soc. (G) 1967, 2015. 

Isobutyl chloroformate [543-27-1] M 136.6, b 123-127 /atm, 128.8 /atm, d 1.053, n 1.4070. It can be dried over CaCl2 and fractionated at atm press while keeping moisture out. Its purity can be checked by conversion to the phenyl urethane derivative with PhNCO [Saunders et al. J Am Chem Soc 73 3796 7957.] IR v 1780cm [Thompson and Jameson Spectrochim Acta 13 236 7959 Rose Justus Liebigs Ann Chem 205 227 1880]. 

Dimethyl[l-phenyl-4-[(tert-butyldimethylsilyl)oxy]butyl]phosphonate. (see Sch. 26 below) A solution of l-phenyl-4[(ter/-butyldimethylsilyl)-oxy]butyl dimethyl phosphite (5.94 g, 16.0 mmol) in benzene (160 mL) was divided between six quartz test tubes. The solution was degassed by bubbling argon through it for 15 min. The solution was then irradiated by a 450 W Hanovia medium pressure UY lamp. The conversion of the starting material was complete in 8h. Benzene was removed, and the yellowish liquid residue was dissolved in chloroform and applied to a silica gel column. This was eluted first with chloroform and then with 1% MeOH in CHC13. The title phosphonate was obtained as a colorless liquid (4.2 g, 72%) [133]. 

Oxidation.1 This mild oxidizing reagent can be used for selective oxidation of benzylic and allylic alcohols. Complete conversion requires 3 equiv. of oxidant. Primary and secondary alcohols are oxidized slowly in refluxing chloroform, but require a large excess of oxidant. An example is the selective oxidation of 1-phenyl-1,3-propanediol to 3-hydroxy-1-phenyl-1-propanone (52% yield). 

Preparative Methods methyl phenyl sulfoxide is treated with Hydrazoic Acid (generated by addition of sulfuric acid to a slurry of sodium azide) in chloroform maintained at 45 °C to produce -methyl- -phenylsulfoximine. The latter can be readily resolved using 10-Camphorsulfonic Acid, from the (+)-acid the salt of (+)-(5)-5 -methyl-5 -phenylsulfoximine is obtained pure by recrystallization. The Clarke-Eschweiler procedure using Formaldehyde and Formic Acid provides an effective method for conversion of the N-H sulfoximine to the title compound. ... 

Photoformylation (the photo-Riemer-Tiemann reaction) of phenols (phenol, 2-methyl, 3-methyl, 4-methyl, 4-chloro, 4-bromo, 4-nitro and 4-phenyl phenol) has also been studied by irradiation in chloroform with KOH and pyridine. The yields reported are variable but formylation is reported only to occur in the 2-position ° °. This process involves the addition to phenol of radicals produced from chloroform. An electron transfer mechanism (transfer from excited state phenol to chloroform) is thought to be involved. The radical ion pair eliminates HCl and combination affords the products 232-234 (Scheme 26). The principal product is the ether and this undergoes partial conversion to the formate. The other products formed in low yield are the aldehydes . In another application of the photo-Riemer-Tiemann reaction, this time in cyclodextrin, the phenols can be converted into 4-hydroxybenzaldehydes with high selectivity . ... 

Early assays for primidone in blood and tissue were done colorimetrically (52). The drug was extracted from the sample at pH 5 5 into a mixture of methyl acetate eind chloroform. The extract was washed with pH 11.8 buffer and evaporated. The residue was treated by a method similar to that of Dill et al (50) for diphenylhydantoin. The metabolite phenylethyl-malondiamide interferes, but can be removed after conversion with nitrous acid to a-phenyl-n-butyric acid, which is alkali-soluble (52),... 

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