Hydroxylation solvent-free preparation

Other derivatives can be prepared by reaction of the alcohol with an acid anhydride. For example, phthalic or 3-nitrophthalic anhydride (I mol) and the alcohol (Imol) are refluxed for half to one hour in a non-hydroxylic solvent, e.g. toluene or alcohol-free chloroform, and then cooled. The phthalate ester crystallises out, is precipitated by the addition of low boiling petroleum ether or is isolated by ev toration of the solvent. It is recrystallised from water, 50% aqueous ethanol, toluene or low boiling petroleum ether. Such an ester has a characteristic melting point and the alcohol can be recovered by acid or alkaline hydrolysis. 

A group of polyamides containing free hydroxyl groups were prepared by polycondensations of diethyl tartrate with various diamines under mild conditions of room temperature, without using a solvent and catalyst (Scheme 3.12) [137]. Loading of these polyamides with 2,4-D was carried out by chemical modification in the presence of dicyclohexylcarbodiimide (DCC). The effects of polymer... 

Such specificity for the primary hydroxyl indicates that preparation of desired 3 -phosphomonoesters may be difficult. For example, diphenyl phosphorochloridate will not react with 2, 5 -bis-0-methoxytetrahydropyran-4-yl uridine in a pyridine solvent, at room temperature. The free 3 -hydroxyl is too hindered to react with this bulky phosphorylating agent. However, replacement of pyridine with a more potent nucleophilic catalyst, 5-chloro-1-methylimidazole will allow product formation to occur. Other phos-phorodichloridates have been examined for the purpose of synthesis of nucleoside monophosphates. Perhaps one which has found the most use for the preparation of nucleoside T-phosphates is 2,2,2-trichloroethyl-2-chlorophenyl-phosphorochloridate. While phosphorylation will occur in pyridine, use of 1-methylimidazole provides a quicker reaction rate. This is... 

The preparation of industrially important alkyl atyl ethers was reported by Saidi and Rajabi (2003). A number of phenolic compounds such as naphthols, phenols, and hydroxyl coumarins were 0-methylated with trimethyl phosphite or trimethyl phosphate under microwave irradiation and solvent-free condition in almost quantitative yields. Reaction of 2-naphthol with trimethyl phosphate gave mixture of... 

The nitrites aie most conveniently prepared from the corresponding alcohols by treatment with nitrosyl chloride in pyridine. The crude nitrites can be precipitated by addition of water and recrystallized from appropriate solvents. However nitrites prepared from carbinols in which the adjacent carbon is substituted by halogen, free or esterified hydroxyl or a carbonyl function are very readily hydrolyzed and must be recrystallized with great care. In general the photolysis gives higher yields if purified and dried nitrites are used which do not contain acids or pyridine, although occasionally the addition of small amounts of pyridine is recommended in order to prevent hydrolysis of the nitrite. Traces of acids do in fact catalyze the thermal decomposition of secondary nitrites to equimolar amounts of alcohol and ketone. ... 

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