GB595041A - Process for the preparation of substitution products of 2:5-dihydrofuran - Google Patents

Abstract

Dihydrofuran derivatives of the formula <FORM:0595041/IV/1> where X and Y may be hydrogen or substituent groups free from olefinic linkages and R is an aliphatic or alicyclic group, are prepared by reacting furan or a substituted furan with bromine or chlorine and an aliphatic or alicyclic mono-, or dihydric hydroxyl containing compound. A preferred form of the invention is when X is hydrogen, methyl or carboxymethyl and Y is hydrogen or methyl. Instead of chlorine or bromine, compounds which yield halogen under the conditions of the reaction may be used, such as tertiary butyl hypochlorite or bromonitro-methane. Alcoholates may be used instead of the hydroxyl containing compound. When hydroxyl compounds containing more than six carbon atoms are used, it is preferred to carry out the reaction in the presence of an organic solvent, such as tetrahydropyran, tetrahydrofuran, tetrahydrosylvan, chloroform and other saturated chlor-hydrocarbons. Compounds mentioned as being prepared by the process of the invention include 2 : 5 - dimethoxy - 2 : 5 - dihydrofuran, 2 : 5 - dimethoxy - 2 : 5 - dihydrosylvan and 2 : 5 - dimethoxy - 2 : 5 - dimethyl - 2 : 5 - dihydrofuran. These compounds were characterised by the preparation of their bis-2 : 4-dinitrophenyl hydrazine derivatives by hydrolysis of the corresponding 2 : 5-dihydrofuran compound and warming the product with a methanol solution of 2 : 4-dinitrophenylhydrazone. In examples: (1) chlorine is passed into a methanol solution of sodium carbonate and furan to saturation. Distillation of the product gives 2 : 5-dimethoxy-2 : 5-dihydrofuran; (2) as in example (1) using methyl fuorate to produce 2 : 5-dimethoxy-2 : 5-dihydromethyl furoate. A sample has been furnished under Sect. 2 (5) of 2 : 5-dimethoxy-2 : 5-dihydrofuran prepared by heating furan and methanol with chlorine and soda ash in the presence of carbon tetrachloride as solvent.