GB1001941A - Spiro-(cyclohexane-1:2-coumarans) and a process for their manufacture - Google Patents

Abstract

The invention comprises compounds of the general formula I <F\1> wherein R represents an alkyl group containing 1 to 5 carbon atoms, X1 and X2 each represent a hydrogen or hydrogen atom and >Y represents a >CHOH or >C=O group. These 3-oxo-spiro-(cyclohexane - 11: 2 - coumarans) may be prepared by heating to 30 DEG to 125 DEG C. a 1-aryl-oxo - 4 - benzyloxy - cyclohexane - 1 - carboxylic acid of the general formula II <F\2> or a chloride, or bromide, or primary, secondary or tertiary amine salt thereof, or a l-aryloxy-4-hydroxy - cyclohexane - 1 - carboxylic acid of the general formula IIa <F\3> with boron trifluoride or a boron trifluoride organic complex compound, and, when an amine salt is employed as reactant, debenzylating the resultant product, and, if desired, oxidizing the hydroxyl group in the 41-position of the 41 - hydroxy - 3 - oxospiro(cyclohexane-11: 2 coumaran) so obtained from any of the above reactants to an oxo group. It is preferred to perform the ring closure reaction in the presence of a solvent or diluent, especially one of those which form complex compounds with boron trifluoride and most preferably dialkyl ethers and carboxylic acid alkyl esters. A particularly preferred boron trifluoride organic complex is boron trifluoride diethyl etherate. The debenzylation of the 3-oxospiro-41-benzyloxy-(cyclohexane - 11: 2 -coumaran) formed in the first step when employing an amine salt reactant may be effected by catalytic reduction. The oxidation of the 41-hydroxy-3-oxospiro (cyclohexane-11:2-coumarans) may be effected with the aid of compounds of hexavalent chromium, especially a suspension of a chromium trioxide-pyridine complex in pyridine. 1 - Amyloxy - 4 - hydroxy - cyclohexene - 1 - carboxylic acids of the formula IIa may be prepared by, for example, reductive debenzylation in the presence of a catalyst of the corresponding 1 - aryloxy - 4 - benzyloxy - cyclohexane - 1 - carboxylic acid of the formula II. 1 - Aryloxy - 4 - benzyloxy - cyclohexane - 1 - carboxylic acids of the formula II may be prepared by the reaction of a phenol of the formula <F\4> with 1 - trichloromethyl - 4 - benzyloxy - cyclohexan - 1 - ol in the presence of an alkali. 1 - Trichloromethyl-4-benzyloxy-cyclohexan - 1-ol may be prepared by the reaction of benzyloxy-cyclohexan-1-one with chloroform in the presence of an alkali and with the use of an appropriate diluent, preferably formaldehydedimethylacetyl, at - 30 DEG to 0 DEG C.