GB1121307A - New chromans and chromenes - Google Patents

Abstract

Novel compounds of formula <FORM:1121307/C2/1> wherein R1 and R2 are identical or different C1- 4 alkyl groups, R3 is H or an alkanoyl group of up to 5 carbon atoms, and the broken line denotes that a double bond may be present in that position, are prepared by thermal re-arrangement of a compound of formula <FORM:1121307/C2/2> to give a chromene which may be reduced, if desired, by catalytic hydrogenation to the corresponding chroman. The chromans (in which the double bond is absent) are also prepared by converting a compound of formula <FORM:1121307/C2/3> to the chroman by Claisen re-arrangement at elevated temperature and cyclization, followed by reduction of the nitro group to the amino group which may then, if desired, be acylated, or by reacting a p-hydroxyaniline in which the amino group is protected by an acyl group with a compound <FORM:1121307/C2/4> and, if desired, converting the protected amino group into a free amino group, wherein either X is a <FORM:1121307/C2/5> radical in which Z1 and Z2 are the same or different and are phenyl groups which may be ortho- or para-substituted with an electron-withdrawing substituent, e.g. nitro, halogeno, sulphonic acid or acetyl, or X is a Z3-SO2-radical where Z3 is a C1- 4 hydrocarbon group, or a phenyl or tolyl group which may be substituted with an electron withdrawing radical. 2,2 - Dimethyl - 6 - nitrochroman is prepared by treating 3-(4-nitrophenoxy)-3-methyl-but-1-ene with glacial acetic acid and concentrated nitric acid. The 4-alkynyloxy-anilines of Formula (III) above may be prepared by reduction of the corresponding nitro compounds followed, if desired, by acylation. Therapeutic compositions, which are useful for their anti-depressant, analgesic and anti-pyretic properties, and for their activity against parasitic flatworms, and which may be administered orally as powders, granules, drafts, capsules, cachets, tablets, suspensions, or emulsions, parenterally as aqueous or non-aqueous solutions or suspensions, or topically as suppositories or pessaries, contain as active ingredients compounds of Formula I above or the acid addition salts thereof.