Leukotriene antagonists and use thereas

DETAILED DESCRIPTION AND PREFERRED EMBODIMENT The present invention relates to new organic compounds that are useful in the treatment of immediate hypersensitivity reactions.
A preferred group of compounds are the compounds of Formula I wherein: (a) R.
sub.
1 is C.
sub.
1 -C.
sub.
6 alkyl, especially methyl, (b) R.
sub.
2 is C.
sub.
1 -C.
sub.
6 alkyl, especially propyl, (c) R.
sub.
3 is hydrogen, (d) R.
sub.
5 is hydrogen, (e) R.
sub.
6 is hydrogen, (f) Z is ##STR3## --NH--, or especially --O--, (g) A is --O--, --CO--, or --CHOH--, and (h) R.
sub.
4 is --COOH or 5-tetrazolyl.
An especially preferred group of compounds are those of Formula Ia: ##STR4## and pharmaceutically acceptable salts thereof wherein: R.
sub.
2 ' is C.
sub.
1 -C.
sub.
6 alkyl, especially propyl; and A' is --O--, --CO--, or --CHOH--.
The following definitions refer to the various terms used throughout this disclosure.
The term "C.
sub.
1 -C.
sub.
10 alkyl" refers to the straight and branched aliphatic radicals of 1 to 10 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, amyl, isoamyl, sec-amyl, sec-isoamyl (1,2-dimethylpropyl), tert-amyl (1,1-dimethylpropyl), hexyl, isohexyl (4-methylpentyl), sec-hexyl (1-methylpentyl), 2-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 1,2,2-trimethylpropyl, 1,1,2-trimethylpropyl, heptyl, isoheptyl (5-methylhexyl), sec-heptyl (1-methylhexyl), 2,2-dimethylpentyl, 3,3-dimethylpentyl, 4,4-dimethylpentyl, 1,2-dimethylpentyl, 1,3-dimethylpentyl, 1,4-dimethylpentyl, 1,2,3-trimethylbutyl, 1,1,2-trimethylbutyl, 1,1,3-trimethylbutyl, octyl, isooctyl (6-methylheptyl), sec-octyl (1-methylheptyl), tert-octyl (1,1,3,3-tetramethylbutyl), nonyl, 1-, 2-, 3-, 4-, 5-, 6-, or 7-methyloctyl, 1-, 2-, 3-, 4-, or 5-ethylheptyl, 1-, 2-, or 3-propylhexyl, decyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, or 8-methylnonyl, 1-, 2-, 3-, 4-, 5-, or 6-ethyloctyl, 1-, 2-, 3-, or 4-propylheptyl, and the like.
The term "C.
sub.
1 -C.
sub.
10 alkyl" includes within its definition the terms "C