5-amino-6-cyclohexyl-4-hydroxy-hexanamide derivatives as inhibitors of .beta.-amyloid protein production

A compound of Formula I and its pharmaceutically

• acceptable acid addition salts and hydrates thereof wherein
• R.sup.1 is selected from C.sub.4-8 alkyl, C.sub.4-8 alkenyl, C.sub.1-4 alkoxy-C.sub.1-4 alkanediyl, R.sup.5 -substituted C.sub.3-6 cycloalkyl, R.sup.5 -substituted C.sub.3-6 cycloalkyl-lower-alkanediyl, and Ar--(CH.sub.2).sub.n -- in which Ar is ##STR62## with R.sup.5 being hydrogen, lower (C.sub.1-6) alkyl, and lower alkoxy, and n is 1 to 4;
• R.sup.2 is independently selected from hydrogen and methyl;
• R.sup.3 is selected from lower alkyl, C.sub.3-6 cycloalkyl, C.sub.3-6 cycloalkyl-lower-alkanediyl, C.sub.3-6 alkenyl, and Ar--(CH.sub.2).sub.n --;
• and
• R.sup.4 is selected from R.sup.3, lower alkyl-thio-lower alkyl, and ##STR63## wherein R.sup.6 is lower alkyl.